118 Trof. Dana — MetamorpMsm of Massive Crystalline Rocks. 



Fig. 12. 



up the slope. Between three and four yards of the band are repre- 

 sented in Figure 12, As shown, it is in pieces ; yet the pieces are 

 not much displaced, which they would be in an erupted rock. The 

 material is greyish-black, and consists of a very chloritic magnetite, 

 with a little black mica, in a feeble amount of base of triclinic fel- 

 spar. After an interruption it appears again for a short distance to 



the westward, where it is much 

 more micaceous and garnetifer- 

 ous ; but the exposure is not as 

 satisfactory as in the case of the 

 other bands. Three feet behind 

 this band, that is, to the north, 

 there is a similar one having 

 a parallel position. 



Eight or nine yards north 

 commences the coarse diorite. At the top of the slope, near the 

 passage of the coarse diorite to the soda-granite, partly in the diorite 

 l)ut mostly in the granite, there are three bands (h) within three to 

 five feet of on€ another, gneissic in constitution. Figure 13 repre- 

 sents about a dozen yards of these bands, in the diorite and granite. 



Fig. 13. 



Fig. U. 



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Vv\7S 



The upper or northern of the three bands (6^) is exposed with small 

 interruptions for a length of more than one huiidred and fifty feet ; and 

 the more eastern portion is shown in Figure) 14. The strike is the 

 same as that of the schist. 



The rock of the middle of these bands (Ir) is a quartzose gneiss, 

 with black mica, many visible grains and octahedrons of magnetite, 

 and some garnet — resembling the gneiss of some of the nearest schist 

 and unlike the inclosing soda-granite in its excess of quartz, mag- 

 netite, and its garnets ; and that of the others is similar. About 

 three yards north, but a little to the west, is another band {¥), one 

 to two inches thick, which has a grey colour, and consists of small 

 spangles of silvery mica, some scales of black mica and chlorite, and 

 grains of mag-netite — a thin layer of the mica-schist more magnetitic 

 than usual. 



About eight yards north of the third of the bands represented in 

 Figure 12, there is another schistose band (c), which is short in the 

 line of the section, but appears again to the eastward and also to the 

 westward ; the rock is quartzose, garnetiferous, and includes chloritic 

 magnetite with fibrolite, and other materials of the schist. 



