Robert H. Denison 



1911-1985 



Xvobert H. Denison, former curator of Fossil Fishes at 

 Field Museum, died after a long illness in September 

 1985. He was a first rate scientist, a paleoichthyologist 

 (specialist in fossil fishes) of international stature. 



Born in Somerville, Massachusetts, on Nov. 9, 

 1911, he graduated from Harvard College with an A.B. 

 in 1933. From there he went to Columbia University, 

 where he also became well acquainted with the staff of 

 the American Museum of Natural History. Bob com- 

 pleted his studies at Columbia with a M. A. in 1934 and a 

 Ph.D. in 1938. A student of the world-renowned com- 

 parative zoologist William K. Gregory, Bob started his 

 career interested in fossil mammals. His Ph.D. thesis on 

 the broad-skulled Pseudocreodi (a primitive mammalian 

 carnivore) was awarded an A. Cressy Morrison Prize in 

 Natural Science in 1937 by the New York Academy of 

 Science. In the early 30s he joined Harvard field parties 

 to collect fossil mammals in Wyoming, Nebraska, and 

 South Dakota, and in 1947-48 he took part in a Univer- 

 sity of California expedition to Egypt and Kenya. 



In 1937 Denison became a member of the faculty at 

 Dartmouth College and assistant curator of the Patten 

 collection (now at the American Museum), which con- 

 tained Late Devonian (350 million years before present) 

 and Late Silurian (400 MYBP) vertebrates from Quebec 

 and the Isle of Oesel in the Baltic Sea. William Patten 

 (formerly professor at Dartmouth) had collected this 

 material to support his ideas about the origin of the chor- 

 dates from arthropods. This large resource channeled 

 Bob's paleontological interests in the direction of the 

 early vertebrates and resulted in a series of careful de- 

 scriptions of agnathans (jawless fish) and placoderms (a 

 large extinct group of armored fish). 



In 1948 he joined the Field Museum as curator of 

 Fossil Fishes, and began to build a collection of North 

 American Devonian and Silurian fishes. Besides the 

 anatomy, classification, and evolutionary history of the 

 early vertebrates, Denison was deeply interested in the 

 ecology of the earliest groups and the origin and early 

 history of their calcified skeletons. The prevailing and 

 widely accepted theory at the time held that the earliest 

 vertebrates were freshwater inhabitants and that some of 

 them later invaded the sea. Denison had visited and col- 

 lected in most of the North American localities of early 

 vertebrates and found that he could not agree with this 

 view. As the recipient of a Guggenheim Fellowship 

 (1953-54), he also visited localities in England, Scot- 

 land, Norway, and Sweden, and in the process dis- 

 covered evidence against the freshwater origin theory. 

 In 1956 he published a detailed review of the evidence 



regarding the habitat of the earliest vertebrates and con- 

 cluded that they inhabited marine, rather than fresh 

 waters. 



When Bob joined the staff, Field Museum had 

 virtually no fossil fish collection; by the time he retired, 

 at the end of 1970, the institution had one of the most 

 important and best curated collections of Devonian and 

 Silurian fishes in the world. Much of what Bob col- 

 lected, he also studied, and the results are published in a 

 series of major, technical accounts. 



In 1963, he discovered the earliest North Amer- 

 ican lungfish in the Lower Devonian of Cottonwood 

 Canyon, Bighorn Mountains, Wyoming. It still is the 

 only complete Lower Devonian lungfish known. This is 

 the only fish group that led him out of the Devonian 

 (345-395 MYBP) into the mid-Pennsylvanian (295 

 MYBP) of Illinois, and the study of tooth histology of 

 younger lungfishes. His specialty, however, was working 

 with agnathans and placoderms; his last two studies on 

 placoderms appeared in 1984 and 1985. 



For the well-known series, Handbook of Paleo- 

 ichthyology, he gathered extensive knowledge on the 

 placoderms (1978) and the acanthodians (1979). These 

 two volumes of the series are used extensively by paleo- 

 ichthyologists around the world. 



Denison was a Fellow of the Geological Society of 

 America and a member of the American Society of Ver- 

 tebrate Zoologists. He was an honorary member of the 

 Society of Vertebrate Paleontology, serving as its 

 secretary- treasurer from 1959 to 1961, and as president 

 in 1961 and 1962. 



Bob Denison was a quiet, well-liked and much re- 

 spected colleague, devoted to his scientific and curato- 

 rial responsibilities. He personified all the best character 

 traits of the New Englander he was: love for privacy and 

 independence, conscientiousness and sustained effort in 

 his work habits, strong need for orderliness, wry sense of 

 humor, valuation of substance over imagery and absolute 

 honesty. 



Following retirement, Bob and Mary Denison 

 moved to Lincoln, Massachusetts, where Bob became 

 a research associate at the Museum of Comparative 

 Zoology, Harvard University, and continued his 

 scientific work. 



Bob is survived by his wife Mary, three sons, John 

 H. Denison, David O. Denison, and Robert Wells, and 

 a sister, Mrs. Merdecai-Fischerman. 



—Rainer Zangerl, Curator Emeritus, Department of Geology, 

 and William D. Turnbull, Curator, Department of Geology 



