﻿JB. W. Clarke— Zithia Micas. 353 



Art. XL. — Researches on the Lithia Micas f* by F. W. Clarke. 



I. The Lepidolites of Maine. 



Lsr the western part of Maine, along a line running south- 

 easterly from the Kangeley Lakes to a point on the seaboard 

 between Brunswick and Portland, there are a series of veins 

 of albitic granite which are noted for their contents in lithia 

 mica and colored tourmalines. These localities, in the towns 

 of Kumford, Paris, Norway, Hebron and Auburn, are all 

 within a narrow belt of about forty miles in length ; and with 

 them, as a probable part of the same system, may be classed 

 the spoclumene locality in the town of Peru. The northern- 

 most of the known localities is that on Black Mountain in 

 Kumford; but a few fragments of inferior green tourmaline 

 have been found about five miles farther north, in Eoxbury — 

 a fact which indicates a prolongation of the belt in that direc- 

 tion. Similarly, a southern extension of the belt is suggested 

 in the territory covered by the towns of Pownal, Yarmouth 

 and Freeport, a region from which a few casual specimens of 

 lepidolite have been reported. The total width of the belt, so 

 far as has been observed, appears to be not much over fifteen 

 miles, although sharp definition of the area is not yet possible. 



In general character the several localities are much alike, 

 although in points of minor detail they vary considerably. 

 With the tourmaline and lepidolite, quartz, muscovite, cleave- 

 landite, cassiterite and amblygonite are always found, together 

 with a wide range of other species which cannot be considered 

 here. Some of the differences are probably due to the fact 

 that certain localities have been more thoroughly opened up 

 than others, and these differences would probably be elimi- 

 nated by more complete exploration. In other points, how- 

 ever, the variations are notable and characteristic. For con- 

 venience we may briefly consider the several localities sepa- 

 rately, beginning with the northernmost and proceeding south- 

 ward in regular order. 



Rumforcl-f — This locality, discovered in 1878 by Mr. E. M. 

 Bailey, of Andover, Maine, is situated on the northern slope of 

 Black Mountain, at an estimated elevation of about one thou- 

 sand feet above the valley. The excavation, so far, has been 

 merely superficial. A part of the lepidolite, which is very 

 abundant, is fairly pure, lilac-purple in color and finely granu- 

 lar; but the larger portion of the mineral is coarser in struct- 

 ure and thickly sprinkled with small, opaque, red tourmalines. 



* Abstract of a paper to appear in full in a forthcoming Bulletin of the U. S. 

 Geological Survey. 



f See G-. F. Kunz, Proc. Amer. Assoc, 1885. 



