1847,| SHARPE ON THE PALZOZOIC ROCKS OF N. AMERICA. 147 
The works principally consulted were the following :— 
Annual Reports of the Geologists of the State of New York for 
1838, 1839 and 1840. 
Mr. Conrad on the Silurian and Devonian systems of the United 
States, with descriptions of new Organic Remains; in the 
Journal of the Academy of Natural Sciences of Philadelphia, 
vol. vill. p. 228, read 18th Jan. 1842. | 
Reports on the Geology of New York, viz. :— 
Mr. Mather on the Ist Geological District, 1842. 
Dr. Emmons ,, 2nd AS ay 1842. 
Dr. Vanuxem ,, 3rd a i 1842. 
Mr. J. Hall ,, 4th e a 1843. 
Dr. Dale Owen on the Geology of the Western States of North 
America ; Journ. of the Geol. Soc. of London, vol. ii. p. 433. 
Besides these, I have been favoured by Mr. Lyell with the use of 
a portion of an unpublished work by Mr. James Hall, on the Paleeon- 
tology of the State of New York, which that gentleman has for- 
warded to Mr. Lyell as the sheets passed through the press. This 
work is to contain figures and descriptions of all the species of fossils 
of New York, with many of those of the surrounding states; and it 
promises to form, when completed, a standard work on Paleontology 
of so high a character, that it will be equally essential to European 
and to American students. In the face of this forthcoming publi- 
cation of Mr. Hall’s, I have felt it would be both unnecessary and 
unbecoming in me to undertake the description of any new American 
species, and I have limited myself to the examination and classifica- 
tion of the species already described, merely adding the number of 
unnamed species in Mr. Lyell’s collection, to show the proportion 
of European species which it contains. 
Hitherto English writers have not been in the habit of consulting 
American works for the descriptions of fossil species, but it has 
now become necessary for them to do so. In the following lists 
several English species are given, which though unnamed here, have 
been described and named in America; and when Mr. Hall’s work 
is completed, the number of species in this position will undoubtedly 
be much increased *. 
There is little difference between the various tables of the Palzeo- 
zoic formations of New York published by the geologists just referred 
to; but they are far from being agreed as to the manner in which 
their formations are to be classed in comparison with ours. The 
* M. de Verneuil’s able paper on the parallelism of the palzozoic rocks of North 
America with those of Europe, which was read to the Geological Society of France 
on the 19th of April 1847, and printed in the Bulletin of that Society, t. iv. 
p-. 646, has not been referred to above, because my paper was finished and in the 
hands of the Secretary of our Society before that part of the Bulletin reached 
England; and the regulations of our Society do not permit me to make any 
alterations in the paper after sending it to the Society.—December 1, 1847, 
D. SHARPE. : 
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