354 
PALAEONTOLOGY OF NEW YORK. 
CYRTOCERAS, Goldfuss. 1832. 
A glance at the following historical sketch will show the proportion of the 
species which have already undergone changes in generic reference, and the 
inclusion of forms in the genus Cyrtoceras possessing the most unlike charac¬ 
ters. This has arisen from the recognition of genera which have as yet no 
recognized defined limits beyond the individual opinions of the various authors. 
Another source of constant confusion is the poverty of the material, which, so 
long as it continues, must render a satisfactory determination amd arrangement 
of all the species impossible. 
One cause for the uncertain and unsatisfactory reference of species, in this 
country, during former years, has been the want of books for reference, and of 
collections for comparison. Every author has been compelled to rely upon 
such information as lay within his reach; and this was often of the most 
incomplete and fragmentary character. There existed, also, a preconceived 
opinion, from earlier teachings, that the genus Nautilus did not exist in Palae¬ 
ozoic formations; and owing to this impression, such forms as Cyrtoceras 
maximus, Conrad, and Gyroceras Burlingtonensis, Owen, were referred to these 
genera, while they have all the characteristics of genuine Nautilus, to which 
they are now referred. From a similar misapprehension, or preconceived 
opinion, the generic term Lituites has been applied to forms not very dissimilar 
from those just named, and which have all the features of true Nautilus; 
while others, arranged under the same generic term, belong to the genus 
Gyroceras, as generally accepted. 
The species here described, and indicated below, are placed provisionally 
and with some degree of reservation under this genus. At the present time, 
and with the information at hand, no satisfactory generic separation can be 
made. In the following arrangement, those species preceding C. eugenium, 
viz., C. metula , C. formosum, C. densum, C. Hector , C. liratum, C. alternatim and C. 
morsum, form a heterogeneous group without natural interrelations, and with¬ 
out any special connection with the species following. 
