194 J. D. Dana—Geological Relations of the 
Art. XX V.— Geological Relations of the Limestone Belts of West- 
chester County, New York; by JAMES D. DANA. 
[Continued from page 32.] 
(4.) Hornblendic, Augitic, and other associated Rocks not in- 
cluded in the preceding subdivisions. 
Tur hornblendic and associated rocks referred to in the 
above title cover a large part of the township of Cortland— 
the northwestern of Westchester County — between Croton 
River on the south, and the parallel of Peekskill on the 
north, an area of about 25 square miles. They differ widely 
from the ordinary rocks of the county, and may well be des- 
ignated the Cortland series. In fact, a series so remarkable 
in constitution, so diversified in kinds and so full of geological 
interest is seldom found together within so small an area any — 
where on the globe. They reach the banks of the Hudson 
just south of the Peekskill railroad station, and at several 
points beyond; yet considerable portions of the shore region 
are occupied by narrow strips of common kinds of mica schist 
and gneiss, and occasionally limestone. Leaving Peekskill by 
South street, near the river, the first ledges (north and south 
of Hudson street, 4, on the following map), consist of one of 
the rocks of the series; and to the eastward of the village, 
on the road leading southeast, only half a mile from the Acad- 
“<a f grounds (adjoining which, on the street north, an evenly 
ed mica schist of the limestone series outcrops), the same 
rocks occur. The western boundary of the town is passed by 
the Cortland rocks only south of its middle point (below Mr. 
trang’s), for a distance of a little over a mile. 
South of Verplanck they extend to the Hudson, and are 
the rocks of Montrose Point and the northern portion of Cru- 
_ ger’s Point. Just here the river becomes narrowed to one third 
of its width through the projection of these points and of an 
equally prominent headland called Stony Point on the oppo- 
site side. This isolated east-and-west ridge consists of rocks 
related to those of Montrose and Cruger’s Points, and there is 
little doubt that it was once connected with the Montrose re- 
gion. It is the only locality of the rocks yet observed on the 
western side of the Hudson 
The accompanying map of the western portion of the town 
of Cortland, between Peekskill and Cruger’s, together with 
the Hudson River adjoining, contains the places here referred 
. Its scale is an inch to a mile. 
The occurrence of limestone areas in close proximity to the 
rocks of the Cortland series is a fact of special interest, as is 
