MEMORIAL OF S. W. WILLISTON 71 



Kansas Academy of Science, the Kansas University Quarterly, and the 

 University Geological Survey of Kansas; also three volumes on the Cre- 

 taceous Fishes, in cooperation with Alban Stewart; and Paleontology 

 {Upper Cretaceous) , Part I, Volume IV, of the University Geological 

 Survey, which was chiefly prepa^red by Williston, with the assistance of 

 his students — Adams, Case, and McClung — -and is a thorough review of 

 the geology and marine fauna of the Cretaceous seas, containing the first 

 clear distinctions and restorations of the great Kansas mosasaurs — Cli- 

 dastes, Platecarpus, and Tylosaurus. This work became the standard for 

 all subsequent researches of Osborn, Wieland, and others on the Creta- 

 ceous fauna. It contains some admirable restorations of mosasaurs and 

 other fossils which may be compared with those of Dollo from the Maes- 

 trichtian of Belgium. The second part. Volume VI, of the University 

 Geological Survey, covering the Carboniferous and Cretaceous, published 

 in 1900, included the Cretaceous fishes, alluded to above, and the Carbon- 

 iferous invertebrates, by Joshua W. Beede. 



In 1897 Williston published his first paper on Paleozoic tetrapods — a 

 brief description of "A new Labyrinthodont from the Kansas Carbon- 

 iferous"; his second was on the "Coraco-Scapula of Eryops Cope,*' in 

 1899; but nearly a decade elapsed before the Paleozoic reptiles and am- 

 phibians became his chief subject. From 1897 to 1902 he was engaged 

 chiefly on his series of papers on fossil vertebrates of Kansas for the 

 University Geological Survey of Kansas. 



Williston concluded his studies of the Cretaceous fauna during the 

 early years of his professorship in Chicago, beginning in 1902. Thus his 

 work on the Kansas Cretaceous fauna, following the very disjointed con- 

 tributions of Leidy, Marsh, and Cope, based on inferior material, marks 

 the turning point in this field to the new order of description and gener- 

 alization based on complete material, including even the skin impressions 

 of several great mosasaurs. In his observations on the mosasaurs, plesio- 

 saurs, pterodactyls and marine turtles, and the birds with teeth, Odon- 

 tornithes, he placed the osteology of these several animals on a much more 

 secure basis, adding a number of new generic types, such as a short-necked 

 plesiosaur, Dolichorhynchops oshorni. 



His interpretation of function and habit is shown in his restorations of 

 all these types, and his first observations on the feeding habits of the 

 plesiosaurs and his more mature views on several of these animals were 

 published during his sojourn in the University of Chicago, namely, "Re- 

 lationships and habits of the mosasaurs," Journal of Geology, 1904; 

 "North American Plesiosaurs," 1903, 1906, 1907. His first contribution 

 to the phylogeny and classification of the Reptilia as a whole appeared in 



