110 Gregory —Igneous Origin of the " Glacial Deposits " 



appearance of the drift is that of a glacial deposit." In fact 

 several features ordinarily relied upon to establish the glacial 

 origin of surface deposits are present at Garnet Ridge. The 

 debris is accumulated in mounds or spread unevenly over the 

 surface. It rests in places directly upon the smoothed surface 

 of bed rock, and fragments of country rock are found in 

 abundance among the pebbles. The deposit is heterogeneous; 

 fragments of various materials, in sizes from that of the con- 

 stituents of rock flour to bowlders several feet in diameter, are 



Fig. 6. 











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P^*arf&"jj?*Vt ■■ 



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Fig. 6. General view of a portion of the ." glacial field." Garnet Eidge. 

 Eighteen varieties of rock fragments were collected within the area shown. 



confusedly intermingled ; and several of the larger bowlders 

 are perched in an insecure position. The constituents of the 

 drift are of a variety of shapes ; snbangular specimens are most 

 abundant ; some are rounded, many are angular. Cobbles with 

 smoothed faces and angular edges, also soled and snubbed and 

 polished fragments, are not uncommon, and a few striated 

 pebbles were seen. The conglomerate interbeclded with Juras- 

 sic (?) strata is identical in texture and composition with the 

 surficial drift. If the form and arrangement of pebbles be 

 emphasized, the materials described may properly be classed 



