32 SMITHSONIAN INSTITUTION 



h3pothecated for the period of Hamilton deposition. The shore line, 

 it was admitted, was irregular and a narrow strait through which 

 there was supposed to be a mingling of the faunas of the eastern and 

 western arms of the immense sea was thought to have existed where 

 the state boundaries now define Wisconsin and Michigan. Dr. E. O. 

 Ulrich of the U. S. Geological Survey was the first to point out that 

 it was only in exceptional cases that such conditions prevailed, and 

 now, through the present detailed study, it is definitely known that the 

 actual conditions of deposition were quite different. It is still ques- 

 tionable as to just where the Wisconsin Devonian strata belong in 

 the general geological column ; but stratigraphic observations have 

 established the fact that the entire Michigan section lies below that 

 of Ontario' while the Ontario strata belong in a position below the 

 middle of the typical Hamilton series of New York State. 



Nearly two tons of selected specimens of beautifully preserved 

 and finely sculptured fossil shells and corals were shipped to the 

 Museum. These, together with the collections already in the Mu- 

 seum's possession, form as nearly a perfect series of fossils from 

 these beds as can be brought together. 



