14 NEW YORK STATE MUSEUM 



its plasticity under pressure, the limestone is generally much folded 

 or twisted so that dips and strikes are very variable. 



As already stated, the actually observed limestone outcrops are 

 indicated upon the accompanying geologic map. 



Perhaps the most abundant variety of limestone is medium to 

 moderately coarse grained, nearly white, with irregular quartz 

 grains in varying amount up to 20 per cent, scattering flakes of 

 graphite (often with perfect hexagonal outlines) up to 4 or 5 mm 

 across, and sometimes tiny specks of pyrrhotite. ^lany big 

 exposures of such rock occur along Cedar river within 2 miles of 

 where it enters the quadrangle; in the vicinity of Indian Lake 

 village, and in and around Blue Mountain lake. 



Another variety is much like the above except for numerous 

 grains or small crystals of pale to dark green pyroxene (coccolite) 

 scattered through the rock. The pyroxene is often more 'or less 

 serpentinized. 



Still other variations are due to absence of quartz or graphite 

 from either of these varieties. 



Irregular shaped masses of pyroxene or hornblende gneiss have 

 sometimes been forced into the relatively plastic limestone under 

 pressure (see plate 4). 



Hornblende-garnet gneisses. Rocks of this kind are frequently 

 found in contact (or interbedded) with the limestone. The most 

 common facies is a fine to medium-grained, dark-gray gneiss con- 

 sisting of about equal parts of hornblende and feldspar and in which 

 are embedded scattering red garnets (almandite) up to three- 

 quarters of an inch across. Among the readily accessible exposures 

 are: one-half of a mile east of Indian Lake village; i^ miles south- 

 east of Forest House; and on the island one-quarter of a mile 

 northwest of Blue Mountain Lake village (no. 21, table i). 



A less common facies is somewhat similar to the above but has 

 some biotite and the scattering, rounded, red garnets (almandite) 

 up to 5 or 6 inches in diameter which are completely inclosed within 

 envelops of black hornblende crystals. This type of garnet gneiss 

 is exactly like that recently described by the writer as occurring 

 at the garnet mine on Gore mountain near North Creek. ^ Good 

 outcrops may be seen 2^ miles south-southeast of Forest House 

 in a small mine prospect. Better exposures occur in the old garnet 



1 Econ. Geol. Magazine, 7 ^5, 1912, p. 493-501. Also N. Y. State Mus. 

 Bui. 164, 1913, p. 95-103. 



