916 
PALAEONTOLOGY OF NEW-YORK. 
tive form in that epoch. The species has a wide geographical range, being known 
throughout New-York, Canada West, Ohio, in the Mississippi valley, and as far 
south as Virginia. 
The 8. fimbriata is the first of this type in our formations, but is represented 
by similar forms* to the close of the Carboniferous period. 
In the illustrations of these species, the fragment 1 is from the Oriskany sandstone 
the figures 2, 3 and 4 are from the Schoharie grit; figures 5-11 are from the 
Corniferous limestone : the remaining figures are from the Hamilton group. 
Geological formation and locality. This species occurs in the Oriskany sand¬ 
stone at Saugerties in Ulster county, and at Knox in Albany county, and probably 
in Schoharie. It is found in the Schoharie grit in Albany and Schoharie counties, 
and in the Corniferous limestone in the same region ; and at Cherry-valley ; 
Westmoreland, Oneida county ; Onondaga-hollow, Onondaga county ; Stafford, 
Genesee county ; Williamsville, Clarance, and other places in Erie county ; in 
Canada West, and at Columbus and other places in Ohio. 
In the Hamilton group, it occurs on the shores of Seneca and Cayuga lakes, 
and upon Canandaigua lake ; at York and Moscow in the Genesee valley ; and at 
Darien; at Eighteen-mile creek, and other places in Erie county. Also in the same 
group in Maryland and Virginia ; and at Davenport and New-Buffalo, Iowa ; at 
Hock-island, Illinois ; and elsewhere in the Mississippi valley. 
Spirifera mucronata. 
PLATE XXXIV. 
Delthyris mucronata : Conrad, Ann. Report on the Geology of New-York. 
“ “ Vanuxem, Geol. Report Third District, p. 150. 1842. 
“ “ Hall, Geol. Report Fourth District, p. 198. 1843. 
Spirifera mucronata : Billings, Canadian Journal, May, 1861. 
Shell more or less gibbous, semicircular, semioval, or triangular in out¬ 
line ; cardinal angles sometimes truncate but usually extended, and 
often extremely prolonged into mucronate points, giving a length of 
binge-line two, three or four times as great as the shell; sides straight 
or curving, the front straight or concave. 
Ventral valve often scarcely more convex than the dorsal, but in very 
gibbous forms becoming more unequal, gently curving to the lateral 
margins. The beak is small, and incurved over the narrow linear area, 
the mesial sinus is sharply defined quite to the apex, and limited by 
angular plications which are Stronger than the adjacent ones. The 
* S. pseudolineata and S. setigcra. see Geology of Iowa, pp. 645 and 705. 
