No abstract

WITH AN INTRODUCTORY NOTE BY S. W. WILLISTON Recently, during a visit to Norman, Oklahoma, Professor Gould, director of the State Geological Survey, called my attention to a large fossil bone which had lately been discovered in the Trinity Cretaceous of that state by Mr. Pierce Larkin of the survey. This specimen, clearly a morosaurian coracoid, furnishes the first indisputable evidence of the occurrence of the sauropod dinosaurs in the Cretaceous of western America. At my suggestion Mr. Larkin has prepared the following brief description of the Trinity deposits of Oklahoma, giving the precise horizon of the fossil. The precise taxonomic location of the specimen is not possible, since generic characters are not well displayed in the coracoids of the dinosaurs, and because of the partial mutilation of the specimen as it occurred in its matrix. Excellent figures of the specimen, furnished by Professor Gould, will render unnecessary a detailed description of the bone. The occurrence of the Sauropoda in the Lower Cretaceous is of course to be expected, since the recent discovery of similar remains in the Upper Cretaceous of Africa. I have long believed that the Morrison beds of the west are, in part at least, equivalent in age to the Comanche Cretaceous of the interior.-S. W. WILLISTON. The Trinity division of the Cretaceous of Texas contains three distinct formations, the Travis Peak, the Glen Rose, and the Paluxy. The Travis Peak and Paluxy are sand members, while the Glen Rose is calcareous. Toward the north this formation loses its distinctive characteristics and merges gradually into the sandy members above and below until one part of the Trinity cannot be distinguished from another. Throughout northern Texas and Oklahoma there is practically no change which could be made use of in separating 93 This content downloaded from 044.224.250.