PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 593 



Chlorite schist.] 



Meg. A roughly schistose rock, gray, brownish and greenish in color. The 

 gray material is fine-grained quartz, the brownish contains a micaceous mineral, and 

 the greenish appears like the material of the green schists. The specimen was 

 collected to represent a transition between jaspilyte and green schist. 



Mic. The section shows various irregular, but more or less lens-shaped, areas 

 of three kinds: (1) Colorless, jaspilitic quartz; (2) Green chlorite, and'(3) Micaceous, 

 probably muscovite, areas rich in iron ore. Iron ore (limonite and hematite) is abundant 

 throughout the rock. The areas of different kinds are not always sharply marked 

 off from each other. The rock perhaps represents a schistose breccia of rocks similar 

 to Nos. 894 and 895. 



One section. 



Age. Keewatin. u. s. G. 



No. 896. CHLORITE SCHIST. (Siliceous,) 



Railroad cut at the Ely mine, Soudan. 

 Ref. Annual Report, xv, page 388. 



Meg. A fine-grained, brownish-gi-een, slaty and schistose rock. 



Mic. A very fine-grained rock composed essentially of the following minerals: 

 quartz, perhaps also feldspar, chlorite, iron ore and muscovite. 



One section. 



Age. Keewatin. u. s. G. 



Remark. In this slide are evidences that the iron ore is somewhat titaniferous. 

 These consist of the gray leucoxene substance in small masses. These sometimes show 

 the characteristic sagenite web resulting from alteration of rutile. Fine, interlocking 

 jaspilitic quartz, in individual grains, permeates the whole rock. N. H. w. 



No. 897. CHLORITE SCHIST (Jiolding pebbles of jaspilyte). 



Ely mine, Soudan. 



Ref. Annual Report, xv, pages 231, 268, 388; Bulletin vi, pages 233, 421. 



Meg. Fine-grained, green schist, having angular white areas of jaspilitic quartz. 

 The rock is similar to No. 889. There is one larger lenticular area of gray to reddish 

 jaspilyte an inch and a half in diameter included in the schist. 



Mic. The section shows chlorite, quartz, perhaps also feldspar, muscovite and 

 iron ore. The section resembles in general character that of No. 889. One section. 



Age. Keewatin. u. s. G. 



No. 898. CHLORITE SCHIST. 



Near Tower, but exact locality uncertain. 

 Ref. Annual Report, xv, page 388. 



Meg. Fine-grained, brownish-green, schistose rock. The brownish color seems 

 to be due to areas rich in a micaceous mineral and iron ore (probably limonite). 



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