160 NEW YORK STATE MUSEUM 



country rock on either side is a hard gneiss, containing very 

 little mica, though broken crystals of what appeared to be 

 biotite or phlogopite were met with. 



The remarkable feature of this deposit consists in the innum- 

 erable crystals of the so called pocket garnet with which it is 

 filled. These crystals are almost as abundant as cobblestones in 

 a bank of glacial drift; not by any means perfect crystals, but 

 coarse, irregular clusters, of which the matrix may be estimated 

 to contain from 10 to 15^ and in places 20^ of its volume, all of 

 deep red, irregular masses of mineral. They are found of all 

 sizes, from small bits up to enormous pockets, a foot or more in 

 diameter, and it is claimed that crystals of 3000 pounds in 

 weight have been taken from this mine. These large crystals, 

 however, are not permanently knitted together, for the decom- 

 position of the enclosing rock seems to have penetrated them 

 alfso, so that frequently the broken fragments can be picked 

 out easily with a stick, knife or trowel, and fall into the hands 

 of the collector as dull, ruby-colored, disintegrated masses. In 

 some cases huge crystals crumble so easily that a shovel full 

 of broken garnet can be taken from a single pocket in the rocks. 



The Warren county garnet^ occurs in a formation of crystal- 

 line limestone which appears to form the bed rock in the vicinity 

 of Minerva and in the gneissoid rocks which adjoin it. Prof. 

 J. F. Kemp finds, from specimens furnished him from the North 

 River Garnet Co.'s deposits, that the immediate associate of the 

 garnet there is a rock containing 60^ hornblende and a very 

 basic triclinic feldspar, probably anorthite. The following is 

 his description of the geology of these deposits as printed in the 

 Mineral Industry. 



The wall rock contains a large percentage of quartz, fully 50;^. 

 With it are oligoclase and small amounts of orthoclase, micro- 

 perthitic feldspar, hornblende, green augite and considerable 

 pyrrhotite and zircon. This is a not uncommon rock in this 

 section of the Adirondacks. Its granulation is due to pressure, 

 and all the above minerals are shattered and strained by moun- 

 tain-making upheavals. It was probably a rather feldspathic 

 sediment originally that became metamorphosed to a gneiss, but 

 it may have been a granite or similar rock now crushed and 

 granulated. The garnet bed must be either a metamorphosed 

 and originally impure limestone, which is most probable, or a 



^N. Y. State Mus. Bui. 15. p. 553. 



