48 
No. 
12. 
If. 
CHARLES S. PROSSER 
Gypidula galeata (Dal.) H. and C., the charac- 
teristic fossil of the Coeymans limestone, was 
not noted until just above this zone. In this 
cliff it is evident that the line of division between 
the Manlius and Coeymans limestones is not 
sharply marked. The most clearly marked 
physical change is at the above-noted bedding 
plane, where Mr. Hartnagel prefers to draw the 
line of division between these two formations 
which, in some respects, appears to be the most 
satisfactory line of division. In the Indian 
Ladder highway cut from this bedding plane 
36+ feet of Coeymans limestone was measured. 
Manlius limestone.—From this horizon the 
subjacent rock undoubtedly belongs in the Man- 
lius. At the top is frequently a blue, thin- 
bedded limestone about 6 in. thick, which con- 
tains Leperditia alta (Con.) Hall. The color is 
dark blue like that of the Tentaculite limestone. 
This is No. 2 of Professor Harris’ section. Be- 
low is a Stromatopora bed which, on the cliff 
some rods to the east of the “‘ladder,’”’ varies in 
thickness from 13 to 24 feet. This is No. 3 of 
Professor Harris’ section which is 3.1 feet in 
thickness where he measured it, a quarter of a 
mile west of the ‘‘ladder,”’ while in the cut on the 
highway 4 feet was obtained and Spirijer van- 
uxemt Hall was noted. 
Dark blue, somewhat irregularly bedded 
limestone, the lower part of which is generally 
quite massive, but the upper 13 to 2 feet is 
thinner bedded and contains Leperditia alta 
(Con.) Hall. The thickness of this zone varies 
along the cliff from 5 feet, some distance east of 
the “‘ladder,” to 54 feet in Hartnagel’s section, 
6 feet in Harris’, where it is No. 4, and 6} feet 
in the highway cut. The most conspicuous 
lithologic break in this portion of the cliff occurs 
at the base of this zone; but the color of the rock 
and its fauna ally it more closely with the Tent- 
aculite than the Pentamerus limestone. 
Thickness 
of Zone— 
Feet 
ian 
Total 
' Thickness— 
Feet 
59+ 
56 
