in the vicinity of Great Barrington, Mass. 365 
and western section. “Tom Ball,” the highest summit of the 
range, lies directly west of Williamsville, and is by estimate 
750 feet in elevation above the plain either side. Its rocks are 
mica or hydro-mica slate and chloritic mica slate, like those of 
the Taconic range. Again, the town of Alford is divided lon- 
gitudinally from north to south by a low ridge of the same 
slates, 50 to 250 or 300 feet in elevation. 7 
may also state, as it will be necessary to make use of the 
fact in the course of this memoir, that a range, similar in rocks 
and altitude to the Tom Ball ridge, lies farther east along the 
eastern boundary of the town of West Stockbridge, and extends 
northward between Richmond and Lenox to the southern bor- 
der of Pittsfield. “Lenox Mountain ” is its highest part, and 
May well give a name to the ridge. All the ridges here men- 
tioned have an approximate parallelism to the Taconic range 
farther west 
The limestone region extends to the eastward of Beartown 
Mountain. I propose to continue my investigations of the 
Taconic and later rocks in that direction another season. How 
they spread east, whether anywhere to the Connecticut river 
valley or not, is yet among the unknown things in American 
geology. : 
2. Kinds of Rocks. 
The following rocks occur in the limestone region within 20 
miles north or south of Great Barrington. The beds of schist 
and slate either directly underlie, or are interstratified with, or 
Overlie the limestone; the quartzite rocks all overlie the lower 
F haeciirg stratum, but are sometimes interstratified with others 
ve. 
