WAGNER: TURTLE REMAINS FROM THE FT. PIERRE. 203 
several examples, is certainly worthy of note, and throws doubt 
upon the propriety of the terms Colorado and Montana in Cretaceous 
stratigraphy. That the formation whence the specimen came is 
Ft. Pierre is evident from the invertebrate fauna. Prof. Williston 
also informs me that the genus P/atecarpus, and possibly the 
species corypheus, occur in the same horizon. Furthermore 
Prof. Case considers* Mr. Wieland’s Archelon ischyros,+ from the 
Ft. Pierre of South Dakota, congeneric, if not conspecific, with 
the Protostega of the Niobrara. 
Prof. S. W. Williston has furnished me with the above speci- 
mens, as well as with constant aid and encouragement in this and 
other work. To him my deepest gratitude is due. 
*Journal of Morphology, Vol. 14, P. 52, (1897). 
+Am. Jour. Se. Vol. II, Dec., 1896. P. 399, 1 Plate. 
