666 



Report of the State Geologist. 



beds from ten to above twenty feet thick, averaging about sixteen feet. The 

 beds dip to the north and strike northeast, conforming in both respects with 

 the crystalline limestone in which they lie. The walls of the talc consist 

 of a tremolite or enstatite schist which passes over gradually into the 

 limestone. 



While, in mining, the talc is easily sejmrated from its walls, every possible 

 gradation exists between the two rocks, and it is evident that they are 

 different phases of one rock body. The schist probably has resulted from the 

 metamorphism of a siliceous and magnesian portion of the limestone, being a 

 product of the general metamorphism of the region. Subsequently, parts of 

 the metamorphic silicates have been altered into talc by addition of water 

 and loss of lime. This alteration, while most pronounced along certain hori- 

 zons in the schist, is more or less irregular, causing variations in the thickness 

 and precise location of the talc beds, which are further increased by 

 mechanical disturbances. 



Most of the Edwards talc shows the fibrous structure of the original 

 minerals and, in fact, as at the Fowler localities, contains a greater or less 

 amount of residual tremolite or enstatite. This is shown by tests of the hard- 

 ness of different parts of specimens, or, still better, by a microscopic exami- 

 nation. 



The formation of the talc by the process suggested (and discussed more 

 at length in the previous report) would not be a merely superficial pheno- 

 menon, like weathering, but would be the work of solutions which might 

 extend to great depths, and there seems to be no reason for fearing that the 

 deposits may be shallow and quickly exhausted. As a matter of fact the 

 weathered material at, and near the surface, is very poor, good talc appearing 

 only at some depth where it has been protected from the attack of superficial 

 agents. 



As it conies from the mines, the talc is white with a more or less intense 

 tinge of green. Its lustre is silky or pearly, and its structure decidedly 

 fibrous. Mingled, however, with the fibrous talc there is often some that is 

 scaly or wax-like. The latter variety is nearly always developed upon the 

 surfaces of the rather abundant slickensides. 



At the present time ten mines are in operation in the talc district, all but 

 one, that of the American Company described in the previous report, being 

 situated at Talcville. 



The product of the American Company's mine is ground by steam power 

 in a mill situated only a, few rods from the mine, but the other mines send 



