274 Annals of the Carnegie Museum. 



by freshets. There is evidence of the existence of a current which 

 flowed from west to east. Mussel-shells and remains of tortoises 

 prove the fluviatile origin of the beds. 



In the lowermost of the strata which have been investigated we 

 have succeeded in finding skeletons, more or less complete, of nearly 

 a score of dinosaurs, large and small. One of the largest of these 

 skeletons, representing an animal provisionally referred to Bronto- 

 saurtis, or Apatosaurus, has been already taken from the matrix and 

 the skeleton is being installed in the Carnegie Museum. This is prob- 

 ably one of the most perfect skeletons of a sauropod dinosaur which 

 has ever been recovered. All the vertebra? from the axis to very near 

 the end of the tail were found in place; the whole of the pelvis, the 

 right hind limb, the two scapulae, all of the ribs, and the entire right 

 ^ore limb with the manus, as well as most of the left fore limb, were 

 discovered in such a position as to leave no doubt whatever that we 

 are dealing in the case of these remains with one individual. Num- 

 erous sternal ribs were also found. With this skeleton, lying about 

 twelve feet from the atlas, and in the same layer, was a skull the 

 condyle of which shows perfect adaptation to the atlas. Had nothing 

 in the past been written in reference to the structure of the skull of 

 Brontosanriis the conclusion would naturally and almost inevitably 

 have been reached that this skull belongs to the skeleton the re- 

 mainder of which has been recovered. The skull is decidedly like 

 that of Diplodocus, though very much larger in size than any skull 

 representing that genus of which the writer has knowledge. It is 

 characterized by the same feeble dentition. The fact that in this 

 particular layer, exposed to view in the quarry, there are also the 

 remains of one or two comparatively small animals, which may be 

 referred to Diplodocus, naturally suggests that the skull in question 

 might possibly have belonged, in spite of its apparent relationship to 

 the specimen of which I have spoken, to one of these other skeletons. 

 The curious fact, however, should here be mentioned, that in this 

 particular stratum, which thus far has only yielded one or two skele- 

 tons which are referable to the DiplodocidcB (in the accepted meaning 

 of that term), we have recovered the remains of at least eleven skulls, 

 all of which are characterized by the same general style of dentition, 

 although the skeletons, exclusive of the two which we can refer 

 without much doubt to Diplodocus, undoubtedly belonged either to 

 animals much more closely related to Brontosaurus, or some of them 



