412 



G. R. Wieland — Archelon ischyros. 



natural position. All this could be due of course to scavengers, 

 but I am strengthened in the opinion that it was owing to cur- 

 rents from the fact that across the Miocene Butte not more 

 than a half mile awaj, on verj much the same horizon, there 

 were several very distinct gravel strata, the gravel ranging in 

 size from one to three inches in diameter. 



The vertical section above the position of the fossil was 

 approximately as follows : 



Miocene { 



Cretaceous < 



" Buttes" with a thickness of from 75 to 100 feet. 

 Flat topped ("railroad buttes," as locally termed 

 because of their embankment-like appearance) 

 owing to a hard flinty to opalaceous layer which 

 caps them. Mostly hard grayish white clays 

 and marls, weathering into red bowlders contain- 

 ing frequent remains of Testudo, especially 

 about 30 feet from the summit. 



Gravelly clays with large flow-and-plunge struc- 

 ture only to be noted in the most favorable 

 positions among the expanse of weathering hills ; 

 in most places appearing as a plain gravelly 

 layer one or two teet thick, although the actua 

 thickness is fifteen feet. 



Light red or yellow marly clays containing Inocer- 

 amus^ and very rarely Baculites, with frequent 

 masses of septaria, 30 ft. 



Deep red to black *' gumbo," 5 ft. 



Thin band of yellow marly clay, 5 in. 



Deep red to black marl or " gumbo," 5 ft. 



Underneath the plastron were found four or five species of 

 MoUusca poorly preserved. There were also found in good 

 preservation scales of a fish allied to Beryx^ also of an unre- 

 f erred Malacojpterygian^ and a shark's tooth — a very broad- 

 toothed Lamna:^ 



* As a matter of convenience these two references are added : A. S "Woodward, 

 On Leathery Turtles Recent and Fossil, Proceedings Geologist's Association, vol. 

 X. Also, Die Chelonier der Norddeutschen Tertiarformation (contains a description 

 of Pseudosphargis ingens von Konen) von W. Dames, Palaeontologische Abhand- 

 lung, Jena, 1894. 



