wti.liams] EQUIVALENCY AS INTERPRETED BY GEOLOGISTS. 121 
The sections, A to I, are arranged in order along a curved line ex- 
tending from Licking County, Ohio, northeastward toward James- 
town, N. Y. ; thence eastward to Ithaca; thence nearly east ward to 
Norwich; thence southeastward to the Delaware Water Gap near 
Stroudsburg, Pa. These sections are placed in approximately the 
relative distances apart which the natural sections occupy along such 
a line. Such a line theoretically represents a section at right angles 
across the successive zones of conditions of sea bottom out from a 
shore which had a general trend parallel to the present Atlantic 
coast and the general Appalachian axis. The total distance repre- 
sented is about 500 miles. 
The several sections are, for thickness and classification of forma- 
tions, based upon official survey reports, revised in some cases by 
special surveys; and the range of the fossil faunas has been deter- 
mined by special detailed investigations, accomplished chiefly by the 
persons named below, viz: 
A. Licking County, Ohio, revised by Orton, Herrick, and Prosser. 
B. Meadville, Crawford County. Pa. , and across Erie County, Pa. ; Second Penn- 
sylvania survey (I. C. White), Q4; revision by E. M. Kindle and H. S. Williams. 
C. Jamestown, Chautauqua County, N. Y., and Garland , Warren County, Pa.; 
Second Pennsylvania survey (Carll) 1 4, and G. D. Harris; range of faunas, E. M. 
Kindle. 
D. Warren, Warren County, Pa.; Second Pennsylvania survey (Carll) I 4, range 
of faunas, E. M. Kindle and H. S. Williams. 
E. Genesee Valley and Olean, N. Y. ; H. S. Williams; section revised by E. M. 
Kindle and M. L. Fuller. 
F. Ithaca and Cayuga Lake, N. Y.; H. S. Williams, E. M. Kindle, and H. F. 
Cleland. 
G. Chenango River Valley, New York; OS. Prosser and H. S. Williams. 
H. Catawissa, Columbia County, Pa. ; Second Pennsylvania survey (I. C. White) 
G 7; range revised by E. M. Kindle. 
I. Monroe and Pike counties, along Delaware River, Pennsylvania; Second 
Pennsylvania survey (I. C. White) G 6; range revised by C. S. Prosser. 
The range of the faunas is expressed by the cross lines marked 1 to 
5 and the letter R. 
The line marked 1 represents the upper Limit of range of the 
typical fauna of the Onondaga limestone. 
Line 2 is the upper limit of the pure I Iain ill on fauna/' 
Line 3 is the lower limit of the Chemung fauna. 
Line 4 is, for the western sections, the lower limit of the Waverly 
fauna; in the Ithaca section (F) and the sections farther east, il is 
the highest level at which definite I races of the Chemung fauna have 
been detected. 
Line 5 is the base of the Olean conglomerate (E) and of other con- 
glomerates regarded by stratigraphy's to be its equivalents. In the 
easternmost, section (1) it- is called Pottsville conglomerate series. 
"In section F this Line, by mistake, is drawn to cross the section al top instead of a1 bottom of 
the Tnlly limestone. 
