1894. | NEW YORK ACADEMY OF SCIENCES. 225 
include plentiful Maclurea magna a large species of Stromato- 
pora, some being eight to ten inches in diameter, large Ortho- 
ceratites Zaphrentis, ete. 
Stone from this quarry has been much employed in the vil- 
lage, in the sidewalks, stepping stones, etc. The polished sur- 
faces of sections of Maclurea magna and Orthoceratites, the lat- 
ter often very perfect and up two feet long, stand out conspicu- 
ously in white against the gray background, but are hard to ex- 
tract entire. 
TRENTON. 
The Trenton is much the most prolific fossil bearing forma- 
tion. It isa black, shaly limestone, usually quite thin bedded 
with alternating dense layers, and a low dip (4°-10°) to the 
north or northwest, often fractured by a slaty cleavage of 40°— 
60°. It first appears on the north in ledges up to fifteen thick, 
surrounded by the drift on the western shore at the head of Wills- 
boro’ Bay. Mr. van Ingen has identified some twenty-five spe- 
cies in the material collected at this point, as enumerated in the 
accompanying list. The surfaces of the slabs with which the 
shore is strewn are thickly studded with remains which weather 
out of the soft rock. Specimens of Chaetetes lycoperdon weather 
out completely in large numbers. 
Upon the lakeside the Trenton extends from about a mile and 
a half south of the mouth of the Boquet, where it first appears 
in the bed of a small brook, to a line just south of Essex village, 
where it is faulted against the Chazy. Calymene senaria, Orthis 
testudinaria, Bellerophon biobatus and Orthoceras are the most 
abundant fossils. Fragments of Asaphus gigas are also numer- 
ous, but not complete specimens, as are Lingula curta and 
another larger Lingula, graptolites and encrinal columns. The 
ledges can be traced in the bed of a small brook about a mile 
back from shore, and contain Lingula quadrata. The same brook 
curves around behind the blacksmith shop in Essex, and in its 
bed Calymene senaria, Orthis, etc., occur the same as on shore. 
At the south end of Essex village, near an old limekiln, the 
Trenton is faultel against the Chazy. The exact fault is ob- 
scured by drift, but the adjacent layers of shaly limestone are 
much crumbled and crumpled. The fault passes northwest- 
ward in all probability through the village, along the depression 
of the surface noted by Emmons. Emmons (p. 277) reports 
the occurrence of an outcrop of forty to fifty feet of Trenton 
limestone in the drift area at the head of Whallon’s Bay, and 
names unmistakable Trenton fossils found there. We were un- 
able to locate it, however. 
TRANSACTIONS N. Y. AcaD. Sct., Vol. XIIL., Sig. 15, August 8, 1894. 
