The San Angelo Formation and a Look Backwards

Robert Roth, of the Humble Oil Company in Wichita Falls, earlier had given me invaluable aid in understanding the stratigraphy of the Vale and Choza. In 1949 I stopped in to see him at his office, and we went over some of the broad problems of Permian stratigraphy. During this talk, he noted some beds in which Humble Oil field men had found what looked like fossil bone. They were in exposures on the north side of the Pease River in Hardeman County (Figure 6). This was really exciting, for the formation in question was the San Angelo and it was considerably younger than any in which we had found fossils. The tip paid off and began to change the whole direction of our studies, eventually leading to my studies in the Soviet Union. While this new phase of our research was developing, we kept at the lower beds as well. I also took the extensive collections we had from the Arroyo, Vale and Choza and began to synthesize the information.

The Animals of the Arroyo, Vale and Choza

We had fully expected to find distinctly new kinds of animals in the higher beds of the Vale and Choza, but in this we were mainly disappointed. A few new species did come to light, and to one group of primitive animals with the impressive name of captorhinomorphs we added two new genera. A new species of lungfish from Wade's "green sand rock" added to the picture. The changes, however, were subtle as I suppose we might have expected. About that time, my close associate Robert L. Miller and I were delving into the application of statistics to the study of fossils. I knew fossils and he knew statistics, and we traded information. Out of this came a much better appreciation of the meaning of small changes. In this perspective, the information from the higher beds, when integrated with that from the older Arroyo sediments, led to the idea of studying the changes of a whole fauna moving through time, not just its parts alone. The concept was formalized under the model of a chronofauna, a name suggested by Bryan Patterson. The central idea of the chronofauna was that at a given time an array of animal species formed an integrated trophic system with each species occupying a particular position in the food chain. This is a standard ecological proposition. Over time, the species composition of the network might change while the constituent roles remained essentially intact. Within this context, the evolution of the system as a whole and the evolution of the individual lineages can be studied in a realistic and inter-pretable context.

Everything was not, of course, straightforward. A few rare and strange fragments and skeletons of entirely new animals did turn up in beds of the Vale and Choza formations. They did not fit the patterns at all. Some years before, Paul Miller had obtained skeletons of three otherwise unknown animals from a small pocket near the Arroyo-Vale boundary. Near the top of the Vale we found two intertwined skeletons of an early herbivorous pelycosaur, Casea, closely related to one of Miller's animals. One small part of a similar animal turned up in the Choza. Nothing like them was found among the hundreds of other Vale-Choza specimens. At one site a palate with eight rows of teeth was unearthed; at another, part of a large forelimb; and so on. For the time being they seemed mostly destined to pose unanswerable questions, unless our model was completely wrong. Later, as our work carried to still higher beds, close relatives were found, living under very different environmental conditions. During Vale and Choza times another evolutionary pathway was going along, somewhere in the uplands, and our odd fossils appeared to have been washed into the low-lying beds where the two systems came close together.

By the time these puzzles had come to light, but had not been solved, we had pushed our wandering to the uppermost beds of the Choza formation and had encountered sediments formed on the shores of the great Permian inland sea, where red clay-shales and gypsum portrayed an arid climate, born out by the adjacent land sediments. Fossils were absent and the "great desert" seemed to have caught up with our efforts.

The Upper Permian San Angelo Formation

Capping the barren upper Clear Fork sediments, mainly west of the Benjamin-Crowell Highway (Figure 6), were gray-green sandstones and gravels. These beds formed low escarpments and looked to be very unlikely sources of vertebrate fossils (Figure 13). Even after we had opened up some good sites with partial skeletons showing, Professor Romer, who had come over for a visit, assured me, tongue in cheek, of course, that "there warn't no fossils in them beds." He wasn't too far from wrong, for these beds, which turned out to be the deposits of the San Angelo formation, were for the most part barren of fossils and those that did occur were in sediments very different from the ones of the Lower Permian. This difference threw our ways of hunting off until we became attuned to new ways of operating.

Everything we did find, however, was new and exciting. The old water-based ecosystem of the Lower Permian, now gone, was replaced by a full-blown terrestrial system dominated by large herbivores and a smattering of smaller predatory carnivores. While fascinating, another startling development emerged as the study went on. We had begun to overlap in time deposits in the Soviet Union, from which had come their earliest Upper Permian vertebrates. Some of their animals and ours proved to be strikingly similar, so much so that in one or two cases they might be considered to belong to the same species. We had begun to forge a link between the basal Upper Permian of the two continents, North America and Europe. The high Russian deposits overlapped those of South and East Africa in time and animals. The establishment of a fully documented evolutionary sequence from the lower to the uppermost Permian loomed as a possibility. This initiated the chain of events that eventually led me to Moscow.

We started our hunt in the exposures of the San Angelo along the Pease River near the Benjamin-Crowell Highway (Figure 6), as suggested by Robert Roth. This was near the northern end of the San Angelo exposures, which pass underground shortly before reaching the Texas-Oklahoma border. The southern end of the formation was about 200 miles southwest in the vicinity of the city of San Angelo, the place after which the formation was named. The southernmost fifth of the exposures baffled all our efforts to find fossils, but the remainder, up to the Pease River, yielded its treasures, if reluctantly. The sites were separated by river cuts, but on the whole, we were able to get fossils from a more or less continuous line of exposures that formed a band about 160 miles long and five to ten miles wide.

Luck, as usual, played a part in the work. In our first venture into the Pease River exposures, driven there by rains that made the muddier Choza beds unworkable, we turned up fossils after about an hour of hunting. Nick Hotton and I were scanning the rocks not far from the highway when Nick called out, "Hey Doc, I got something here." I was about 20 feet up-slope and hurriedly skidded down to him. He did have something — some teeth of a fresh water shark. While I rooted around, taking them out, he went up to the level I had been working, and 10 feet from where he had stopped me, located part of a pair of jaws! The game of one-upmanship in hunting fossils is always played by prospectors, and here my graduate student, Nick, had one-upped me twice. I had it coming. However that was, the jaws he found were of some animal like none we or anybody else had ever seen before in North America. In the smug vernacular of the pompous of our profession, it was "new to science."

The luck was in getting such quick results, for it was not until a week of fruitless search had passed that we found anything else! If these first bones had not turned up, we might well have quit the San Angelo, considering it barren of vertebrate remains. More did turn up and gradually we extended our searches southwestward, to Little Croton Creek on the Mac-Fayden Ranch; to the southwest of Benjamin, Texas; to the Alexander Ranch near Truscott; and to the Swenson properties not far from Aspermont (Figure 15). Finally, we filled in the middle by working north of the Benjamin-Guthrie Highway. This was mostly done from the camp at Wade's, but gradually the distances got too great for the old Model A Ford. We were able to get hold of a used 1951 Ford pickup truck, more roadable but not as agile in getting over the bad country as the "A." At length, the time spent in running the 35 to 50 miles from Wade's to the collecting sites began to be too great. Reluctantly, I decided to leave Ignorant Ridge and establish new headquarters farther west. For one season we used Truscott, Texas, as a base. Later, Benjamin, Texas, became the center of operations, and with the discovery of a rich deposit some six miles west of Benjamin, along the Benjamin-Crowell Highway and six miles north on mud roads, we set up a field camp at the site which served us for several seasons.


Figure 15. Vertebrate remains in plaster jackets along Little Croton Creek on the MacFayden Ranch, Knox County, Texas. My crew (left to right): Dick Konizeski, who went from digging and shovelling to become Professor of Forestry at the University of Montana, Missoula. Ernest Lundelius, a true Texan's Texan who, returning "home" after a stint to his Ph.D. at the University of Chicago, made great inroads into our knowledge of Pleistocene vertebrates and has become a "wheel" in geology at the University of Texas at Austin. Dick Beerbower, who early prodded me into the consideration of faunas as units, put his agile wits to solutions of intricate paleoecological problems and is now a Professor of Geology at the State University of New York, Binghamton.


It was tough going in the San Angelo wherever we went, for fossils were mostly scrappy and were found almost always one at a time, not in concentrations. One summer, for example, we spent six weeks and came up with eight specimens, mostly-scrappy. So, discoveries north of the Benjamin-Guthrie Highway became milestones. One find of particular importance was made by Jack Kahn, a graduate student in sedimentology, who was out with me in 1955 when we were beginning to explore the beds on the Driver Ranch. He'd been walking the stream cuts south of the North Fork of the Wichita River, while the rest of us were out in the flatter country. Along one arroyo, Jack discovered a layer of sediment about three feet thick, with a concentration of bones that stretched out for some 40 feet! This was what we had been wanting.

From 1955 to 1960 (Figures 16-18), we excavated this area, which I dubbed the Kahn Quarry. About 200 specimens came out of it, some complete skeletons but mostly partial skulls, jaws, limb bones, vertebrae and so on. To hasten the work, we hired a bulldozer four times and got a hold of a gasoline-fueled jackhammer. We made a big hole, finally about 100 yards wide and cut some 50 yards back into the bank, with 25 feet of overburden. From this quarry, and of course other places as well, came a wealth of material that, in some ways, was very much like materials of the same age in the Russian Permian and, in others, very different. It was much scrappier than we would have liked but nevertheless of great value in the reconstruction of the life of these times.

Dying Towns and Houses


People in the small towns of Texas are hard to get to know, but once they are your friends, there is the basis for as fine a relationship as can be. One spring Ralph Johnson and I, following up on work at the Pease River and Little Croton Creek, decided to stay in the little hotel in Truscott, Texas, just west of the Benjarnin-Crowell Highway. Truscott had gone far downhill over the last several years as railroad service diminished and automobiles and good roads shifted the populations to only a few of the many towns in the area. Truscott, once with a bank, hotel, stores and a grain elevator, had seen good days. When I was there, however, the hotel was just holding on and the bank had long since gone. The elevator stayed and later was enlarged.


Figure 16. Camp at Kahn Quarry. The quarry was named after its discoverer, Jack Kahn, sedimentologist Left to right: Herb Barghusen, who retired in 1988 from the University of Illinois Medical School to follow his photographic bent. Bob DeMar, another Chicago Ph.D. and student of Permian amphibians and reptiles, is now professor at the University of Illinois, Circle Campus, Chicago. Matt Nitecki, my long term field partner and "camp boss," who explained me to the graduate student gangs and them to me. Moving from the Walker Museum collections to the Field Museum of Natural History after receiving his Ph.D. at the University of Chicago, Matt became Curator of Lower Invertebrates. Beginning in 1956, and for several years thereafter, the camp was spring or summer "home" for many other graduate students in paleozoology including Jim Hopson, (University of Chicago), Pierre Joelicour (University of Montreal), Dick Sel-tin (Michigan State University), Vernon Swanson (M.D.), Bob Hessler (University of California at La Jolla), Dave Simmons (bone histologist, Houston), and John Donahue (who left vertebrate paleontology for greener pastures).


The church stayed and was strong and the school was maintained — held onto like unyielding defiance of grim death itself.

Figure 18. Left: A nearly complete specimen of Cotylorhynchus hancocki laid out on a table in my laboratory at the Field Museum of Natural History: Right: Matt Nitecki in the "sound proof room" at the Walker Museum, University of Chicago, working on vertebrae of the specimen.

Such towns found a parallel microcosm in deserted farm houses (Figure 19). An air of sad nostalgia and dreams realized, then lost, emanates from a stately crumbling house standing bleakly alone in a field with corn or cotton crowding its thresholds. The sagging shutters once kept out the hot sun and the cold winds of the northers. An added dormer tells of the growing up of the children and a good year with the crops. The tilting, wrap-around verandas once were set with chairs and swings where the cool of the evening was welcomed. Kids trudged down the faint, weedy driveways to hike the miles to school, kicking stones along the mud roads. They grew up, helping with the farm work, using new equipment and techniques, and putting new paint on the old house. Drought, autos, roads and wars, drawing off the young, left the old people on the land. At length, many who were left behind moved to town, close to friends and help. The fields of Texas and Oklahoma are dotted with these memories and, like the towns, they always start me dreaming of what must have been.

Figure 17. Excavating at Kahn Quarry. Top: Orville Gilpin of the Field Museum of Natural History excavating with a gasoline powered jackham-mer. Bottom: Block containing a nearly complete skeleton of the "giant" Permian herbivorous reptile, Cotylorhynchus hancocki. The specimen removed from this block is shown in Figure 18.



Once the hotel in Truscott had been the center for gatherings from the country side at the big family table — eat all you could for a dollar. It was still functioning in 1946. When Ralph and I moved in a few years later, the restaurant was still open, but mostly for short order service. We were then the only paying guests. The town was in the center of an area we wanted to work and we had the idea of putting together a book. The book never came off, but we both developed ideas that appeared separately in publications later on.

Mrs. Jones ran the Truscott Hotel, keeping it open with the help of a few occasional cus tomers such as us and as a meeting place offering coffee, coke and a juke box. Below our room was the restaurant and juke box, and we were regularly regaled by the semi- country western rock tune I can handle that job all by myself. At top volume!


Figure 19. An old, abandoned farm house near Gilliland, Texas, and its weathered and degraded landscaping, telling a nostalgic story of what used to be.


Mrs. Jones knew everything about everyone around. Helping her was a delicate, small and very old black man called Goldie. He took our bags, bigger than he, and carried them upstairs, in spite of our protests. The relationship between Mrs. Jones and Goldie was fascinating. I have no idea how he felt about her for he never talked much except to comment on the weather. Mrs. Jones was ultra-talkative. One evening sitting in the cool in front of the hotel on an old wood bench, after Goldie had left to go to his room, she began to ramble.

"He's gone to his room to read his Bible," she explained. "He is such a good little man, so clean and so religious. He knows his scriptures by heart. Never knew a better man. Isn't it a shame he doesn't have a soul!"

There was no movie in Truscott, but Gary Cooper had left his mark. The kids unconsciously acted out the roles of their heroes, not only Cooper, but John Wayne, Alan Ladd, Jimmy Stewart and Henry Fonda. Late in the day, Ralph and I were having supper in the cafe when we heard the door open. But no one came in. We looked around and standing there was a tall, splinter thin, young man in his late teens, looking the place over. His flat, black hat shaded his slitted eyes as, head still, he shifted his glance back and forth over the room. Satisfied, he walked to the counter with slow, measured steps, eased himself down, pulled out his Bull Durham bag, and went to work on a one-hand roll of a cigarette. With a slight turn of his head, he looked at us with narrow eyes akimbo.

"What'll you have, Billy?" asked Mrs. Jones in her strident voice, cutting the image down to size.

Billy, pulling his tobacco pouch shut with his teeth, shifting his look quickly right and left, replied with a flat, drawled monosyllable, "Beans." High Noon at the lunch counter was never better done.

A few days later the big news broke. A wildcat well had come in near town. A wild flurry passed through Truscott, good times were coming back and the town would rise once more. Knox City, some 25 miles south, already was reviving with some gas and oil. Geologists from several oil companies came on the scene. Most of them, with big cars, stayed in Knox City, connected by a good road. One group of three men, however, stayed in the hotel. We got together for some "geologising" that evening, both figuring on picking the others' brains. We lost. You can't get much from nothing.

"What are we in here?" one asked. He meant, of course, what was the geology all about and, I thought, what rock formation was exposed.

"Well," I said, with a bit of caution, "those lower red beds with the gyp are Choza. You get some sands, kind of gray-green, and then some San Angelo. We are working higher, in the red shales of the Flower Pot (now grouped with the San Angelo)."

"No," came the dazed reply, "you know, what period?"

"Good God," I thought, but didn't say aloud. "You mean the Permian?"

"Yeah. This is Permian?"

These were oil company geologists? All I could figure is that the company must have wanted to get them out of the office. One was a graduate student, on summer pay, but the others, the boss at least, might have looked at a map. Anyhow, everyone in Texas, geologist or not, knows it is Permian in this area. A considerable part of the state forms the famous Permian Basin.

A day later the party boss asked me if there was any unit he could map on. The geology is excessively simple, beds flat and little faulted.

"Sure," I answered. "The top of the basal sandstones of the San Angelo is best." I explained in some detail where to find it.

The next day they were back. Couldn't find it. They found some orange peels where we had eaten lunch, about 100 feet up the hill from the mappable bed. Next day they found us in the field and were happy that they had found a good bed. I never did know if they realized it was the one I had told them about, maybe because I had another shock. Ralph and I had found a fair part of a skeleton, had dug around it, put a plaster and burlap jacket on it, and were hammering long cold chisels under it preliminary to turning it over. The geologists drove up.

"What you got?"

"Part of a big reptile. No head."

"Find it here?" from the youngest, a graduate student.

This stopped me cold. The block- weighed around 600 pounds and was still attached to the ground by a three foot pedestal, giving it the look of a giant mushroom. The instrument man, who was pretty sharp, was embarrassed, and carried it off so I didn't have to answer.

All seemed to end well. We didn't see the party for a few days, but in the evening at the hotel, on the weekend, they were packed and leaving. The boss came over and thanked us for our help.

"I shouldn't tell you this," he said, looking around the deserted lunch room. "It's a company secret, but we got a structure!"

"Where," I asked, and after he had explained, "Great," I lied.

This country has a lot of gypsum under ground. It is soluble and as it leaches out the ground tends to heave or drop forming little basins and domes. Not much for oil prospects. I suppose it was a structure of this sort, but I doubt that the home office was overly excited. As to the wildcat, as so many do, after putting out a few hundred barrels of oil, it gracefully died and Truscott went back to its unrippled calm and slow decline of the weeks and years before.

The hotel didn't last the year, but the domino parlor, where a garage once thrived, stayed, and down the street the church stood firm. A new grain elevator went in near the tracks but the train stopped only to drop a car or two when there was a harvest transport to be done. It's all kind of sad.


I really came to like Benjamin, and in a way to love the little town. It lies on the north-south highway south of Truscott and centers where the east-west highway makes a stop-light cross roads. Ten miles south is Knox City. Benjamin still holds on, although its population is getting top heavy in age. It even picked up a little in the late 1960s and early 1970s. It had a school, several filling stations, a few stores and business offices, the court house and Hazel's Cafe. The last time I went through town, Hazel's was closed, with a "For Sale" sign on the door. Its passing was not matched by an opening of a new place.

It was in 1957 that we set up camp on Driver's lease northwest of town, where Jack Kahn had found the bone layer. For some five years that was our spring or summer home as we dug in our quarry. It was a marvelous site on which a whole generation of my graduate students cut their paleontological teeth. We opened it again in 1971, but the charm had gone and the old suspicions of ranchers, once dispelled, had all come back. It was a dreary anticlimax.

The people of Benjamin, numbering about 350, tolerated those odd strangers who holed up in that godforsaken back country. Mickey Driver, of the ranch, had a good idea of what we were doing. For all of his tough ranch manners, he was actually well educated. He tried to hide it. His aging mother and father came out to see the quarry once in a while. Mr. Driver was much impressed by the big hole, but allowed as to how his land was mostly holes anyhow. Spritely Mrs. Driver, all of 5 feet tall and 90 pounds, just looked on knowingly. While ranching went on, she took off, flying to Paris to see the world.

When we hired a bulldozer in our second season word got around that something really was going on out there. One day at the Texaco station a big, handsome man of 25 or so approached me. Right off he said he was a coach and teacher, in that order, at the school and could he bring his class out to see our dig. I said that would be fine but he would have to clear it with the Drivers. They didn't like anyone running back and forth over the five miles to our camp unless they knew who it was. The road went across the land of three different ranchers and there were five gates to open and close.

About 25 youngsters came out. They had fun looking at the bones, chasing lizards, looking for snakes and teasing each other. The teacher told me it was the first time he had seen a glimmer of interest in their eyes! He had come to coach, which he loved. He ended up with a physics class, which he hated. His young, pretty wife was pregnant and the small town closed in pretty tight. He had been a top basketball player at Texas A and M and, as he put it, a basketball bum. He still played the circuit in summer. Next year he was gone.

Later a church group came out. Evolution was a very touchy subject and pretty much taboo. I tried not to offend, for beliefs are delicate. But this group, on a Sunday, nearly stumped me. The reverend asked me to tell them what we were doing, which I did. They seemed mildly interested although a bit upset when I said the materials were about 250 million years old.

"Was that before the flood?" one elderly gentleman asked.

"Well. . .,"1 hesitated, while my graduate students looked to see how their prof would get out of that one.

"Well," again, "it was during a flood that these bones got put down, but not Noah's flood, a long time before it."

"Before!" exhaled the man in disbelief, "What flood before?"

"The San Angelo Flood," interjected the reverend with the grace of his office.

"Oh," said the man, relieved. But then, "Was it before or after the light?"

"Had to be after. These animals are green plants and they needed light," I said, getting back on the track.

I suppose I might have launched into an explanation of years, how to date rocks, how animals and plants developed (evolved) and how one might reconcile the Bible with geological events. But beliefs are important, and the myths that support them are the materials of human rationalization of the disturbing and unfathomable. I don't feel they should be tramped on too hard.

Once they had found the way to camp, some of the youngsters from school began to come out on their own and Mr. Driver didn't like it. Also they really cut into our working time. So I had the principal announce in school that they were not to come. I hated to do this, but otherwise we would have been thrown off the Driver property. But as the years went by I saw many of the youngsters in town, where we had become fixtures, even storing our gear in the loft of the service station. Late one afternoon, a delegation of three of the boys arrived at our camp, saying they had asked Mr. Driver and it was all right. We talked and they hinted around that they had something on their minds. Finally one asked me if I would give the graduation talk at their eighth grade ceremony in a couple of weeks. I was mightly flattered and said yes, if it was all right with the principal. One of the boys was his son, trying hard to find a way into nuclear physics. I hope he made it. They carried my consent back over the 11 miles to town on their bicycles. I really couldn't refuse to talk — I was too moved by the invitation.

It was a fascinating ceremony. There were 13 boys and girls graduating, decked in their finest clothes and with caps. The gym was packed with 250 or more people, most of Benjamin. Prizes for the bests of the year were awarded. I had borrowed a coat from the principal, three sizes too large. First, to my amazement, I was given an award, for what I am not quite sure. A very pretty, blond teacher received her award as teacher of the year.

Then my "address." It lasted about 15 minutes and was more or less midwestern "corn." I ended up saying I might not be back too many times, but to remember that "big daddy from Chicago will be watching you and wishing you well." It seemed to go off well and when I dropped in to Hazel's a few years later, a gentleman come over to me.

"Ain't you the one who gave the talk at the school?" he asked. "That was a good one."

Ending the graduation was a talkfest outside of the school. The pretty teacher of the year came hurrying over to me. "You-all better change boxes with me before you go back out there," she said. "Take this one, it's got your shirt in it. The other's a frilly blouse for me. I don't think the boys would admire you in it."

We closed the quarry soon and opened it up just once more, as I said, after I had moved from the University of Chicago to UCLA. It wasn't the same. Benjamin was still there, but the young people and teachers were gone. The older youngsters were bussed to consolidated schools. For some years, I saw old friends as I dropped by the Texaco station in Benjamin and stopped to see Wade and Maude in Seymour. It was good to keep it alive, for there is so much to learn from these towns and their people that they must not just fade away. Who will teach humility to our young city people?

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