Manlius Formation of Nezv York. — Schuchert. 171 
THE BERTIE FORMATION OF CHAPMAN. 
Clarke and Schuchert* in proposing the term Rondout, in- 
tended to apply this name to the "Waterlime" formation char- 
acterized by an abundance of Eurypterus. It now turns out 
that the formation at the type locality, .Rondout, N. Y., is 
younger and lies above the Cobleskill member of the Manlius 
and it has therefore lost its intended significance (see Rondout 
section). For the lower Waterlimes so characteristic about 
Litchfield and situated beneath the Cobleskill zone of the Man- 
lius, and again the same formation about Buffalo, New York, 
beneath the "Bullhead rock" and above the Salina, it is pro- 
posed to use hereafter the name Bertie formation, proposed 
by Chapman in 1864. 
In giving the distribution of the "Lower Helderberg 
group" in Canada, Chapmanf defines the Bertie formation as 
follows : 
The Lower Helderberg group "thins out towards the west, 
and presents merely two or three outlying patches in the 
neighbourhood of ^lontreal [= Becraft], and a comparatively 
narrow strip of slight thickness in Western Canada, between 
the eastern end of Lake Erie and the township of Cayuga. 
* * * This strip, in no place exceeding fifty feet in thickness, 
consists of the lowest division of the group as subdivided by 
the New York geologists, or of the equivalents'of their 'Water- 
lime group.' With us, in Western Canada, it might be called 
the 'Bertie or Cayuga dolomite,' as its only known exposures 
are in those townships ; or a still better term would be the Eu- 
rypterus formation, so named from its principal and character- 
istic fossil. * * * In the above townships its strata consist 
of thin-bedded greyish dolomites, interstratified towards the 
base with a few brownish shales, and with a brecciated bed 
composed chiefly of dolomite fragments." 
• Bertie, Ontario, is but five or six miles west of Buffalo, 
New York, and the water-lime of the former place is the 
direct continuation of the last named region. It is therefore 
certain that Chapman gave the name Bertie formation to the 
Waterlime beds of western New York characterized by an 
abundance of Eurypterus. This formation about Buffalo is 
• Science. Dec, 1899. pp. 874-878. 
t A pooular and practical exposition of the Minerals and Geology of 
■Canada. By E.J. Chapman, Toronto, 1864-, p. 190. 
