‘ 
and the Northern part of New York Island. 435 
3. LivestonE AREA, NO. 3. 
A. The Limestone.—The main facts respecting this area have 
already been given, and I have little to add except the evidence 
with reference to its extension down Hariem River. The map 
shows its position south of King’s Bridge—its spreading over 
the Inwood Parade grounds,* the site selected for the proposed 
exposition of 1883—and its dividing into a western band which 
extends southward along the valley occupied by the King’s 
Bridge Road, the chief highway of Northern New York, and 
an eastern, of greater length. 
The western band I have not traced by outcrops beyond 
194th Street; but the valley is so well defined by its western 
wall of schist and its flat bottom that there is little doubt as 
to the continuation of the limestone to 187th Street, and it may 
not end short of 183d Street, where the valley fades out.t The 
most southern locality of limestone mentioned by Dr. Gale and 
Professor Mather is just north of the Inwood Presbyterian 
Church, to the north of which all the old quarries of the region 
are situated. 
r. Gale states, as quoted on page 519 of Mathers N. Y. 
Report, that “at th 
Avenue, the rock is entirely changed both in composition and 
structure; in composition it is a mixture of limestone and 
probably because of changes since made in t 
grading. The locality is nearly in the line that the western 
band would follow. 
The existence of an eastern limestone band down Harlem 
River is placed beyond question by the fact—made known to 
jami Chetek Resident Engineer in charge 
kK. These grounds lie directly north of Sherman’s Creek, east of the King’s Bridge 
ad 
_ + Within this limestone area, east of the Inwood “ Presbyterian Church,” there 
is a small isolated area of micaceous gneiss, having a nearly northeast strike. It 
crosses the King’s Bridge Road northeast of the church, and is about 225 yards 
long and 75 wide : 
e magnesian character of this King’s Bridge limestone was first determined 
by Mr. I. Cozzens, who states in his “Geological History of Manhattan Island. 
that it afforded him 28 per cent of carbonate of magnesia, and adds that he made 
epsom salts of it. 
_ ¢ The extremities of the bridge are left off in the copy here presented to reduce 
it to the length of the page, they being unessential to the illustration of the geo- 
ical facts. 
» 
