288 
[Assembly 
unless more time were allowed for explorations in the unsettled portions 
of this district. 
In company with my colleagucj Mr. Vanuxem, I passed several 
weeks in examinations along the boundary line between the Third and 
Fourth Districts. The admirable facilities afforded by the banks of Cay- 
uga lake, the valleys south and the ravines north, have enabled us satis- 
factorily to determine the succession and character of the rocks from 
Lake Ontario to the Pennsylvania line. Hereafter we shall be enabled 
to avoid collision and discrepancy in our descriptions, and to designate 
groups without confounding them with each other. We have also found 
the solution of many difficulties, in part arising from previous partial 
examinations, and also from the fact that the character of several rocks 
below the Onondaga limestone entirely or materially change in their 
eastern prolongation; and more especially after passing the longitude of 
Cayuga lake. 
In Wayne county, on either side of the outlets of Cayuga and Seneca 
lakes, the rocks are frequently covered with high alluvial hills, thus al- 
most precluding accurate examination; and in some of the softer rocks, 
which have been worn down by the same alluvial action, the conceal- 
ment is so complete as to leave us in entire ignorance of the underlying 
strata. In the neighborhood of the Canandaigua outlet the country is 
covered in the same manner; and the rocks are visible only where 
streams of recent origin have found a passage. Thus the examination 
of such regions is rendered laborious, and accuracy can be attained only 
by minute and multiplied observations, by continued investigation and 
an extended knowledge of different localities. 
With regard to the arrangement and succession of rocks presented in 
the section accompanying the report of last year, I have no important 
alterations to suggest. The names applied to the rocks were nearly all 
those which had before been used, or such as were merely descriptive, 
and intended to remain only till further research and concert of action 
should establish a nomenclature. This to some ext;ent has already been 
done; and thus far w^e will point out the changes to be made, and the 
names to be permanently applied. 
Every one who has studied rocks even partially, is aware of the in- 
sufficiency of mineral or lithological characters for giving nomenclature, 
and the many errors into which he may be led, whether in his own re- 
searches or by the mistakes of others. So likewise in the present state 
of our knowledge, we are unable in all cases to give names from fossil 
