(Ringueberg on the Niagara Shales. 267 
following, provided the conditions favorable to the continuation 
and multiplication of organic life be maintained; and this ex- 
pectation is well sustained by the palaeontological wealth of the 
succeeding period. 
The Niagara shales. These shales were ushered in with a 
great profusion of life of many species. At the very threshold 
of the series we find represented with few exceptions the major- 
ity of the species to be found throughout their entire extent. 
From the beginning to the end there was gradual decadence 
in the abundance of life, and the number of species, till at last 
a few fucoids only remained. 
These notes on the shales refer strictly to their appearance 
within the confines of Niagara county. Here, at Lockport, they 
have a thickness of some seventy feet and can, upon palaeon- 
tological evidence, be divided into three parts which will be called 
thirds., although that designation will imply merely divisions 
defined by the comparative abundance and range of the fossils. 
The first or lower third comprises only some seventeen feet 
on the Erie canal — the only place where its measurement has 
as yet been effected. The rest of the series is divided into two 
parts of some thirty feet each, without any distinct line of de- 
marcation yet noted. 
The most conspicuous peculiarity of these three divisions is a 
regular upward decrease of the fossils. The lower third is 
highly fossiliferous with comparatively few thin bands of un- 
productive shale, chiefly in its upper part. In the middle third 
a diminution may be noted, the fossils being for the most part con- 
fined to bands of shale and some thin impure semi-calcareous 
layers ; or to isolated areas or patches. These bands are sepa- 
rated by various thicknesses of shale mostly, but not wholly, 
non-productive, the fossils growing scarce towards its upper por- 
tion. The upper third has a considerable quantity of fossils 
distributed through it, but they are few when it is compared 
with the rest of the shale, and are for the most part confined to 
their well separated layers. Taking these three divisions in or- 
der we will describe first in detail the lower third. 
This extends from the Niagara Transition bed or where that 
is absent, from the Clinton, to a layer which is well defined 
paheontologically, and which we will designate as the HornO' 
