SECOND ANNUAL REPORT 
Of T. A. Conrad, on the Palaeontological Depart 
ment of the Survey. 
The classification of the organic remains of New-York is approach- 
ing to a state sufficiently complete for an accurate grouping of the va- 
rious strata. In Europe, the equivalents of the New- York formations 
are divided into two great systems, termed Cambrian and Silurian, which 
are unconformable to each other. The organic remains do not greatly 
differ in each, but they are far more rare and limited in number of spe- 
cies in the older, or Cambrian system (in this country,) except in the 
two overlying rocks, or the lowest of the Silurian system. Still in the 
fossils of the older division, we can recognize a character sufficiently 
marked and distinct, to enable us readily to classify the strata wherever 
we may find them in the most distant localities. The upper term of 
the Cambrian system may be recognized in the vertical and contorted 
slates and olive sandstones of the Hudson river, extending from New- 
burgh to Glen's Falls. 
Organic remains, other than obscure Fucoids, are very rare, except in 
particular localities, where Fucoides serra, of Brongniart, abounds, and 
is very characteristic from its numbers, for in the Silurian rocks it is al- 
most unknown. Several other species of the genus to which the serra 
belongs, have also been found in the same localities. The F. dentatus 
Brong. also occurs, but is not nearly so numerous as in the Silurian 
slates. This species has been referred to Graptolites Linn, and is sup- 
posed to bear no analogy to marine plants; indeed, all the members of 
the group are very unlike the true fucoids of the Transition. These 
are nearly all the organic remains which occur in the slates, but frag- 
ments of the trilobite, Cryptolithus tersellatus have been very rarely 
found, a species common in the Trenton limestone at Fonda, on the 
Mohawk, and at Glen's Falls. Over the highly inclixied strata of the 
[Assem. No. 276. J 8 
