MAINE. 65 
North Blanchard. — There are two quarries at North Blanchard, both operated by 
tlio Lowell Slate Company. At the State of Maine or Blanchard quarry 50 feet of slate 
and quartzite, ten beds of each, in alternation, are exposed, and 200 or 300 feet more 
have been prospected east of the quarry. The quarry measures between 250 and 300 
feet along the strike, 40 to 50 feet across it, and 200 feet in depth. Both bedding and 
cleavage strike N. 25° E. and dip east-southeast at 80°. The slate has vertical dip 
joints striking N. 70° W. and diagonal ones striking N. 40° W., dipping 32° SSW. 
There are also joints confined to the quartzite, dipping 65° to 70° SSW., and also 65° 
to 70° NNE. The grain strikes N. 65° W. and dips 90°, almost like the dip join Is. 
The surface of the deposit is glaciated and covered with 10 feet of till. Some of the 
quartzite surfaces show faint traces of marine life. At the Moosehead quarry, which 
lies one-half mile southwest or south-southwest of the last, more than 65 feet of slate 
and quartzite are exposed. The thickest beds of slate measure 4 and 7 feet. The 
quarry measures about 500 feet along the strike, 50 feet across it, and 125 feet in 
depth. Bedding and cleavage both strike about N. 37° E. and dip east-southeast at 
80°. Dip joints strike N. 55° W. and dip 90°. The quartzite on the west side of the 
quarry is broken up by undulating horizontal joints from 1 to 4 feet apart. The 
grain corresponds to the dip joints. 
The slate from these quarries is a very dark gray. To the unaided eye the texture 
and cleavage surface are fine, but the latter is only slightly lustrous. The slate con- 
tains a little carbonaceous or graphitic matter and no magnetite, but the sawn edges 
show pyrite. No effervescence in cold dilute hydrochloric acid. It is very sonorous 
and very fissile. 
Under the microscope this slate shows a matrix of muscovite (sericite), with bril- 
liant aggregate polarization. A thin section parallel to the cleavage shows muscovite 
scales sufficiently numerous and parallel to produce a slight aggregate polarization. 
This may be due to an unusually pronounced grain. The quartz fragments occa- 
sionally measure 0.028 mm., and are not abundant. There are about one hundred 
scales of chlorite, interleaved with muscovite or sometimes biotite, to each square 
millimeter, with their laminae across the cleavage and measuring up to 0.066 by 
0.028; also, about seven biotite scales to each square millimeter, measuring up to 
0.085 by 0.047 mm., often bordered by secondary quartz or muscovite in the direc- 
tion of the slaty cleavage, but with their laminae transverse to it. There are about 
two hundred lenses of pyrite to each square millimeter, measuring from 0.004 to 
0.03 mm. in length and up to 0.01 in width; much dark -gray carbonaceous or gra- 
phitic matter in exceedingly fine particles; tourmaline prisms up to 0.07 by 0.009 mm. 
are plentiful. No carbonate or slate needles found. The chief constituents, arranged 
in descending order of abundance, appear to be muscovite, chlorite, quartz, pyrite, 
carbonaceous matter or graphite, and biotite. 
This slate is used for roofing and mill stock, including electric appliances. 
Brownville. — Only one quarry is now in operation at Brown ville, the " Old Merrill," 
operated by the Merrill Brownville Slate Company. This quarry lies less than a mile 
about northeast of the station (see PI. XII). Here are exposed 42 beds of slate 
alternating with as many of quartzite, and measuring altogether 165 feet in thick- 
ness. The slate beds range from 6 inches to 6 feet, and the quartzite beds from 6 
inches to 5 feet 6 inches. Any quartzitic slate is considered quartzite in these calcu- 
lations. « 
At the Hughes quarry, owned by the same company, but now idle, and situated 
a mile northwest of the Merrill, there are 28 beds of slate alternating with 28 of 
quartzite, measuring in all 161 feet 6 inches. The slate beds range from 1 to 9 feet 
and the quartzite from 4 inches to 20 feet in thickness. There is no evidence of 
duplication in these series of beds. Some of the quartzite is grayish and medium 
a Measurements obtained through the courtesy of C. H. Dunning, Supt. 
