THE UNCONFORMITY AT THE BASE OF THE 
ONONDAGA LIMESTONE IN NEW YORK AND 
ITS EQUIVALENT WEST OF BUFFALO™ 
EDWARD M. KINDLE 
INTRODUCTION 
The importance of stratigraphic breaks has recently been 
emphasized by a geologist in the following words: “The discovery 
of such breaks, whether previously suggested by faunal evidence 
or not, is the most important duty of the progressive stratigrapher.”” 
If the demonstration of these breaks is included as a part of the 
duty of the stratigrapher, most geologists will heartily agree with 
this sentiment. Stratigraphic breaks not fully supported by 
evidence have much the same status in geology as have new species 
which have been discovered but not figured or described. They 
may or may not be genuine, but in either case they are outside 
the pale of science until their sponsor has submitted valid evidence 
of their existence. 
The present paper is intended as a contribution to the demon- 
stration and synthetic discussion of a particular unconformity. 
A stratigraphic break with so great a lateral extent as the one 
separating the Onondaga and pre-Onondaga sediments merits a 
more detailed description than it has yet received. The discon- 
formity? at the base of the Onondaga limestone, although previously 
known in western New York‘ and Ontario,5 has not hitherto been 
1 Published with the permission of the Director of the U.S. Geological Survey 
and the Director of the Canadian Geological Survey. 
2 Bull. Geol. Soc. Am., XXII (1911), 541. 
3 The term disconformity will be used in the sense proposed by Dr. Grabau 
(Science, N.S., X XIX [10905]) where it is applicable in this paper; but it passes, as 
will be shown, into a clino-unconformity (Crosby, Jour. Geol., XX [1912], 296) in 
its western phase. The broader term unconformity is used to include both types of 
stratigraphic break. 
4J. M. Clarke, Memoirs New York State Mus., No. 3 (1900), pp. 96-98; A. W. 
Grabau, Bull. New York State Mus., No. 45 (1901), pp. 117-20. 
5C. R. Stauffer, Bull. Geol. Soc. Am., (1912), pp- 373-75- 
301 
