;i74 The American Geologist. Juno, i«97 
In the 75th intercalation of shales Diphxjrajtlits nnuU'inanni apiiearB 
in f,'reat abundance, together with a few specimens of Enxloeeras pra- 
te if or me. The bearing is N. 82 degrees E., and the apices of the fossils 
point eastward. 
Above this shale, however, a layer of shaly limestone appears unex- 
pectedly, which consists largely of crinoid joints, fragments of InoteluH 
gigas and the brachiopods which apparently had disappeared far below. 
The rock has the appearance of typical Trenton. The next shale above 
abounds again in heads of Triarthrus. 
The 81st bed of shale proved to be rich in Tridrtbnis, Lingulu, Sehiz- 
oerania, and LeperdUia. 
The 87th bed abounds in heads of Triartluas and rhabdosomes of 
Diplograptm pristis. A few entire colonies of the same graptolite and 
young and old specimens of Conularid gnicilis occur. Bearing, due 
east. 
The 90th bed is full of shells of Llngula and LeperdUia arranged in 
long drift-lines, the latter running due east. 
The 92d bed of shales exhibits 19 surfaces, all covered with Diplo- 
graptutipristifi. These fossils are arranged in a due east direction on 
all surfaces, except three, which gave the readings N. 70 degrees E., N. 
70 degrees E., N. 65 degrees E. 
The alternation of shales with Utica slate fossils and more 
or less calcareous barren banks continues upward. That the 
shaly intercalations also reach farther down into the Trenton 
than it might appear from the exposure at the "Flat falls" be- 
comes obvious in the quarry at Ingram's mill, from which N. H. 
Darton* reports eight feet of limestone with shaly intercala- 
tions, on top of the exposed series of rocks. 
The conclusions which can be drawn from the observation of 
this alternation of shales and calcareous layers in the lowest 
Utica shale is that there were, for a long time, changing con- 
ditions which caused the water in this region to be alternat- 
ingly clear and then again turbid and moving. It seems also 
that the appearance of the turbid, moving water exterminat- 
ed gradual!}^ the clear water fauna of the Trenton and intro- 
duced new forms, more adapted to the muddy How. 
A similar series of successive shaly and calcareous beds 
was observed by the writer above Harris' quarry which is near 
Jfiddleville on the West Canada creek. The series, though 
not so well exposed as the above described one shows at least 
the occurrence of J)iplo(iraj)tus pristis in the shal}^ intercala- 
tions of the upper Trenton. 
*Rep. of the State Geol., 1893, p. 422. 
