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The image above by Dr. Kenneth Carpenter is a scientific view of what the Marsh Felch Dinosaur Quarry looked like about 152 million years ago. It is shown in comparison to what it looks like today.      

The quarry site today represents layers of inter-bedded sandstones, thin limestones, and shales that record the history of river channels, ponds, and floodplains over a period of time. For reasons not entirely understood, a prolifically large number of dinosaurs and other animals died there and were then buried and fossilized. They were then carefully excavated by Marshall Felch in the 1880’s.    

A primary reference for this general description is the 1998 publication by Kenneth Carpenter and Emmet Evanoff’s where the stream channel systems in the immediate vicinity of the channels that Marshall excavated and removed are described in detail. Secondly, they utilized detailed descriptions of the river channels and rock layers in Marshall’s letters (Evanoff and Carpenter 1998).

A second general resource about life in the late Jurassic period is found in the book Jurassic West, the Dinosaurs of the Morrison Formation and Their World by John Foster (Foster 2007). These two resources provide the primary references used here for a simple summary of the ancient ecosystem Marshall was uncovering with some emphasis on the Stegosaurus.

Marshall lived and breathed every aspect of the quarry for over five years and over time grew more and more curious about what the place was like where the dinosaurs lived.  He most certainly would have appreciated seeing Carpenter’s depiction of the quarry long ago and hearing a description of the plants and animals that lived there. 

Meandering Rivers

The simplified drawing above is used in various educational sites. It depicts the core concepts of a meandering river.  The river pushes outward on the bend leaving behind sandy material along the inside of the curve (lateral accretion deposits). Occasionally the banks fail and the river spills out onto the surrounding floodplain leaving behind a deposition feature called a crevasse splay.  How the river moved and shifted over time has much to do with what Marshall discovered and excavated. 

Relatively rapid changes in a river course take place in a natural system which seems to be the case when reading Marshall’s descriptions of what he was excavating. Although we don’t know for certain,  it seems that the dinosaurs he was excavating didn’t die all at once, but rather over a few days, weeks, or even months. Paleontologists today don’t just look at the dinosaur being excavated but clues all around in the surrounding rock layers that can provide insights in the place the dinosaur died. The goal is to obtain a clearer picture of the ecosystem the dinosaurs lived in. 

An excavation today would be much slower and more thorough but Marshall was being pressed hard to excavate as thoroughly and yet quickly as possible. The 1870’s and 80’s were the beginning years of major dinosaur discoveries in the American West and Professor Marsh’s emphasis was to present new genus and species of animals (especially dinosaurs) to the world.  Marshall was seldom asked by Marsh about the old river channel but his notes, drawings, and maps demonstrate he had a good deal of understanding of it. On June 23, 1886 Marshall wrote; “The animal here lay on its left side and up against the bank of our old river bed-bringing left hip the highest the right hip and some leg bones having slid downhill toward the bottom of the bed.”

If the excavation were done today more emphasis would be placed on the details of this river system. Fortunately we now have a rich spectrum of knowledge regarding the world in the late Jurassic period, not just here in Western North America, but around the world.  Perhaps some additional work could be done along the edges of the old workings in the future to expose the old river channel that Marshall was working in. It might be enlightening to gain a clearer picture of the events leading to such a mass assemblage of animals buried in a relatively small area.   

The Marsh Felch Dinosaur Quarry 152 million years ago

Deposition of sand, silt, clay, and other materials were deposited in and around streams, rivers, ponds, and lakes over a seven million year period recording that story.  The layers of rock where both Marshall Felch and the Lucas Brothers were working are known today across the American West as the Morrison Formation.  Here in the Garden Park National Natural Landmark, the formation is about 350 feet thick. The latter part of the Jurassic period was obviously a much different place in western North America than today. Maybe it was even stranger than what our initial assumptions are.

The streams and rivers began their journeys a few hundred miles to the west in an Andean type volcanic mountain range. They meandered from west to east across a vast relatively flat green landscape in western North America as it was then, between 155 and 148 million years ago. A few hundred years ago, if we were flying over the Great Plains it would have been a remarkable grassland ecosystem with ribbons of forested areas along the rivers and a host of animals including vast herds of bison. From up high in an airplane the Morrison ecosystem would have looked eerily similar but up close these Jurassic meadows, rivers, ponds, and lakes would have supported an ecosystem far different than we can easily imagine. 

The climate was semi-arid with wet and dry seasons. Overall it was quite warm and rarely did it ever freeze. Surprisingly there was not enough rainfall to grow the mass of vegetation needed to support a whole host of very large and hungry dinosaurs but yet, the vegetation was there. Scientists today have determined that the water the plants needed was the result of high ground water tables that existed, particular in this part of the continent at the time.

Between the different rivers there were vast meadows that were covered with ground ferns and short herbaceous cycad like plants. These fern meadows supported grazers like Stegosaurs, herds of slender long-necked and very long tailed Diplodocus, various sizes of bipedal dinosaurs moving around in groups, little long-legged running dry-land crocodiles, and occasionally big theropods, like an uninvited Allosaurus, crashed the party. 

The riparian areas along the streams and rivers were forested with a rich variety of tree ferns. Conifer trees similar to modern redwoods, Norfolk pines, and giant kauri tree of New Zealand, and Ginkgo trees similar to those with us today were plentiful. Below the tree cover was an under-story of various ground ferns and low growing palm-like cycad plants somewhat like we might see in the meadows but different species. Along the edge of the river were horsetails and in the river were a few smaller fish darting about while larger lung fish hid here and there. Within this riverside environment were; turtles, crocodiles, lizards, frogs, burrowing and tree climbing mammals all no bigger than a squirrel, and a whole host of buzzing and biting insects. Bipedal plant eating dinosaurs of various sizes were common, while a variety of larger long necked and long tailed dinosaurs such as Brontosaurus (Apatosaurus), Diplodocus, Haplocanthosaurus, and Brachiosaurus each had their own favorite niche (dinner plans).  Complimenting this crew was the odd-looking colorful Stegosaurs with plates on their back.  For some small, injured, or careless animals, the last thing they saw was a Ceratosaurus with very large teeth heading their way.  

Such a large concentration of dinosaur skeletons at Marshall’s dinosaur quarry wasn’t terribly complicated. It was simply the result of the normal movement of meandering rivers but here it seems a combination of severe, and possibly a prolonged drought was underway. Maybe there was just enough water remaining in a low spot in the old channel to attract thirsty dinosaurs and other animals. One of these animals could have included a Stegosaurus driven to exhaustion from the heat and the lack of food and water. The Stegosaurus took its last breath, laid down on its left side on the river bar and died. Our drought mortality victim was not alone, nearby was an Allosaurus and a Ceratosaurus. Normally these predators would have scavenged the Stegosaurus carcass but they too must have simply died from lack of food and water in the same general time frame. Limited rainfall over a few days, weeks, or months brought in just enough sediment so that our Stegosaurus was gently covered over preventing any major scavenging. Maybe think of it like pulling a blanket over a loved one who has passed away.

The drought must have been severe because Marshall found skeletons both above and all around the Stegosaurus. The difference was that most of these animals were exposed just long enough that their bodies were at least partially scavenged. Skeletons being pulled apart and somewhat scattered is not an unusual thing for mass mortality river type sites like this. 

Once initially buried, deposition from rivers, lakes, and ponds continued to pile up onto our Stegosaurus for another four million years. Geologic conditions then changed and no deposition of any kind took place in this part of the world, therefore there is a thirty million gap in the geologic record for this part of the world. Around 110 million years ago deep seated tectonic forces began to cause subsidence of the land and before long the place where Stegosaurus and the other the dinosaurs had lived dropped well below sea level. A whole new underwater story then took place. Above the deeply buried dinosaurs was a great sea with giant swimming reptiles, ammonites, and clams. A completely different type of rock record stretching over thirty million years was the result. Like the dinosaur story this story would also come to an end.

Beginning about 65 million years ago the first of several mountain building episodes that created the Rocky Mountains was underway. These uplifts continued intermittently with the most recent uplifts taking place in the last few million years. The geologic story over the last 65 million years is its own fascinating and complex geologic story.  One benefit for paleontologists is that these mountain uplifts lifted up long buried sedimentary rock layers thousands of feet back well above sea level. Some of these layers included the Morrison Formation and although it still remains at great depth some places it was lifted up so high than in others much of it eroded away.  In our special place we call the Garden Park-National Natural Landmark and more specifically the Marsh Felch Dinosaur Quarry were not only raised up just the right amount. Even then though Mother Nature took its toll as large slump (landslide) blocks are common in the Garden Park National Natural Landmark. 

In 1877, a curious little ten-year-old girl named Sadie noticed bones buried in the rock near the edge of a cliff. These turned out to be the bones of a very strange animal with a very long neck and even longer tail that lived 152,000,000 years earlier. That same year Professor Mudge, Sam Williston, and Marshall excavated a Diplodocus. Marshall was an experienced excavator and now Marshall was getting ready to do some of his finest work beginning in 1883. In 1885 he will come across a Stegosaurus.   

“Such Success is Most Remarkable”

Almost 30 years after Marshall excavated the Stegosaurus, Charles Gilmore described the acquisition by the National Museum of Natural History (NMNH) of this material.

The description included the drawing to the left (Gilmore, 1914).

“When the Marsh collection was received at the National Museum in 1898 and 1899 a very small part of the Stegosaurian material was in condition for study. The preparation of this material was begun m 1906 and has continued, barring some interruptions, up to the close of the year 1913…The material at hand includes the remains of several individuals, each of which represents a considerable part of the skeleton; also a vast number of separate bones. Of the associated skeletons the type of Stegosaurus stenops Marsh is worthy of especial mention, since it represents the most perfect specimen of the genus yet discovered and the only one known that gives positive evidence as to the arrangement of the dermal armor…The extensive collection of Stegosaurian remains in the National Museum has, with few exceptions, been obtained from two important, though widely separated, fossil deposits. These are Quarry 13, located in Albany County, Wyoming, and Quarry No. 1, in Fremont County, Colorado. The former, I may say without fear of contradiction, was the source of the greatest accumulation of Stegosaurian remains ever discovered, and from the latter has been obtained the wonderfully complete skeleton of Stegosaurus stenops (No. 4934, United States National Museum), in addition to many other valuable specimens.” (Gilmore 1914)


“The fossil bones lay buried in a thick stratum of heavily bedded sandstone. Not only was the stone extremely hard, but it was also considerably fractured, both vertically and horizontally, in such manner as to greatly increase the difficulties encountered in properly taking up the bones.

Mr. Felch, however, overcame these difficulties in a most commendable manner. The specimens were quarried out in large blocks of stone, the contained fossils thus being retained in their original relative positions. Each articulated or partially articulated skeleton was given a number (for example, the type of Stegosaurus stenops was designated by the field number “Sk. 11 “). The skeleton was divided into irregular-sized groups, each group being indicated by a number, as Gr. 1, Gr. 2, etc. The pieces of stone comprising the different groups were lettered, each group beginning with A and continuing alphabetically. (Gilmore, 1914)

The picture below shows the Stegosaurus during the preparation phase This picture appears to be the bottom side of the Stegosaurus. Both sides were prepared and the initial exhibit include mirrors to enable visitors to see key parts of the underside of the Stegosaurus. Picture courtesy of the National Museum of Natural History. 

The skeleton, group, and block designations were painted on the stone, so that, aided by the rough sketch diagrams made and properly marked at the same time, the work of assembling the blocks in the laboratory was reduced to a minimum. Considering the early date of this work, which was before the development of modern field methods, the painstaking care and ingenuity displayed by Mr. Felch in collecting this difficult material with such success is most remarkable.”  (Gilmore, 1914)

The image above of Stegosaurus as it looked near the end of its preparation phase around 1912. Images of Stegosaurus in preparation are courtesy of the National Museum of Natural History in Washington D.C. This particular specimen became lovingly known at the National Museum of Natural History as the “Roadkill”.  The term has since been used for dinosaur skeletons so perfect (and so rare) that they have the appearance of being hit by a bus and falling over. 

Ranching and Farming From March through July?

About the time Marshall was finishing up shipping Stegosaurus bones from work in 1885 to Professor Marsh, he was having serious reservations about continuing to excavate dinosaurs in the spring and early summer. This was the time period when the ranch needed the most attention. When Marshall was geared up to start excavating at the beginning of 1885 Marsh had unexpectedly pulled the rug out from under him stating he suddenly had no funding until July. This caused Marshall and certainly Amanda great consternation on a number of fronts. On the other hand Marshall noticed was that he had time to get the ranch and farm in order when it needed the most attention and over the last few months he thought about this a lot. Perhaps he would have thought about this a lot less if Professor Marsh put in some effort publicly recognizing Marshall’s work or paid him enough to make this all worthwhile but neither of these avenues were going to happen.  

Marshall suggested to Professor Marsh that for 1866 he could dig dinosaurs before April and after July.  He described the dilemma to Marsh on January 24, 1886; 

when help here is always scarce – crops need the most careful and constant attention… I have to drop my farm work, to go to work in the quarry – start out to get help for that work – also to work on the ranch.  I find all good hands, or men that are of much account either went to the mines in the spring or hired out March 1” for the full seasons work, and so am compelled to depend on some floating, transient help – for which in order to get at all I must pay the very highest price, as the labor market is in their hands Suppose, even I am fortunate enough to get a first class hand to work my ranch, he is a stranger to the peculiar lay of the ground (an item of no small importance in farming by irrigation) and work as hard and faithful as he may will be unable to accomplish little more than half that I would with far less hard labor, besides more or less of my time must to some extent be given daily in planning and directing him and where the work may be applied to the best advantage that any good results may be had.

Marshall may have been encouraged by Amanda to stand up and to quit letting Professor Marsh take advantage of his good nature.  Marshall not only stated the case, he laid out the terms of what he needed; 

“After my experience of last year in doing business this way I cannot take the same chances again… What I wish to do with my ranch is, either to let it to some good man – or hire a good man to carry it on from the first of March when I can stand a better chance of getting good men – and in either case, I must, if I go to work in the quarry at all, begin by the first of April in order to meet expenses and not get behind.” 

Marshall pointed out that the previous year he had been in a bind because of Weld’s preemption land claim and to protect the quarry (that was in the interest of Professor Marsh) he not only didn’t receive adequate pay he ended up in his debt.  He stated that he had been protecting the claim from other collectors and Marsh had done little to recognize this effort.  He made it known that he needed to know by the 1st of March what the Professor was willing to do so he could plan accordingly.  

Professor Marsh knew clearly that this quarry was providing some outstanding results. He could also tell that Marshall had evolved into a great collector.  He had a lot going on at the Peabody and other collecting localities so he pleaded poverty on the 12th of February but agreed to give Marshall $10 more per month, additional money to pay for a man to work at the ranch for three months, and $50 for some of the improvements Marshall had paid out of his own pocket. This arrangement seemed fair to Marshall and full time work at the quarry for 1886 was underway.  

Marshall’s Masterpiece: The Stegosaurus

It Wasn’t the First

The Stegosaurus that is the focus of this chapter was not the first Stegosaurus found at this quarry.  The first Stegosaurus at this quarry was found in 1884 by Marshall’s crew in the western part of the quarry. This dinosaur was identified as Stegosaurus armatus but later on the species name armatus was discarded.  

The Stegosaurus that is the focus of this chapter was first mentioned in early August of 1885.  Little bits of bones were embedded in the the lower part of 20 feet high cliff wall. The location was very close to where Ceratosaurus had been excavated in the fall of 1883 and these bits of Stegosaurus bone were sitting about the same level as the Ceratosaurus.  Marshall had seen enough Stegosaurus bones by now that he was pretty sure about these bones. He even speculated where the majority of the skeleton would be found. 

Marshall made a quarry drawing shown to the right in his August 10,1885 letter showing where he was seeing Stegosaurus bones. The little o’s along the edge of the cliff wall and the letter F was where he suspected the Stegosaurus might be.  

Plates and Ossicles

Marshall Felch wrote to Marsh on the 27th of October, 1885 stating that the bones he was finding definitely belonged to Stegosaurus.  He described; “great numbers of dermal plates…one large spine…strong curved…and also the little clusters of small bonesin reading up the papers on Stegosaurus – I could find no mention of this particular feature – and did not know but what they might have been missed, or overlooked in collecting, as they would be hard to find in anything but hard firm rock like ours”. 

Charles Gilmore analyzed where these bony scutes (ossicles) were found;  “they covered the sides of the neck from the base of the erect plates downward, scattering, if at all, on the ventral (underside) areas”  Gilmore also commented on the large dermal plates noting;  “ This feature has been the subject of considerable speculation and discussion among vertebrate paleontologists..this specimen (no. 4934) the plates of opposite sides are not arranged in pairs but those of one side alternate with the other”. (Gilmore 1914)

Ossicles discovered by Marshall  shown on plate 22 to the left (Gilmore 1914)

12,308 Pounds of Stegosaurus

Marshall and his crew proceeded judiciously excavating the Stegosaurus. He wrote to Professor Marsh on December 9, 1885; “We have 29 boxes in town, and shall have 6 or 7 more when all are packed. The work is now complete up to where all the rest ahead, appears to be in much better and firmer rock than where we have done the most of our work this season.”  

On Christmas day 1885, Marshall wrote; “I shall expect to receive orders from Maj Belcher by tomorrow or next day to ship the boxes, 35 in all, and then I will go to work writing up on their contents.”  Two days later he wrote; “The total weight of the 35 boxes is 12,308 pounds.”  

Marshall elaborated On February 11, 1886 about the Stegosaurus stating; “Skeleton No. 11 the last Stegosaurus found – lay mostly on the marl bed – under Sk. 9 and the other bones.”  Sk 9 will be repeatably be referred to over the next two years, apparently a large unidentified sauropod that may have been Haplocanthosaurus or Brontosaurus (Apatosaurus). 

On March 17, 1886, Professor Marsh wrote; “You have made us all happy by sending in Group Z(?), Sk 11, complete skull (or nearly so) of Stegosaurus, what we have been hoping and praying for, for years. It comes just in time to be of the most use, as we are just starting in on a restoration. Although badly broken, nearly all the pieces are here, with lower jaw in position.”

Never fully satisfied Marsh went on; “Now get us a hind foot to go with it and we will let up on Stegosaurus. I hope we shall find one with this skeleton, – also something to tell us how the plates and spines go.”

Stegosaurus stenops skull by Charles Gilmore on the right. (Gilmore 1914)

Marshall responded to Marsh’s compliment on March 25, 1886; “I am glad to know that you have found the long hoped for Skull of Stegosaurus – and that it is in as good condition as it is… It is a wonder, any of this skeleton has turned out as well as it has – for in our work in ’83 when … we worked clear up, and on to this skeleton in several places – and only left off – within a foot or so of this group that had the skull.” 

Cutaway view of Stegosaurus skull on the left, plate 8 (Gilmore,1914)

Under the Nose of Ceratosaurus


Four months later on June 17, 1886 Marshall wrote; “In regard to the other fore leg – I don’t believe it is here – for I took out and sent the humerus in 1883 – as will be seen by looking on the quarry map of that year. It lay almost directly under the nose of Ceratosaurus and but a few feet from where we now are – and must have belonged with Sk. 11 as no other bones of Stegosaurus but Sk. 11 have been found in this division of the quarry.  

“An Armor Plated Vessel”

On March 25, 1886 Marsh described how the plates may have been connected to the Stegosaurus; “It was the position of this plate that gave me the idea – that the top of the plate rested on the top…Plates laid on over such a frame work – supported by those strong curved ribs would make a good design for an armor plated vessel.”

Its logical Marshall could have thought this because of Charles Gilmore’s description of the plates in 1914 as the skeleton was being prepared;  “The dermal plates, which in life stood erect along the back, are present to a point back of the pelvis and are retained in the rock in their mutual relations. The eleven plates forming the armor of the anterior part of the animal are turned back in under the body and neck, forming a continuous sheet of bone upon which the anterior parts of the skeleton lay.” Gilmore didn’t suspect this was the position of the plates when the dinosaur was alive, simply that is how they were initially found by Marshall.  The major anatomical question was were they in pairs or did they alternate. 

Plate 14 below showing plates that Marshall excavated. (Gilmore, 1914)

Marsh: “With Some Impatience” 

Marsh wrote on the 18th of May; “don’t uncover the vertebrae very much and especially don’t disturb the plates. I rather not know than to have the blocks marred or cut so that any bone would be injured or its connection lost with those around it.”  In a second letter that same day Marsh wrote; “It is very important to follow on from this point, and get all the rest of the skeleton.”  

On the 11th of June Marsh wrote; “We find that one fore leg and foot of Sk 11, is nearly entire, (left) and you must have the other (right) in the quarry.”   Marsh can’t help but point out a problem though;  “This one (left) has only 4 toes, the thumb being lost.”   

Two weeks later Marsh wrote; “We have found the other fore foot of Sk 11 curled under the first one, but with the toes scattered.”   Marsh continues pressuring Marshall to work harder;  “Don’t let anything prevent our securing all the rest of Sk 11 in full as good order as the part we have. It is our last chance as the plates of the volume are nearly finished.” 

Marsh wrote again on the 11th of July;  “we are waiting for the rest with some impatience. Please do not try to uncover any part that you can send in the rock, and keep the connection. We can cut every bone out here.”

Marshall: “The Only Safe Way”

Marshall explained in great detail the quarry location of the Stegosaurus along with their work plan on the 18th of April, 1886:  “there is but one way to go on – the same as for the past two years – to work with the natural seams – take all along clean across the face of the quarry – good bad or indifferent, old and new as we come to it – any other method is liable to work ruin to many specimens as in the first seasons work. … I know this method is terribly slow and tedious – and half of our work has to be spent on bones that will probably be of no use whatever – but it is the only safe way.   

About a month later on the 16th of May Marshall wrote what his assistants were doing; “they have a lot of broken bones that they are hardening and pasting to make it ‘hard as a marble slab'”.

On the 30th of July, Marshall wrote;  “We have done no extra work with chisels – none whatever – except in getting points of separation – or where it was necessary in trimming off waste rock.” 

It must have been painfully frustrating to explain their work procedures and receive what felt like unwarranted scrutiny. 

Quarry Drawings and Maps

Marshal had developed an ingenious method for excavating the Stegosaurus so that it could be relatively easily laid out as it had died and prepared at the Peabody Museum. The methodology was relatively simple.

As the block was being removed,  he would make markings on the block so that it could later on be placed back exactly as it was found.  A group of fossils such as ribs or a section of vertebrate that might be in three blocks were also labeled to assist preparators back at the Yale Peabody Museum, for example block 3, group 4. Marshall documented his work and prepared detailed descriptions including drawings and maps in letters. Marshall also made special markings near particular bones or fragments where he wanted to point out something specific.  

Once a block was removed, he laid it out on the low table under the shade cover in the way the block was found. When he was ready to do a shipment he would identify which blocks or groups went into which boxes and then carefully label the boxes and identify what was what in his letters.   

This system was an outstanding one but Professor Marsh and his team had difficulty with it. Marshall could not understand the problem until he received a letter from Professor Marsh on the 19th of January in 1887; “We are working on Sk 11, but as we have only room to lay out one point at a time we find some trouble”. 

Marshall responded on the 2nd of February;  “If only you had room to spread out and keep matched up one or two groups ahead of the work there would not be much trouble-but as it is the next best thing in order is a careful study of the diagrams-not only separately but collectively.” 

The Peabody Museum had been opened in 1876 but by 1886 it was overflowing with stacked boxes of specimens crowded into every spare inch.  There was not room at the Peabody to lay out a skeleton in order to work on it so the preparation team did the best they could given the limitations in work space.  This was not an issue when the specimen was moved to the National Museum of Natural History and Charles Gilmore and his assistants had plenty of room work. 

The Letters

In the chapter entitled “Rejoicing in Four or Five Languages” the introduction included a description of the letters written by Marshall Felch that had been found at the Yale Peabody Museum along with the letters Professor Marsh wrote that were found at the University of Utah. There is a total of about three hundred or so. Surprisingly there were ten letters written by Marshall Felch that had been removed from the Yale Peabody Museum. These were specific letters written in 1886 and 1887 that included all the detailed notes, maps, and diagrams on the excavation of key dinosaurs, most notably the Stegosaurus. 

 The crew at the NMNH obviously looked through all the letters written by Marshall Felch and decided to take specific ones that they felt would be most advantageous in working on the fossils they had received, most notably the Stegosaurus.  

Excavating a Stegosaurus: A simple guide

Remove about 15 feet of overlying hard rock down to the bone beds. Use dynamite as needed. 

Do this no sooner than a month or two before you are planning to excavate to minimize weathering within the bone beds. 

The exposed bone bearing bench contains two main bone bearing layers. The Stegosaurus layer will be in the lower bed and it will also contain other types of dinosaur bones.

Professionally remove the upper layer a little at a time doing all the same things as you would with the Stegosaurus layer.  

Generally work your way across the bench from left to right (a run) removing blocks and taking advantage of natural north south. Natural seams (joints) in the rock provide a ready made “backcut”. 

Your goal is identify as much as you possibly can but the bones in the rock are only faintly visible. With training and practice you can learn to identify logical groups of bones (i.e. leg bones).  Use glues and/or paste to solidify any exposed bone. 

A block is something that can be lifted by two people and moved, but in a few places where there is a conglomeration of bones where you may need to take out larger blocks to prevent destroying the skeleton.

Label each block noting how it connects to adjacent blocks and any other markings such as particular bones you want to note. 

Move the block over to the low table and place in the same order as it came out of the quarry.

Take notes and prepare drawings, diagrams, and sketches as needed to assist with eventual preparation of the skeleton at the museum. 

Build custom shipping boxes. Provide clear instructions on what blocks are in what boxes in letters and include any diagrams or other materials to assist preparators in the letters and in the boxes. 

Periodically drag boxes by sled down to the two track road optionally using a horse, load onto a wagon and haul to the train station until you have a full shipment ready to go. 

These directions are a complete oversimplification of what you will actually encounter.  Don’t forget that while you are working the sun will be intense and gnats will be in your eyes and ears and after your shipment arrives at Yale you will receive lots of complaints from a college professor. 

The excavation of the Stegosaurus was just getting underway at the time the map below was prepared. Marshall included the quarry map with one of early 1886 letters.  This map was constructed largely from memory as pretty much everything Marshall produced was sent off to Marsh. 

The Pelvis

The pelvic area is mentioned at various times in Marshall’s letters.  On the 27th of March 1886 Marshall wrote; “If the sacrum is in position with the center of the pubis and illium – it would be somewhere from two feet to thirty inches from the first dorsal in the face of the wall up to the sacrum.”  On June 8, 1886 Marshall wrote: “you will find when you get the rest, that all around the pelvis the bones are massed in more closely even, than they were in group 5 of this skeleton,”

On July 4, 1886 Marshall reiterated the complexity of the bones in the pelvic area; “we find a mass of bones as badly crowded as in the layer above. This last section comes directly under where the sacrum – pelvic – leg bones – and the first of the anterior caudals lay – and we find more leg bones, plates, spines, and some foot bones.” 

On the 30th of July Marshall discusses two large blocks containing pelvic material that will be prepared for shipment;  “Two blocks in 11 will weigh several hundred pounds each – and I had to use 2 inch plank to make the boxes strong enough to hold them.”  

Almost thirty years later Charles Gilmore wrote; “The pelvic bones are all present, though slightly disarranged; the ilia, however, remain firmly ossified with the sacral vertebrae and show plainly the great breadth of the hips.” (Gilmore, 1914)

Articulated left fore foot of Stegosaurus stenops shown as found by Marshall Felch.  Drawing by Charles Gilmore (Gilmore, 1914)

Professor Marsh Pays His Last Visit

In the latter part of September and early October of 1886, Marshall continued to describe bones from multiple skeletons that were mixed up together as he was excavating. Although Marshall understood much more clearly what was going on at the quarry than anyone anywhere by this time, it was probably of some assistance that Professor Marsh stopped by and paid a brief visit sometime in mid September.  It was the last time the Professor would ever visit the old quarry and the last time he and Marshall would ever meet. Marsh and Sadie Felch would meet one additional time. 

Marshall wrote on the 26th of September; “bones of another skeleton mixed up with the spines of No. 11 – and on the left side what appears to be as good a foot as Allosaurus – the bones…showing up at every break = from the largest metatarsal to the smallest bones – and at one point a claw”

On the 26th of October Marshall wrote; “we shall take in the last of this lot with Sk. 11 – 26 boxes in all – tomorrow… This makes all of Sk. 11 that we have out.”   The majority of Sk. 11 (Stegosaurus stenops) was removed by this time although some additional bones would be uncovered over the next year

Professor Marsh wanted a complete skeleton from tip of the skull to the tip of the tail but he was not satisfied. In all likelihood, Marshall found most if not all of the skeletal material that was there to be found.  There were enough animals ranging from crocodiles to small dinosaur predators around 152 millions ago that when the Stegosaurus died some scavenging of the tail and back legs was probable. 

Articulated cervical vertebrae of Stegosaurus stenops excavated by Marshall, fig. 16 by Gilmore below.  “The vertebral column is largely intact and to a great extent articulated—at least it is so little disturbed that the axial skeleton appears to be complete from the tip of the nose to the seventeenth caudal.”  (Gilmore, 1914) 

I Came Near Going Off

On September 7, 1885 (about the time Stegosaurus stenops was discovered) Marshall suffered a leg injury that would not heal.  He wrote: “and though the injury was so slight that I paid but little attention to at first, it in a few days got to be quite serious. Wednesday of the past week I had to get a surgeon to attend it, and he pronounces it an indolent ulcer  and commenced a treatment which is bringing it back to life again – and I hope soon to be around again.”  In his pension testimony Amanda stated that; he had a large boil on outside of left leg.  I poulticed it and after it broke the flesh began sloughing off.  Brought him to Dr. Dawson who said that is a bad looking leg”.  Both of these incidents may have been at least partially the result of using a mercury based salve in use at the time. 

On January 20 1886 Marshall wrote; “I have been quite ill for sometime, and feeling a good deal depressed about matters generally.” On the 31st of January, 1886 Marshall wrote: “I have been so ill and miserable for the past month that I could not do anything, but will try and figure out what you need soon.

Marshall experienced this range of health issues during the year but at the end of the year he went down.  On January 23, 1887, Sadie Felch responded to Professor Marsh for her father stating he has been; “quite ill  requests me to say as soon as he is able he will look up the matter for you.”   Marshall must have been well enough to respond himself on February 2, 1887 writing; “I have been bad off for the two weeks with my old trouble of neuralgia of the heart, am as yet hardly able to be up.” The first two pages are missing from Marshall’s  letter on February 21, 1887 but there a PS at the end of the letter that was preserved; “I am having rather a serious time this winter – and it has been almost five weeks since I was out – have had two attacks since my last in one of which I came near going off.”  

A Post Mortem Diagnosis

The skin lesions were probably the result of using mercury salve, in common use at the time. The sharp pains in his chest were probably the result of improperly healed ribs damaged at the same time he fractured his neck vertebrate after being thrown from a horse during the Battle of Cedar Creek on the 19th of October, 1864. The heart problems he had experienced before the Civil War are best described by Amanda when testifying during his pension application on his behalf in 1888; I place my hand on his heart and it was beating very hard.  I called it a “tearing” feeling. No, the Dr. did not say his heart was affected.  He made me get up one night and open the window for air, said he couldn’t get his breath.” Most likely this was a heart valve regurgitation issue, possibly the mitral valve. It doesn’t appear that Marshall ever had a long term alcohol or opioid problem but he may have taken either mercury based calomel or little blue (mercury) pills making some of his symptoms worse. All of these things were in combination with fairly severe PTSD. 

Digging up dinosaur skeletons in a site like this is hard work, particularly when you consider the heat, cold, wind, gnats, and lack of shade.  Marshall likely spent most of his days working at the quarry and at night he worked by lamplight putting together letters.  This kind of work is something that can be done fairly well over maybe 3 or 4 months per year but Marsh was pushing him to work not stop. The quarry was highly productive and Marsh was very demanding. The reality was that there is only so much an injured and ill Civil War veteran could do.  

Like the Stegosaurus he was excavating, Marshall had been driven to exhaustion.  

Every Hour is Precious

The excavation of the Stegosaurus was largely complete by December of 1886 but work would continue in the field as well as several letters back and forth where Marsh was having difficulty and Marshall was responding to questions.  Perhaps it would have saved a lot of back and forth letter writing if Marsh had paid for Marshall to come to New Haven and answer questions but such an offering was no longer on the table.  

On December 15, 1886 Professor Marsh wrote; “We have come to grief with Sk 11, and I write for help…. Can you help us out? If so, please do so at once.”

As soon as this letter arrived, Marshall responded on December 20, 1886 providing detailed descriptions and information but concluding: “There can be nothing done toward putting groups together without the diagrams-for in them I have tried to give all the explanations necessary-and what they do not give I can add very little too new-as they are the main history and record a I work along”

A few weeks later on January 19, 1887 Marsh wrote; we seem to need is an outline sketch of how the groups lie, and about how the beast Sk 11 runs through them… every hour is precious in making plates for the Volume.”

About the time Marshall was unable to hardly get out of bed he again responded on February 2, 1887 with another detailed description and also providing; “an outline showing as near as I can remember the position of the groups in SK.11” 

Marsh wrote again on the 10th of February; “I am very anxious to find the hind feet (or one of them), and also to get the position of the plates and spines” 

It should have been apparent by now that although the Stegosaurus was remarkably complete, a specimen considered by Gilmore to be “the most perfect specimen of the genus yet discovered” it wasn’t perfect and short of a Rhino being suffocated in a volcanic ash flow twelve million years ago such as at Ashfall State Park in Nebraska, perfect preservation in a river system was pretty much not an option.   

Marsh, being Marsh, expressed disappointment that both hind feet would be missing.  Marshall never gave up trying and once again did his best to assist Marsh. On the 27th of February, Marshall expressed dismay that both hind feet were missing and provided Marsh some boxes to check. 

Over the next few months discussion of the Stegosaurus gradually subsided and other dinosaurs including Diplodocus became the focus of the quarry story and thus, this is where our chapter comes to closure.

Above is a picture I took of the pelvic region looking back toward the tail area during one of several visits by JoAnn and I to the National Museum of Natural History over the years.  Beginning in 2014 and ending in the summer of 2019, the Dinosaur Hall underwent significant renovations.  JoAnn and I are planning a trip back east for the fall of 2019 to see what happened to the Allosaurus, Ceratosaurus, and Stegosaurus. 


Evanoff, Emmett, and Kenneth Carpenter. 1998. “History, Sedimentology, and Taphonomy of Felch Quarry 1 and Associated Sandbodies, Morrison Formation, Garden Park, Colorado.” Modern Geology 22: 145–69.

Foster, John Russell. 2007. Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Bloomington: Indiana University Press.

Gilmore, Charles W. 1914. Osteology of the Armored Dinosauria in the United States National Museum, with Special Reference to the Genus Stegosaurus,. Smithsonian Institution, Bulletin 89. United States National Museum: Govt. print. off.

Next Chapter: The Hands Whoso Beauty Was Duty Done

After 1887 Marshall’s days as a dinosaur excavator continued for another three years but from a practical standpoint were over.

Marshall and Amanda apply for and receive pensions for their Civil War service and both go home to Vermont for a visit.

Amanda unexpectedly dies on New Year’s Eve 1893, about the time she becomes known for her service and an inspirational figure to other women.