760 THE PALEONTOLOGY OF MINNESOTA. 
[Communication 
COMMUNICATION. 
Professor N. H. WINCHELL, Slate Geologist. 
Srr:—At your request I have prepared the following chapter, embracing descriptions of the Cephalo- 
poda of the Lower Silurian rocks of Minnesota, which is herewith respectfully transmitted. 
I have the honor to remain, sir, 
Very truly yours, 
JOHN M. CLARKE. 
ALBANY, N. Y., September 10, 1894. 
