468 NEW YORK STATE MUSEUM 
boundary of the Calciferous in a very narrow belt crossing the river 
at about Aiken and extending thence eastward in a broad belt to 
north of Crane’s village, with an outlier about two miles north of 
the latter place. The lower part of Amsterdam is colored as Cal- 
ciferous. The belt of Trenton on which Rockton is situated is 
represented as skirting the western bank of the Chuctanunda pass- 
ing near Hagaman, and to the west passing under the area of 
Utica to the west of Amsterdam and north of Aiken. A small 
patch of Utica is mapped north of Hoffmans. 
Accompanying the present paper is a map based on the Amster- 
dam sheet of the U. S. geological survey, and several profile sec- 
tions. One is a section along a direct line passing through 
the summit of Van Epp’s hill, Quarry hill, the Donlon quarry and 
a point just south of the Amsterdam secondary reservoir (Hoff- 
mans). The nature of the Hoffmans ferry fault is well shown and a 
slight syncline in which the Chuctanunda creek flows. This syn- 
cline is probably the cause of the peculiar distribution of the Tren- 
ton rocks in the city of Amsterdam. Another is a section along 
a line through the Moore-Walker quarries, reaching the Mohawk 
at a point one half mile west of Aiken. Some of the sections de- 
scribed are illustrated by the sketched position along this profile. 
This also shows the relations of the Utica and Hudson river terranes 
to the lower Silurian, specially the south dip of the strata and its 
effect upon estimates of thickness. 
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