George Gaylord Simpson had youthful ambitions to become a man of letters, but a geology course at the University of Colorado awakened his interest in bone-digging and eventually led to his following that career. In 1922 he transferred to Yale, where he completed his undergraduate work in 1923 and received his doctorate in 1926. After a year abroad as a National Research Council fellow, he came to the American Museum as an assistant curator in 1927, where he has remained ever since, except for a period of military service in 1942–1944. He became Curator of Fossil Mammals in 1942 and Chairman of the Department of Geology and Paleontology in 1944. He is a fellow of the National Academy of Sciences and of the American Philosophical Society, president of the Society for the Study of Evolution, and past president of the Society of Vertebrate Paleontology. He has written more than 200 scientific articles and books. In 1934 the field diary he had kept of his experiences in Patagonia as leader of the first Scarritt Expedition of 1930–1931 gave fruit in his lively and fascinating book, Attending Marvels. —Ed 
Three currents of history meet at the corner of 13th and Cherokee Streets in St. Louis, Missouri. South of Cherokee, where 13th does not run through, there is now an immense shoe factory. On the northeast corner of the intersection, there is a large but apparently rather plain brick house. The northwest corner is a lot with only one small structure, which looks like a one-car garage. Each of these buildings is more than it seems to be because each has a historical significance. The shoe factory was formerly a brewery: it recalls a current of history that started in the Rhineland, more than a century ago. The house turns its plain side to the street but when viewed from the east, within its own spacious grounds, it is seen to be a stately mansion with a graceful, pillared portico: its history traces back through the De Menils and the Chouteaus to the pioneer days of the Mississippi. The apparent garage is really the entrance to a cave that rambles beneath the surrounding buildings: its history is the most ancient of all, and in it are buried animals that lived before man ever saw the site of St. Louis.
Our introduction to this convergence of history at 13th and Cherokee Streets began with a letter. Lee Hess, a pharmaceutical manufacturer in St. Louis, wrote to say that he had found some bones in the cellar of a brewery. Would the Museum be interested? Many such letters come to a curator’s desk. Nine times out of ten, they do not lead to anything of value, but we always follow them up as far as possible because the tenth letter may be a clue to an important scientific discovery. We wrote to Mr. Hess asking him to send some of the bones so that we could determine their possible importance.
The bones sent to us had been considerably broken by the workmen who found them, but when we pieced them together in the laboratory we found that they included a skull of an extinct peccary, Platygonus compressus by name. Now, Platygonus is not a particularly rare fossil. Its remains had already been found in many places throughout the United States. For instance, 22 skulls (12 of them nearly complete) had been collected for the United States National Museum in a cave near Cumberland, Maryland, 5 partial skeletons had been found in a peat bog near Belding, Michigan, and 9 nearly complete skeletons had been discovered at Goodland, Kansas, in the clay-pit of a brickyard, and sent to the University of Kansas. One of the Kansas skeletons, obtained from the University by the American Museum of Natural History, was restored and mounted in a lifelike pose and has been exhibited here for years.
In spite of these and other previous discoveries, we became quite excited about the bones from St. Louis. Platygonus had never turned up in a beer cellar before, and extinct animals are rarely found in the heart of a great city. How they came to be there was a mystery worth solving, and we resolved to go to St. Louis and try to clear up the mystery with a little geological detective work. I wrote to Mr. Hess asking whether more bones remained in place and whether we could come out and investigate the find. His reply assured us that many bones remained to be excavated and cordially invited us to study the occurrence. In a few days George O. Whitaker, of our fossil vertebrate laboratory, and I were off for what turned out to be an unexpectedly fascinating rendezvous with history, ancient and recent.
Mr. Hess met us in St. Louis and drove us immediately to the De Menil mansion, the historic home at 3352 South 13th Street. This house, unoccupied but restored by Mr. Hess with sufficient modernization for comfort, was our camp throughout our stay: a camp such as a bone-digger has seldom enjoyed in his wildest dreams of luxury. Before we were through, it was also our bone laundry, shellackery, and packery. Here we dropped at once into an atmosphere of old St. Louis of the pioneer days before the Civil War. The house was originally built in the 1840’s by Henri Chatillon, a western guide and hunter of that period. In 1854 it was purchased by Dr. Nicholas N. De Menil, and in 1863 he enlarged it by adding several spacious rooms and the magnificent portico on the east side, overlooking his large garden and the slope of Arsenal Hill down to the Mississippi.
Nicholas De Menil, who had come to America on a visit (which proved to be life-long) in 1833, was a physician who established the first successful chain of drugstores in St. Louis and became one of the aristocrats of that growing center. He married Emily Sophia Chouteau, linking his family with the real pioneers of the region, for she was the great-granddaughter of Marie Therese Chouteau, the first white woman to settle in St. Louis and still revered as the mother of that city.
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Alexander De Menil, son of Nicholas, lived in the house throughout his long life. By the time he died, Arsenal Hill was no longer a swanky residential district but had been overgrown with smoky factories and surrounded by slums. His heirs chose not to live there, and the property finally passed out of the family when they sold it to Mr. Hess, almost a century after the family acquired it. Like his father, Alexander was a physician, but he was also interested in literature and became a poet of local renown. Among his voluminous productions is a rather quaint but forceful defense of his great-great-grandmother, the famous Madame Chouteau. (She left her husband in New Orleans because of his cruelty to her and formed an irregular union with Laclede, who became the founder of St. Louis; her solution of a marital problem when divorce was impossible was approved by her contemporaries, but became a worry to some of her descendants.)
We often thought of these vanished occupants as we roamed through the house or rested on its spacious balconies and watched spring come to the garden. If, however, the ghosts of the Chouteaus and the De Menils roamed through the house at night, we never knew it, for we slept soundly after our hours of bone-digging. Ghosts still more exotic might conceivably have troubled our slumbers. The fascinating hodge-podge accumulated by Mr. Hess with a view to future exhibition included a reconstruction of a Damascus palace with its furnishings. After display at the St. Louis fair in 1904, these oriental trappings had been crated and stored until recently when our host acquired them and piled them into the De Menil house. Thus it happened that our library included an Arabic Bible, along with Hedin’s My Life as an Explorer, the Catholic Directory, Boccaccio’s Decameron, and How to Develop a Winning Personality. Pending the availability of more space and the sorting of all these treasures, our quarters were furnished in a medley of styles in charming confusion. Tubular metal modernistic chairs jostled a mid-nineteenth century chaise longue, over which was thrown a vivid Mexican serape and beside which was an old Turkish tabouret of ebony inlaid with mother-of-pearl. The introduction of our prehistoric peccaries struck no jarring note but seemed only to complete this remarkable mixture.
It was, after all, the prehistoric peccaries that had called us here and that claimed most of our attention, but even these brought us into contact with history as well as with pre-history. Unrest in the Rhineland well over a century ago was one of the influences that led to our journey to St. Louis last March and to the exhuming of these ancient remains. It was in the 1820’s that one Gottfried Duden came to the Mississippi Valley to spy out the land for his German neighbors. Here in St. Louis he found several caves in the limestone underlying the city and he reported that the site was propitious for breweries. Before the coming of artificial refrigeration, successful brewing on a large scale required natural repositories where the temperature was constant and low throughout the year. These caves, which retain a temperature near 55° regardless of the weather outside, were ideal for the purpose. Rhineland brewers migrated to St. Louis and converted the caves into storerooms for their lager. It was one of these immigrants, Adam Lemp, who cleared out the cave at 13th and Cherokee and built his brewery above it.
Toward the end of the nineteenth century, air-conditioned storehouses made the caves unnecessary, and they were abandoned by the brewers. One or two were converted into underground beer parlors and places of amusement: Uhrig’s Cave was such an establishment in the gay 90’s and is nostalgically remembered by St. Louisians. But the cool, dark dampness of the caves, so suitable for beer before it is drunk, seemed to depress the customers after they drank the beer. “Uhrig’s Cave” became an open air theater above the actual cave. The cave itself enjoyed only one more brief flare of fame when a large distillery was discovered in it during prohibition. The other caves were closed, their entrances walled up or blocked with debris, and eventually they became vague memories. The Lemp Brewery went out of business during prohibition, its buildings were sold to the International Shoe Company, and its cave, the Cherokee Cave, was forgotten until Lee Hess recently conceived the idea of reopening it as a site of historical and geological interest.
When we arrived, we took only a quick glance at the noble De Menil mansion (“our puptent,” George called it), and then hurried down into the cave. A circular, bric-lined shaft about 85 feet deep had been reopened and a spiral iron staircase installed. At the foot it opens into a long series of storage rooms, once full of lager beer but now dismally empty. The rooms were formed simply by clearing out a natural cave, a former underground river channel within the solid limestone, and by dividing it by masonry walls. The first room at the bottom of the shaft still bears traces of its use for private theatricals and parties by a gay blade of the Lemp family who took it over when the beer was moved out. Across one end he constructed artificial scenery made of wire screen and plaster. The scenery represents a fair imitation of the wall of a cave; this hiding of a real cave wall behind an artificial cave wall is one of the touches that made us feel at times as if we had stepped into Alice’s Wonderland. There are still remains of the crude but serviceable floodlights used to illumine this scene.
The cave extends in an easterly direction for some 200 feet beyond this “theater.” There it is joined by another channel, coming from under the former brewery to the south, also cleared and converted into storage rooms. At the intersection is a concrete-lined pool, presumably used as a reservoir in the old brewing days and reputedly used as a swimming pool in the later (but now also old) days of theatricals and parties, although we thought that a party would have to be very stimulating, indeed, to tempt us to plunge into those Stygian waters!
This was the end of the cave so far as the brewery was concerned. It terminated here with a masonry wall. To see where it went beyond, Mr. Hess had the wall broken down with a hydraulic jack and was disconcerted to find that although the cave does, indeed, continue, it was almost completely filled by a deposit of stiff, wet clay. This made it impassable for anything much larger than a rat. He had workmen dig a narrow passage in the clay, following the ancient channel of the cave. Within 20 feet from the wall it turned to the left, northward, and had, at the time of our visit, been followed in that direction for some 200 feet farther, with no sign of ending, or of coming out to the surface, or of joining another, adjacent old brewery cave (the Minnehaha Cave) with which Hess hopes eventually to make a connection. The point where the cave turns is almost under the porch of the De Menil house, where we used to relax at lunch or in the evening, 40 or 50 feet straight above our diggings.
A more talented and imaginative writer might contrast these superposed scenes in a sort of allegory. In the upper world it is spring. The air is warm and balmy, and the sun is shining. The grass is green and sprinkled with violets. Bushes and trees are in bloom, and innumerable birds are setting about their seasonal loves and labors. The caretaker’s pretty baby girl toddles about, learning to walk. The world of life is developing its future in a scene just old enough to be leisurely and pleasantly mellowed.
In the lower world there are no seasons. The motionless air is always cool but never cold. The humidity is always near 100% and nothing is ever quite dry. The white limestone ceiling is dewey as if perspiring quietly, and water drips slowly from the tips of the scattered stalactites. The water is limpid but it carries in solution minute quantities of lime, the slow, imperceptible precipitation of which through the ages has formed the stalactites, stalagmites, and cave onyx, all forms of what has appropriately been called dripstone. Yellow lights illumine a scene that has never known the sun and make temporary islands of light in a sea of absolute darkness that has been lightless for hundreds of thousands of years. Smeared from head to foot with yellow mud, workmen slide along the narrow passage, digging out the sticky clay, penetrating still farther into the mysterious entrails of the earth where man has never been before. In spite of this rash intrusion, the strange scene seems as ancient and timeless as a tomb. And it is a tomb, a place of mass burial, sealed away as a monument of the dead past, before the first Indian ever hunted a deer along the top of the hill inside which it lies.
That filling of clay is an exasperating and expensive nuisance to the men who want to reopen the old cave channel, but it is a delight to the bone-digger. It was in this clay that the workmen found the bones that brought us to St. Louis, and we began finding more bones as soon as we dug into it for ourselves. In the week that we were there, we found too many bones to count, but we guess that we excavated between 2,000 and 3,000 of them, some almost too small to see while others were large, complete skulls.
As we dug bones, we began our detective work. What the bones are is perhaps the least part of the mystery, and their identification had to be done back in New York, anyway, where we could study and compare the bones at our leisure. Here the problem was how the bones came to be here, in the core of Arsenal Hill under the De Menil house. Some clues are still missing and a more fortunate detective than I may prove someday that I am wrong, but we did soon find enough clues for a tentative solution of the mystery.
As Clue No. 1, there is the cave itself. By that I mean the long, branched, channel-like cavity in the limestone, regardless of the fact that it is or has been nearly filled up with clay. It averages 20 to 25 feet wide, with solid limestone walls and ceiling. We do not know how long it is, where it comes from, or where it goes to: important missing clues. We do not even know how deep it is or what the floor is like, because as deep as anyone has yet dug (12 to 15 feet in places), the bottom of the clay has not been reached.
Clue No. 2 is the clay, or rather, this is a series of clues, because the clay proves on investigation to be complex and to include several distinctive superposed layers. The lowest layer visible, as far as it has been excavated, is massive, yellowish gray, and somewhat gritty. We found no traces of bone in this. At its top in some places but not in all is a layer of dripstone (cave or “Mexican” onyx) from which rise stalagmites, buried by the overlying layers of clay. The next higher clay layer, sometimes absent but in other places two feet or more thick, is very smooth and fine, without grit, and is deposited in thin, horizontal layers. There are no bones here, either, except occasionally right at the top where they probably sank in from above when the clay was less compact. The top of this is sharply distinguished from the overlying bed but it has no layers of dripstone so far as we saw. Next higher is a bed of clay quite variable in thickness but averaging 18 to 20 inches, also fine and plastic, but without layers and containing many scattered chunks of limestone and of dripstone. Almost all the bones are in this bed of clay, which we called “the peccary layer.” Above it there is occasionally, but not usually, a thin layer of dripstone. At the very top is a bed, usually less than a foot thick, of relatively loose, granular, earthy clay. In places it fills holes extending down into the lower layers. A few very small bones were found in this bed. In some places where there is a small unfilled space above this top layer there are small stalagmites on it, and where these occur they are usually set on small plaques of dripstone.
Our major clues are the bones themselves, not only because of what they are but also because of how they occur. As I have said, almost all the bones are in the “peccary layer.” You cannot dig long in any part of that particular stratum without finding bones, but they do usually tend to be more common toward the bottom of the layer. Even when several are found together, they are just piled up at random. No two bones of the same animal are found together. Most of the long bones are buried in a more or less horizontal position, but some are oriented without regard for the natural bedding of the deposit and they may even be vertical. Small, solid individual bones are usually whole, but the longer and more fragile bones are usually broken. We did not find a single complete rib. A few of the bones have tooth marks and had been gnawed before being buried here. Bones of the extinct peccary are by far the most common, but there are also a few bones and teeth of other extinct animals and of some living species in this layer; I will give the list later.
The rare bones in the highest layer tend to occur in a few pockets, scattered but sometimes with the remains of one individual near each other. Except for one or two bones apparently washed out of the peccary layer, there are no extinct animals in this bed and most of the bones belong to small, burrowing rodents.
Those are the main clues. This is my proposed solution, so far as it has yet been carried: The very first thing that left traces here happened so long ago that it is only indirectly involved in our problem of the bones. This was the deposition of the limestone, which occurred in a sea that covered this site about 300,000,000 years ago. Much later, perhaps only a million years or so ago (the event has not been very exactly dated, and it took a long time), the cave was formed. The sea had withdrawn long since and the region had been uplifted gently. Water began to percolate along the cracks and seams of the limestone and as it went, it slowly but steadily dissolved the rock. Eventually it formed a large underground channel which was, and is, the cave. At this stage the cave was free of any extensive deposits of clay, and it probably had a subterranean stream or river at the bottom. This probably reached the surface some distance away and eventually flowed into the Mississippi.
Somehow the exit from the cave became clogged and the clay and silt brought in by streams from the surface, instead of being washed on through the cave and out again, began to pile up in the cave. These sediments eventually filled the cave up to within a few feet of its ceiling. Then for a long time there was no particular activity except the slow dripping of lime-filled water within the cave, developing dripstone deposits here and there on the top of the silt which now formed the floor of the cave. This floor was not even but contained shallow depressions. The next recorded event, which probably occurred during a particular rainy period of the Ice Age, was the filling of these depressions with water, forming within the cave a lake, or a series of small lakes. Tiny, insoluble clay particles were slowly washed into this standing water and they accumulated at the bottom, forming the bed of horizontally banded clay that we found below the peccary layer.
Now came what is for us the great event: the deposition of the bones in the cave. The evidence shows clearly that these animals did not live or die in the cave and it strongly suggests that this was not the first place in which they were buried. The animals probably fell into a sinkhole or fissure somewhere near the cave, perhaps a hole that had been an entrance to the cave but had been sealed off from it by the older accumulation of clay or by a fall of rock. The exact spot has not been found and search for it would not be very hopeful now that the whole region has been built up as part of a great city. The bones of many animals, hundreds certainly and perhaps thousands, piled up in this sinkhole or fissure and were buried there in mud and clay that washed in over their bones. Then the accumulation—clay, bones, and all—was somehow washed into the cave. There are several ways in which this could have occurred. Perhaps the most likely is that the sinkhole or fissure filled up with water above the clay and bones, that this water found an outlet into the cave, and that it suddenly flushed the whole deposit into the cave and spread it out over the older clay deposits of the cave. The nature of the peccary layer in the cave suggests that it came there rapidly, perhaps in an hour or two—one dramatically rapid event in a sequence where most changes can only be measured in terms of thousands or hundreds of thousands of years.
After this sudden change, things quieted down again. A little more clay was washed in from time to time. Rodents occasionally wandered into the cave, rooted around a bit in the top clay, and died there. These later events did not matter much so far as our interests go, until the final event of the reopening of the cave by man. It is surprising that the discovery of prehistoric animals here was delayed until 1946. When the brewery cleared part of the cave, many tons of clay were removed and in this there must have been thousands of bones. So far as is known, no one paid any attention to them. Presumably they were carted off with the clay, dumped somewhere, and buried again: their third burial.
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The bones that have now been recovered and saved for scientific study include all anatomical parts of numerous individuals of the extinct peccary, Platygonus compressus. Both sexes and all ages are represented, from tiny jaws of peccaries newborn, or perhaps actually not yet born when they died, to skulls of big, tough boars. North America was peccary headquarters for millions of years. Numerous extinct kinds have been discovered, and there are two kinds still living in South and Central America one of which, the collared peccary (Tayassu angulatus), ranges as far north as southern Texas, New Mexico, and Arizona. Peccaries are sometimes called “wild pigs” and they do look much like pigs, but the real relationship is not very close. They do not belong to the pig family (Suidae) but to a distinct family of their own (Tayassuidae). True pigs have never been native to the Western Hemisphere.
The living peccaries are rather small animals, seldom over 20 inches high at the shoulder. They usually run in bands and are inoffensive vegetarians, although their sharp, curved tusks give them a somewhat fierce appearance. Some travelers have told horrendous tales of being attacked by large bands of peccaries, but more reliable observers report that they will not attack except as a last resort when they are molested. The normal use of the tusks is to pull up and cut roots for food. Our extinct peccaries from Cherokee Cave had the same habit, because several of the tusks that we found have grooves worn in the sides from rubbing against gritty roots. In fact, these ancient peccaries must have looked and acted very much like their surviving cousins, except that they were about twice as large.
We had hoped to find remains of other animals that lived at the same time as the peccaries, and in this we were successful, but only one of our additional discoveries was particularly striking. Apparently the trap in which these animals were originally buried, the sinkhole or fissure from which their remains were flushed into the cave, was specially adapted for catching peccaries. Few other animals fell into it, but we did find scanty remains of a black bear, a raccoon, and a porcupine, all much like those still living in the region when white men arrived there. The unexpected discovery was an extinct armadillo, related to the recent Texas armadillo but larger. This is an important new record, because St. Louis is much farther north than any other known occurrence of an armadillo, living or extinct. Recent armadillos range no farther northward than Texas, and the only comparable previous finds of extinct armadillos were in Florida.
Both the armadillo and the peccary, also a warmth-loving animal, suggest that when these animals lived there the climate of the region was milder than at present. They may have lived just before or just after the last glacial stage of the Ice Age, for these were times of relative warmth. Aside from this inference, it is impossible to give a very close answer to the question as to how old the bones are. The difficulty is increased by the fact that the bones were not originally buried where they are now found. They may have lain for a long time in their original tomb before being washed into the cave. They are pretty surely more than 20,000 years old, and it is not likely that they are more than 500,000 years old—the interval gives a good deal of leeway. In any case, they are very ancient in terms of human history but are quite young as fossils go.
Hermetically sealed in continuously damp clay since shortly after the animals died, the bones have been unusually well preserved. The marrow and other soft animal matter have decayed and disappeared, but the hard bone substance has not changed at all. The bones were roughly jolted when they were flushed into the cave and many of them were broken then, but even the fragments are strong and fresh and some of the unbroken bones look almost as if they were the remains of last night’s pork roast. This beautiful preservation made the bone-digger’s job much simpler and quicker than it usually is. It was not necessary for us to apply preservatives to the bones immediately on exposure or to encase them in reinforced plaster before moving them—procedures usually necessary with fossil bones. After carefully exposing them on one side, they could immediately be pried out of the clay without damage. The problem of cleaning them was also unusually simple. No slow grinding, scraping, and chiseling to remove the rock in which most fossil bones are buried. We simply soaked them in a wash basin for an hour or two and then scrubbed off the clay with a stiff brush.
With the help of Mr. Hess and the gang of workmen he provided, we developed a mass-production system in our bone-digging. The bones were piled up in boxes as we dug them out, and the full boxes were then taken up to the De Menil house, where we had what we called our bone laundry. Here, in the old kitchen, they were set to soak, and when the clay had softened sufficiently, they were thoroughly scrubbed. The clean, wet bones were then spread out to dry on tables in the dining room. Like fresh bones, they do tend to crack when dry; the fact that they had not been dry for thousands of years is a reason for their exceptional preservation. So the next step in the production line was to paint them thoroughly with thin white shellac and then to dry them again. The shellac soaks in sufficiently to seal all the incipient cracks and forms a transparent protective coating that will preserve them practically forever. Then they were ready for the last step and were moved on along the line into the parlor, where they were carefully wrapped and packed in boxes and barrels for shipment to New York. Between the cave and the mansion, our bone mine, laundry, shellackery, and packery hummed all day and sometimes far into the night. In only one week we had what would ordinarily be a good bag for a whole collecting season. Not only that, but nine-tenths of the bones were all ready for study or exhibition when we shipped them, requiring none of the usually tedious additional preparation in the New York laboratory.
So the mystery of the bones in the brewery was solved and a goodly sample of the bones moved on to the Museum by way of the De Menil house. De Menils and Chouteaus; peccary knuckles and beer; caves and palaces—these were some of the ingredients in a unique adventure in bone-digging. It was a curious mixture, so strange that at times we were hardly sure whether we were awake or dreaming. But as I write these last lines a peccary skull looks at me blankly, reassuring me that the fascinating medley of history and prehistory was real.