J. D. Dana—Inmestone Belts of Westchester Co., N. Y. 359 
Art. XXXIX.— Geological Relations of the Limestone Belts of 
Westchester County, New York; by JAMES D. Dana. (With 
a Map, Plate V.) 
[Continued from page 220.] 
2. DistrRisuTION OF THE Betts or AREAS OF LIMESTONE. 
The limestone areas of the co ee sec the distribution 
shown on the accompanying map e V),“ the colored 
portions representing them. The Pesce surface is occu- 
pied by the crystalline schists—mostly mica schist and gneiss— 
as already explained. I have not attempted, in my study of the 
because my purpose was accomplished when their conforma- 
bility and their conformable relations to the limestone beds 
were ascertained, and the time I could command, without aid 
in he 
county. Moreover, the distinction of mica schist, micaceous 
gocieey thick-bedded feldspathic gneiss, hornblende schist, is, 
arts, of uo stratigraphical value, these unlike rocks, 
as bina been stated (p. 29), often occurring in alternations and 
graduating into one another in the direction of the bedding as 
well as transverse to it, rendering a correct mapping of their dis- 
tribution next to impossible. There are, however, areas of the 
hard feldspathic gneiss in which micaceous bands seldom 
laid Th estone areas often — as stated on 
29, more or less mica schist or gneiss, which is not indicated 
on the map, partly owing to the smnall iced of the map, but 
ived a 
The Tahaped aid on the map indicate the strike and 
~ of the beds, both of the limestone and schist; the top 
“This map, apart from its geological facts, is Colton’s pocket map of West- 
chester County da¥: ced one-half, with also the roads and most of the names of 
laces omitted. A slight change has been made in the coast west of Cruger’s, 
T-symbols with reference to all roads may be ascertained on comparison with 
Colton’s map. ; 
