50 CHARLES S. PROSSER 
Thickness Total 
No. of Zone— Thickness— 
Feet Feet 
stone with a thickness of 6% feet and perhaps it 
it may reach 74 feet. A massive layer near the 
middle of this zone, according to Mr. Hartnagel, 
contains abundant specimens of Modiolopsis 
dubius Hall and Leperditia alta (Con.) Hall 
while Spirijer vanuxemi Hall is common. The 
base of this zone marks the bottom of the Man- 
lius limestone with a total thickness of 544+ 
feet in the above section. 
4 Soft seam of shaly, much-decomposed mate- 
rial about $-inch thick. This layer appears all 
along the exposure at the first fall and the second 
spring west of the ‘‘ladder.”’ The overlying 
layers are all regular, so that this one marks a 
change in deposition and, apparently, a forma- 
tional line of division. 
3° Dark, contorted, seamy limestone with ap- 1o+in. 4h 
pearance of gypsum rock which, on examination, 
Mr. Hartnagel reports to be a sandy limestone 
with some clayey material; but no gypsum. 
This zone has a variable thickness and is more or 
less irregular. 
2 Layer containing much pyrite and many 33 ft. 34 
seams of calcite, where pyrite is abundant, weath- 
ering to a dirty yellow color. The rock contains 
frequent cavities, is broken, or has irregular 
structure. 
Te “Hudson River” sandstone, thickly bedded 
and very quartzose at top, dark olive-gray color, 
with pyrite scattered through the rock in small 
crystals. 
3+ 
nie 
me 
5 
ay 
w 
In my former section the rocks corresponding to Nos. 2 and 3 of 
the above section were referred to the Waterlime (Rondout)? which 
was accepted by Professor Schuchert in his discussion of the same 
section.? Professor Harris, however, stated that at this locality 
“there are four or five feet of gypsiferous and pyritiferous shales, 
resembling in many ways the Salina beds beneath the Cobleskill 
t Kighteenth Ann. Rept. State Geol. (N. Y.], p. 54. 
2 Am. Geol., Vol. XXXI, 1903, p. 172. : 
