VALLEY OF THE MISSISSIPPI. &fi 



Thomas Say considered as an unknown spacies of 

 baculite,* no other organic remains were noticed by 

 us in this vast deposition of argillaceous matter, which 

 often appeared near the bank of the river in black- 

 ened sterile hills and cliffs of from two to three hun- 

 dred feet elevation. It is highly probable that the 

 fossil crocodile skeleton, or proteasauriis, mention- 

 ed by Lewis and Clarke, was deposited in this argil- 

 laceous bed, although I once found, on the loftiest 

 summits of the gravel hills of White River of the 

 Missouri, several fragments of large fossil bones, 

 apparently vertebra, accompanied by some eburneous 

 process partly transformed into silex. 



The calcareous cliffs which border the Missouri, 

 not far from the creek of the Maha village, more 

 closely resembled chalk than any thing of the kind 

 which I have heretofore seen or heard of in North 

 America, but cannot by any means be identified with 

 the same formation in the south of England and in 

 France. We could not discover in it any organic 

 reliquiae, nor any vestiges of flint. It is, neverthe- 

 less, sufficiently white, meagre, and absorbent, when 

 moistened, and marks with facility. Connected ap- 

 parently with this anomalous formation of chalk, we 

 observed considerable beds of what appeared to be 

 stalactitial gypsum, but whether a more general de^ 



* Published in Silliman's Journal, vol. II. p. 41, under tfcfe 

 name of baculites compressa. 



D 



