In Memoriam; Chairman, Division of Geology, 1947-1950.
In 1950, Dr. Chester Stock, Professor of Paleontology and Chairman of the division, passed away. He was 58.
From the time of his coming to the Institute in 1926, shortly after the geological division was organized, Dr. Stock prosecuted a very vigorous program of research in vertebrate paleontology. He was interested mainly in the mammalian fossil remains secured from the Tertiary formations of the United States, west of the Rocky Mountains and in the northern part of Mexico.
There were several aims of this research. One was to determine from the collections of bones and teeth made in a large number of Tertiary sandstone and shale formations of diverse ages what kinds of animals roamed over the mountains and plains of western America in the successive epochs of the 60 million-years-long Tertiary period. These creatures were very different from the mammals now living in these regions; virtually all the species are extinct, and some whole lineages, such as the oreodonts, disappeared millions of years before Man appeared on this continent or had even originated.
A second purpose of vertebrate paleontology is to determine accurately the geologic age of the formation containing the fossils; because of their rapid evolutionary change, mammalian remains are especially serviceable.
Another aim is to infer from the types of mammals found in a formation something of the topography and climate of the country in the geologic epoch when they lived. Further, by assembling the fossil skeletal parts of successive species in the same lineage, such as horses or camels, it is possible to discern the evolutionary development and changes from creatures small and primitive to later or living species, usually much larger and more complex in skeletal structure.
Finally, from the structural changes in the animals and the contemporaneous alterations in topography, climate, and food supply, it is possible to derive some clues to the causes of evolution. Along the line of each of these aims in paleontology, Dr. Stock contributed (in an important way) through his writings and his teaching.
To secure the fossil material, Dr. Stock, with the aid of the late Eustace L. Furlong, Curator, and of William J. P. Otto, Sculptor and Preparator, and students and other assistants, organized many successful collecting expeditions to a large number of fruitful sites and areas in the West. The excellent collections he amassed and cataloged at the Institute for study and comparison purposes compare favorably with those in much older institutions. Age determinations of formations, which Dr. Stock was able to make with these materials, have been of very great value to petroleum and other geologists.
Dr. Stock's published contributions to paleontology were both numerous and important. He was the author of some 170 papers, ranging from short descriptions of individual new species of Cenozoic mammals 01 brief popular articles to voluminous monographs treating whole groups of species or genera of one family or all the various mammals found at one locality, each of these studies representing months or years of intensive research.
One such group, the peculiar heavy and herbivorous but clawed ground sloths, like the horses and camels only recently extinct in North America, claimed Dr. Stock's interest early in his scientific career and were treated in very important publications. He was the outstanding authority on this group for more than thirty years.
Another group to the evolutionary history of which Dr. Stock contributed in a very important way is the horse family, remains of which he collected and studied in forms ranging from the little five-toed Eohippus to the virtually modern horse. His published papers, prepared with great care and fully and effectively illustrated with drawings by the late John L. Ridgway and by David P. Willoughby, were outstanding examples of scientific accuracy and literary form.
His enthusiasm for and arduous application to research in vertebrate paleontology stimulated numerous graduate students to investigational work in that and closely related geologic fields. Striking skeletal mounts and complete restorations of extinct species of mammals and reptiles prepared under his direction are among the most interesting exhibits of scientific materials open to the public at the Institute.
Dr. Stock received his training between 1910 and 1917, and much inspiration, from the late Dr. John C. Merriarn, then Professor of Paleontology at the University of California at Berkeley. Under John C. Merriam, Dr. Stock early developed a deep interest in the remarkable and world-famous fauna of Rancho la Brea, now Hancock Park, and beginning in 1913, he published a long series of papers describing different groups of animals entombed there in the tar. Stock was very active in guiding the planning of a museum and other exhibits illustrating the fossil-recorded life at this fascinating paleontological site.
Initiated by the study of Rancho la Brea collections at that institution, Dr. Stock participated in the scientific activities of the Los Angeles Museum of History, Science, and Art to an increasing degree for more than three decades and was responsible for the magnificent restorations of prehistoric animal life for the West being exhibited there. He was Chief Curator of Science at the museum from 1948 to 1950.
Many honors came to Dr. Stock. He was elected a member of the American Philosophical Society, the National Academy of Sciences, the Geological Society of America, the Paleontological Society of America, the American Society of Naturalists, the American Society of Mammalogists, the American Association of Petroleum Geologists, and several others.