COPE ON GEOLOGY AND VERTEBRATE FOSSILS. . 569 



Sea/phites clieyennensis O., Battle Creek, Dakota. 



Inoceramus pertemiis M. & H., Judith River. 



Tcmcredia americana M. & H., northwest border and Oo^Y Island. 



Cardium speciosum M. & H., Cow Island. 



Cardium fiuhquadratum Ed, & Shnm., northwest border. 



Mactra formosa M. & H., Cow Island. 



Mactra alta M. & H., northwest border. 



Mactra warrenana M. & H., Battle Creek. 



Lunatia concinna M. & H., Battle Creek. 



Lucina oceidentalis Morton, northwest border. 



Tellina scitula M. & H., Battle Creek. 



Cnculhva slmmardii M, & H., Battle Creek. 



Piestochilns scarhornini M. & H., Battle Creek. 



Fi/ropsis hairdii M. & H., Battle Creek. 



In the Judith reo'iou, the relation of the Fox Hills sandstone to the 

 superincumbent strata is everywhere observable. I select as an ex- 

 ample a bluff' of some 800 feet elevation on the north side of the Mis- 

 souri, which is in proximity to the one represented in Fig*. 1. The 

 sandstone forms a ledge of 25 feet thickness, elevated say 50 feet above 

 the plain. Resting upon it is a thick bed of sandy aiid alkaline marl, 

 at the base of which, and so immediately above No. 5, I found the fol- 

 lowing Vertehrata: — 



BeptiUa. 



Crocodilia: — Proccelian vertebrne, and teeth with opposite cutting 

 carinfe. 



Saiiropterygia: — Fragments of vertebrsB. 

 Pythonomorpha: — Fragments of vertebrae. 

 Testudinata: — Fragments of Trionyx and an Emydoid. 



Pisces. 



Isospondyli: — Ischyrhiza teeth ; JEnchodus teeth and jaws. 



HoIocephali:-^Gh\mpero\c\ jaw. 



Elasmohrancliii: — Otodiis sp.; Lamna sp. 

 In all ten species, which are mostly of. characteristically Cretaceous 

 type. Mingled with them were fragments of large bones much resem- 

 bling those of Dinosauria, but not characteristic. This light-colored bed 

 has a depth of from 100 to 115 feet, and is sometimes divided by a thin 

 layer of sandstone 15 feet from the base. The upper portion of the 

 stratum is more arenaceous; the lower more argillaceous and alkaline. 

 The whole is capped by a thin l)ed of sandstone, which varies from straw- 

 colored to rusty in color and from 3 to 8 feet in thickness. In and im- 

 mediately below this stratum occur the bones of Dinosauria. From this 

 point upward, we have undoubted deposits of the Judith River epoch, 

 or Cretaceous No. 6, which, near the Judith River, attain a thickness 

 of from 100 to 500 feet. The bed which rests on the sandstone just 



