14S The American Gfeoipgisi. September, 1894 
cle on the Cretaceous rocks of Manitoba,* in which, referring 
to the Cretaceous of America in general, lie says that "this 
formation contains no beds of true chalk." At the meeting 
of the Association of American Geologists in April, 1841, Nic- 
ollet gave an account of the geology of the regions covered 
by his explorations along the Upper Mississippi and Missouri. 
In this account the Cretaceous strata along the Missouri are 
noticed, and the statement is made that no true chalk or Hint 
was observed. Lvell also encourages the notion that there is 
no chalk in America ; but it will not be necessary to make 
further quotations in illustration of the attitude referred to. 
While some of the leaders of geological thought on this side 
of the water have been slow to acknowledge the presence of 
chalk in the American Cretaceous, the plain people who are 
not geologists, not governed b} T conventionalities nor influ- 
enced b} r authorities, have never hesitated to call the material 
composing certain parts of the Niobrara deposits "chalk." At 
Saint Helena, Yankton, and wherever, indeed, the formation 
outcrops in massive la} r ers, the material is constantly referred 
to as "chalk," "chalk-rock, 1 ' or "chalk-stone." The use of one 
or another <>£ these terms in common speech is more than fifty 
years old. for in 1.S41 professor Bailey received from the far 
northwest a sample of what was locally known as "prairie 
chalk, "f 
What is ( halk ? 
Whether the material composing the Niobrara deposits is 
chalk or not may depend somewhat on our definition of the 
term: but if in England the name is applicable to a soft 
whitish calcareous rock that accumulated on a sea bottom 
lying beyond the reach of mechanical sediments, and was com- 
posed of multitudes of practically entire shells of Foramini- 
t'eia imbedded in an imperfectly indurated matrix of cocco- 
liths and comminuted foraminiferal debris, then the term 
may be justly applied to a very large portion of the deposits 
of the Niobrara age along the Missouri river. For. in the 
first place, a very casual examination of the material would 
*Noteou the occurrence of Foraminifera, Coccoliths, etc., in the Cre- 
taceous Hocks of Manitoba, Canadian Natutalist, vol. vu. No. •">. 1874. 
IAiimt. .lour. Sci. and Arts, h'rsi series, vol. xli, p. 100, 1841. 
