The Utica Terrane in Canada. 167 
prepared showing the distribution of species known to date 
from localities where the Utica occurs in Canada, together 
with comparative lists of species from the same formation 
in the United States. 
H. M. A. 
Orrawa, March 28th, 1892. 
THe Utica TERRANE IN CANADA. 
Historical Sketch—Through the writings of Green, 
Orton, Rogers, Eaton, Mather, Conrad, Emmons, Hall, 
Whitfield, Walcott and others in the United States, together 
with those of Sir William Logan, Billings, Murray, Hunt, 
Dawson, Chapman, Laflamme, Nicholson and Smith in 
Canada, the Utica terrane has been fairly well established 
and defined as marking a distinct horizon or period in the 
series of strata constituting the Cambro-Silurian or Ordo- 
vician Epoch in North America. 
Whether it is viewed from a paleontological, strati- 
graphical or lithological standpoint, the Utica characterizes 
an epoch in the evolution of this continent which may be 
readily recognized over wide areas. 
First described by New York geologists from exposures 
of that formation near the town of Utica, N.Y., the Utica 
was defined as a “black and tender rock which reposes 
upon the Trenton limestone.” By some of the early 
writers it was spoken of as consisting of shaly strata whose 
total thickness exceeded nine hundred feet, whilst by others 
the very humble, yet perhaps truer estimate, was given of 
‘“ about seventy-five feet in thickness.’’ 
Stratigraphical characters and relations.—Inasmuch as the 
Trenton limestone is one of the most extensively developed 
and easily recognized terranes or horizons in America, and 
inasmuch as the Utica reposes directly upon it without any 
discordance of stratification whatever, the position of the 
Utica is therefore likewise easily known and ascertained. 
Wherever the sequence of Ordovician strata is unbroken, 
either by faults, foldings or denudation, from the Potsdam 
to the Hudson River, the presence of the Utica has been 
