Massive Crystalline Bocks. 169 



limestone in the field west of the road, and has the strike of the lime- 

 stone N. 47° W. But to the westward in the field (in which the 

 limestone can be traced for 250 yards with a change of strike to 

 N. 62° W.) the mica rock changes to hornblendite and quartz-diorite ; 

 and to the south-eastward along the road, augite-norite appears 

 within a few feet of the limestone, both the felspathic fine-grained 

 (almost cryptocrystalline) variety {Be), and the coarser dark variety. 

 Whether this latter change in the bordering rock is due to a fault or 

 not, could not be ascertained ; it was not due to an intrusive dyke. 



No. 5 outcrops on the railroad at 5 (see map) and on two roads at 

 5' and 5", with the strike N. 32° W. Between Montrose Station and 

 this limestone at o" , the rock is norite, excepting some greyish 

 augitic rock (Be) at the corner (Hunger's), where the road turns 

 west, and an outcrop of clirysolitic norite (hypersthene rock) 135 

 yards west of Hunger's. Eighty yards beyond the chrysolitic rock 

 comes the outcrop of limestone. One hundred and fifty yards west 

 of the small exposure of limestone on the north side of the road, a 

 ledge commences which extends along for nearly 350 feet, with no 

 dyke-like subdivisions. It consists mainly of norite, hut loitk some 

 hornblendite and norite -gneiss, and has distinct planes of bedding in 

 several places, all of which are conformable to one another. The strike 

 of its beds is N. 27° W., or nearly that of the limestone, and the dip 

 60° to 70° E. Part of the norite is garnetiferous. Figures 18, 19 



18. 



I 1\\ 1\ ^ /TTT 



ikW 



19. 



W 



^ 



represent the stratification observed in the ledge — Fig. 18 the 

 eastern portion, and 19 the western ; forty feet of earthy interval 

 separates the two. At the east end, at a, the rock (as a slice shows) 

 is hornblendite (with about equal proportions of orthoclase and 

 triclinic felspar), and it is schistose. It passes at the place to 

 coarsish quartz-diorite. At b, it is well-defined micaceous gneiss or 

 norite-gneiss, affording perfect observations of the strike and dip. 

 West of this the rock is mainly norite and augite-norite. At c, for 

 eight feet, black bands (or beds less felspathic than the rest) 

 alternate with the ordinary grey-black rock, and exemplify the con- 

 formability stated, though without divisional planes ; at d, are 

 divisional planes in the grey-black augite-norite, having the strike 

 N. 27° W. and dip 70° E. At e, is a much decomposed micaceous 

 gneissic layer (norite-gneiss apparently) conformable in strike, but 

 varying in dip from 40° E. to 60° E. ; at /, a distinct bed of light- 

 coloured very felspathic augite-norite, deeply decomposed, having 

 the conformability ; at g, or the west end, the rock is again mica- 



