424 NEW YORK STATE MUSEUM 
a mile below Amsterdam. . . Some of the layers at Amsterdam 
are referable to this mass as well as a large portion of the rock 
quarried at Schelpintown [Rockton]. In all these localities the 
color of the rock is gray, lighter or darker in some than in others, 
has a crystalline grain, rather tough. . . Some portions contain 
knobs, the result of accretionary action (p. 43). 
Then follows a detailed description of the “rock at Stanton’s 
quarry” (p. 44). 
In the final report of Emmons the Black river limestone receives. 
the name of “Black marble of the Isle la Motte’ and is characterized 
as the mass between the Birdseye and Trenton limestones, separated 
into several layers and having a total thickness of about 12 feet. 
It is often known as the Seven foot tier and is often lumpy. The 
fossil Columnaria sulcata is said to be quite abundant 
at Watertown, Glens Falls and Chazy.t In the volume on agri- 
culture the designation of this rock is “Isle la Motte marble,” and 
its thickness is given as “25 or 30 feet” at Isle la Motte ‘and 
“7 or 8” at Watertown where it is said to be lumpy.? 
Mr Darton makes very little mention of the Black river lime- 
stone but states that: 
In a smal! area near Amsterdam and in the Glens Falls 
region the Black river beds appear to be represented together 
with a heavily bedded member at the base of the Trenton. In 
a small stream emptying into the Mohawk opposite Amsterdam 
there is a three foot bed of coarse limestone of dark gray color 
containing corals, including Columnaria alveolata which 
I believe represents the Black river horizon. 
Trenton limestone. Prof. Eaton in 1824 described this rock mass 
under the name of “ metalliferous limerock”’ as a compact, gray, 
sometimes slaty, frequently cellular rock containing calcareous spar 
in scales and abundant fossils. The region under consideration is 
mentioned among the localities of rock (p. 81). 
In the First annual report on the geological survey of the third 
district the Trenton is called ‘‘ Blue fetid limestones and shales of 
Trenton falls ” with a thickness of about 400 feet. It is evident that 
part at least of the present Utica formation is included under the 
Geology of New York, pt 2, p. 110, 111. 
Agriculture of New York, 1:123. 
*13th annual report N. Y. state geologist, 1893, p. 424. 
*Geological and agricultural survey district adjoining Erie canal, 1824, p. 33. 
