2 DESCKIPTIOX OF A SKULL OF 



From the gravel and the sand have been taken the following fossils, determined by Profs. E. D. Cope and R. 



Ellswortli Call : 



Equuf. major DeKay. 



SphcBrium striatum Lam. 



Spharium sulcatum Lam. 



Fisidium abditum Haldeman. 



Anodonta, sp. 



Valvata iricarinata Say. 



Gammarus, sp. 



Beds lilie these are found at various places on the Western plains, but they have suffered greatly by erosion. 

 Their occurrence in McPherson county is at a point marking the crossing of a line of minimum erosion (the water- 

 shed) over another line of maximum development (the trough). 



A study of the region and the deposits, in mj opinion, shows that (1) previous to the deposition of the Pleisto- 

 cene, the country was traversed by drainage channels considerably deeper than at present ; (2) the time of the making 

 of the gravel and the sand was probably coincident with a period of increasing humidity ; (3) the gravel and the 

 volcanic dust were deposited in waters that did not cover the cretaceous ledges in the vicinity ; (4) floating ice was 

 present as an effective transporting agent, when the sand and gravel were being laid down. 



In the gravel, a small boulder was found containing fossils, which have been identified by Mr. E. O. L^lrich as 

 belonging to the Lower Carboniferous. Large boulders are common, consisting of a pure white aggregate of micro- 

 scopic crystals of carbonate of lime. , Specimens of this material have been examined by Mr. George P. Merrill, 

 who says he has seen similar material from the Cretaceous of Texas. Both of these occurrences point to a southern 

 extension of the water in which the deposits were made. 



Yours, most sincerely, J. A. Udden. 



AuGusTANA College, Rock Island, III., Dec. 10, 1890. 



The specimen has not the appearance of having been exposed to violence or to 

 the vicissitudes of long transportation previous to its discovery, its present defects 

 evidently being caused by careless handling afterwards. Prof. Udden had, therefore, 

 good reasons for his hopes that the balance of the skeleton might be found in the same 

 gravel pit. These hopes proved futile, notwithstanding his energetic labors, but he 

 was rewarded by recovering the only missing portion of the right zygoma, and also a 

 dorsal vertebra which may or may not have belonged to the same individual. 



The original discoverers of the skull, ignorant of its value, removed both the 

 canine molars, to keep them as curiosities, and, for the same purpose, broke oft' the 

 protruding ends of five of the other molars, leaving only the 2d in the left maxilla 

 and the 2d and 4th in the right. In this operation they also removed portions of the 

 alveolar walls of the 1st and 5th molars and of the palatine and pterygoid bones 

 (PI. III). The left canine molar was afterwards returned, though short of its pulp 

 end ; also, the inner half of the piece removed from the 3d right molar. The descend- 

 ing ramus of the left zygoma as well as the intermaxillary bones were not found. 



Prof. Joseph Leidy (in his Memoir of the EMinct Sloth Tribe of JSforth Amer- 

 ica, Smithsonian Contributions to Knowledge, Dec, 1853) described two skulls of 

 Megalonyx jeffersoni Harlan. One of them, originally belonging to Dr. D. D. Owen's 



