BIOTITE -MUSCOVITE-GRANITE. 317 



Tully mountains. Tlie di-ainage established itself toward the sides of the 

 basin and left these mountains in its center, as in the Orange- Enfield l)asin. 

 The result is that the contacts with the schists are everywhere concealed 

 beneath the brook deposits, and farther north by the till. 



From the highest ground on the road north from North Orange a fine 

 view is obtained of the deep basin, with the white granite showing in the 

 flanks of the Tully Mountains and all the ground above the sand level a 

 "felsenmeer" of great woolsack bowlders of granite, while the bold hill 

 in the extreme northeast of (Jrange shows by its jagged ridges of rust-brown 

 rock that it is made up of the liigher fibrolite-schists. 



The rock is the same almost purely biotitic granite as in the other bands, 

 in the northern portion beautifull}' "stretched" and slightly garnetiferous. 

 Along the side of Little Tully Mountain the biotite is mingled with epidote 

 in porphyritic blotches. 



SECRETIONS AND INCLUSIONS. 



I have described below (p. 332) the black biotitic secretions which 

 occur in the tonalite on either side of the river, and which resemble exactly 

 those found in this granite. They are formed by the accumulation of biotite 

 around centers. Other inclusions are more or less angular, and are finer- 

 grained and less micaceous than their host, or coarser-grained and black 

 from excess of biotite and hornblende. These seem to be portions of the 

 rock itself which have solidified before the rest and have been broken up 

 and floated to their present position, with more or less re-solution. 



There is in the first Massachusetts survey collection one specimen 

 from Wliately which contains a true inclusion of a foreign rock — a highly 

 pyritous muscovite-schist. 



THE HARDWICK GNEISSOID GRANITE AND GRANITITE. 



Reference may be made to the section in Chapter VIII having the 

 above caption for a preliminary description of this rock (p. 239). It covers 

 a much greater area in Worcester County than here, and its relations will 

 be more fully discussed in a memoir on the geology of that county. The 

 rock could have been described with perhaps greater propriety in this 

 chapter than with the Brimfield schists. 



The Coys Hill grauitite seems to me somewhat older than the other 



