3i8 The American Geologist. November, i898 
siderably thicker deposit first accumulated, but was largely 
reabsorbed during an interval of non-deposition. The re- 
absorption left the surface irregular and the top of the stra- 
tum saturated with oxide of iron and manganese. Extreme 
irregularities of the surface may have given origin to loose 
isolated blackened pebbles, or the same may be parts of a 
broken up stratum or lamina, reduced by absorption like the 
ground surface. The existence of these pebbles through the 
stratum above and beneath the black seam indicates that 
more than once such periods as the blackened surface repre- 
sents, had obtained, but that the result of their existence, the 
black surfaces had been later broken up. The association of 
fucoids with the pebbles may indicate that the latter were 
sometimes transported by the former, wl],ich their proportion- 
ate size would seemingly also indicate. 
The above described strata lie at the base of the Buff lime- 
stone bed at the bottom of the series, (see plate IX). This bed 
is about thirteen feet thick excluding the transition strata just 
described. The top of the Buff limstone bed has also a black 
stained irregular semi-polished surface, upon which the first 
laminee of the succeeding bed, the Bellerophon bed, rest in a 
sort of non-conformity on a small scale. The limestone strata 
part along this plane and its existence is often obscured by 
vyeathering, but again in many places one can observe well 
how the upper limestone penetrates the small irregularities and 
borings in the blackened surface of the lower one. Again the 
Bellerophon bed has the upper surface of its top stratum irreg- 
ularly sculptured and blackened. Here there is often a dis- 
continuous lamina with its surface also blackened and bored, 
resting upon the main surface. The first succeeding stratum, 
belonging to the Stictoporella bed, is usually limestone but a 
shaly carbonaceous thin layer here and there intervenes. 
Black pebbles, such as are abundant near the first, or low- 
est corrosion zone are not observed with the second and third. 
But the fourth one which is in the top of the Stictoporella bed 
(plate IX) has on the contrary pebbles, and not a continu- 
ous blackened surface associated, at that place. In the top- 
most laminae of this bed, among numerous fossils, are flat 
irregularly moulded pebbles about one inch in width and 
smaller. The Stictoporella bed is mainly composed of clay 
