168 



THE :\IAr:QrETTE IIJOX-BEARING DISTIIICT. 



ORIGIN OF THK KITCUI SCHISTS. 



The Kitclii srliists are evidentU- frai;ineiital deposits. Their compo- 

 sition, liowevcr, is so dititereut from that of water-made sediments that we 

 must ascrilie some other origin to tliem. The banding of certain of the 

 conglomerates anil the ahernation of layers in some of the finer-grained 

 varieties would indicate tliat there Avas a ])artial sorting of the fragments, 

 but the nature of the fragments themselves, and the composition of the 

 matrix in which the>' lie, would seem to preclude the notion that the 

 materials were furnisheil ])V the wasting of preexisting rocks. 



In one or two of the several lumdred sections examined roundish 

 quartz grains were observed, but these are so verv i"are that they can aiford 

 no basis for a theorv of origin of the rocks containing them. 



The composition of one of the green schists (I) and of one of the sericite- 

 schists (II) associated with them is given below. The first is composed 

 largely of plagioclase, chlorite, and quartz: the second consists principally 

 of sericite and quartz. Both analyses were made by George Steiger in the 

 Survey laboratory. 



Analyses <>/ Kitchi schists. 



' Green schistose rocks speckled •svitU red-weathering feldspars. Xo. 22062. From near center 

 of sec. 34, T. 48 N., R. 27 W. 



" Light grayish-green sericitic schist from between two well-characterized conglomeratic l>ed8 

 of the green schist. No. 22085. From about 200 paces south of northwest corner of same section. 



