8 
PALAEONTOLOGY OP NEW-YORK. 
The shell is of more equal width throughout and more symmetrically oval, and 
also much larger than the L. sjpatulata of the Genesee slate. It is likewise more 
prominent along the centre of the upper half of the shell. One valve (the ventral ?) 
appears to have been more convex- than the other. 
Geological formations and locality. In the shales of the upper part of the 
Hamilton group, on the banks of Seneca lake. 
lingula ligea, var. 
PLATE II. 
The specimens from the lower part of the Portage group are larger 
than those from the Hamilton group, and have the sides somewhat 
straighter; while the cardinal extremity, is not so rounded, and slopes 
in nearly a right line on each side of the beak. The surfaces are not so 
well preserved as in those of the Hamilton group. This may ultimately 
prove to be a distinct species. 
Geological formation and locality. In the arenaceous shales of the Portage 
group : at the falls below Trumtmsburgh, New-York. 
lingula palaeformis. 
PLATE I. 
Lingula palceformis : Hail, Thirteenth Report of the Regents on the State Cabinet, p. 76. 
Shell broadly subovate; sides sloping in a nearly straight line from the 
beak to half the length of the shell, convex at the umbo and depressed 
below, the length a little greater than the greatest width, rapidly 
expanding for about two-thirds the length of the shell, below which 
it is abruptly rounded : shell thick. Surface marked by strong concen¬ 
tric lamellose striae, and, in the exfoliated surface, by fine radiating 
striae. 
This species, in general foTm, resembles the L. sjpatiosa of the Lower Helder- 
berg group, but differs conspicuously in the surface striae ; and among a conside¬ 
rable number of specimens, the dimensions are the same as the specimens figured, 
being nearly two-thirds the length of the Lower Helderberg species. 
Geological formation and locality. In the shales of the Hamilton group ; asso¬ 
ciated with numerous known fossils in a loose fragment of rock, found in the 
valley south of Cayuga lake. 
