314 GEOLOGY OF OLD HAMPSHIRE COUNTY, MASS. 



scarcely any cliaug-e, except to call attention to the remarkably complex 

 system of veins at Great Falls, in Russell. He recurs as follows to the idea 

 quoted above: "And I have sometimes inquired whether, if the whole sur- 

 face were denuded as deep as that part occupied by granite, we should not 

 find this rock spreading over a great part of the State." 



In 1876 W. O. Crosby calls the granites of western Massachusetts 

 "exotic montalban granites, whitish or gra}', seldom red or greenish, as the 

 Huronian granite is always micaceous, seldom hornblendic," and yet in the 

 next section he classes the "syenite," which is generally reddish or greenish, 

 and hornblendic, witli the montalban granite. I am not certain that I 

 understand this classification. He says furtlier: "The Williamsburg granite 

 represents, I conceive, the extension southward of the Shelburne anticlinal, 

 only carried a step farther to produce the extravasated granite." An 

 inspection of the map will show that the Goshen anticline is the continu- 

 ation of that at Shelburne. There is no anticlinal structure connected 

 with the Williamsburg granite and mica-schist. 



In 1879 Julien publishes a most valuable article on the minerals of 

 the granite veins related to sjiodumene, containing much concerning the 

 secondary veins themselves which I have incorporated in my own descrip- 

 tion Ijeyond. 



BIOTITE-MITSCOVITE-GRAKITE. 



AREAS WEST OF THE CONNECTICUT. 



Characteristic for this rock is its fine, even grain. Biotite, the prevailing 

 mica, is scattei'ed in small, separate, jet-black scales in a fresh, bluish-white 

 mixture of quartz and feldspar. This gives it a deceptive similarity to the 

 granitic forms of the Becket gneiss, from which it is distinguished by its 

 greater firmness and by a small, constant content of muscovite. It resem- 

 bles the granite of Concord, New Hampshire. It may be best studied at 

 the quarries east of Florence. In its finest varieties, as at the Loud\'ille 

 mine, it is almost a petrosilex ; in its coarsest, as at the quanies above, the 

 grains reach 2-3""". It is wholly wanting on the east side of the river, 

 around the Belchertowu tonalite, which is in immediate proximity to the 

 Monson gneiss. 



DISTRIBUTION. 



Just east of the Florence quarries, and extending from the house of 

 Mrs. Haley to that of W. N. Moore, this granite adjoins the tonalite. In all 



