PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 827 



Graywacke.] 



No. 2031. GRAYWACKE. (Arkose. ) 



N. E. % sec. 24, T. 66-6, Oak Lake portage to Saganaga lake. 

 Ref. Annual Report, xxiv, page 18. 



Meg. Coarser-grained portion of the rock near the landing at Saganaga lake. 

 Appears like granite, but varies from coarse to fine in not very evident alternations. 

 Greenish gray and gray. (Compare No. 322.) 



Mic. Feldspar and quartz in a mixture like a graywacke with a cement like 

 that of No. 2027, i. e., largely of scricite and calcite. One section. 



Age. Archean (Upper Keewatin). N. H. w. 



No. 2032. GRAYWACKE. (Arkose.) 



Same place as No. 2030. 



Ref. Annual Report, xxiv, page 18. 



Met/. Some of the finer portion of the same rock. 



Mir. This rock differs from the last in having fewer of the entire crystals, or 

 large fragments, and a very abundant supply of the finer detritus. One section. 



Age. Archean (Upper Keewatin). 



Remark. The rock at this portage has been mentioned as granite by several 

 geologists. N. H. w. 



No. 2033. GRAYWACKE. 



Apparently as fragments in rock like Nos. 2031 and 2032. In Ontario, about two rods north of the portage 

 (which is in S. E. % N. E. J sec. 24., T. 66 6 W.) between Oak and Saganaga lakes. 

 Ref. Annual Report, xxiv, page 19. 



Meg. Apparently similar to Nos. 2031 and 2032, but very much finer grained. 

 The rock is of a light yellowish-green color, but weathers to a brown. One side of 

 one of the specimens shows a small area of coarse-grained rock. No section. 



Age. Archeau (Upper Keewatin). u. s. G. 



No. 2035. GRAYWACKE. 



About five rods east of No. 2034 ; in Ontario. From a surface which appears to be ripple marked. 

 Ref. Annual Report, xxiv, page 20. 



Mey. Similar to No. 2032, but more weathered and consequently yellowish in 

 color. No section. 



Age. Archean (Upper Keewatin). u. s. G. 



No. 2037. GRAYWACKE. 



Below the ripple marks ; same place as No. 2035. 

 Ref. Annual Report, xxiv, page 20. 



Similar to the general rock here (Nos. 2031 to 2036), but somewhat finer 

 grained than usual, and showing rusty specks. No section. 



Age. Archean (Upper Keewatin). u. s. G. 



