562 THE GEOLOGY OF MINNESOTA. 



[Conglomerate. Shale. 



No. 827. CONGLOMERATE. 



Taylor's Palls. 



Ref. Annual Report, x, page 119. 



Meg. A rough, porous conglomerate, gray, yellowish, brownish and greenish 

 in color. It contains pebbles and fragments of decayed diabasic rock, some of which 

 is amygaloidal. 



Mic. The section was evidently made from one of the pebbles. It shows a 

 decayed, fine-grained, diabasic rock in general similar to No. 823. 

 One section. 



Age. Upper Cambrian. u. s. o. 



No. 828. CONGLOMERATE. 



Taylor's Falls. 



Ref. Annual Report, x, page 119. 



Meg. The matrix of the specimen is porous, is brownish in color, containing 

 considerable iron oxide, and is largely composed of quartz. Pebbles, of all sizes up 

 to an inch across, are common. They are sub-rounded or rounded. They consist 

 of various materials, among which are quartz, fine-grained, diabasic rock, quartzyte 

 and shale. 



Mic. The matrix is of rounded and sub-rounded grains of quartz, with more or 

 less confused opaque materials. The pebbles are of indefinite character, being mostly 

 masses of nearly opaque materials. 



One section. 



Age. Upper Cambrian. u. s. G. 



No. 829. CONGLOMERATE. 



On the St. Croix river, a mile and a half below Franconia. 

 Ref. Annual Report, x, page 120. 



Meg. The specimen shows a coarse conglomerate, the pebbles being greenish- 

 gray in color and apparently formed of much decayed basic Keweenawan igneous 

 rocks. The matrix of the conglomerate is fine grained, brown in color, and holds 

 numerous fragments of Lingula shells. 



Mic. The section is small and is much stained and impregnated by li<'iii1it<: 

 Besides the hematite it consists largely of what appear to be much altered, nearly 

 \aoteopicfeldspar laths. In addition there are some very minute, brightly polarizing 

 grains (epidote?). The section appears to be that of a highly altered diabase. 



One section. 



Age. Upper Cambrian. u. s. G. 



No. 830. SHALE. (Soft.) 



Sioux Falls, South Dakota. 



Ref. Annual Report, x, page 120. 



