THE SOUTHEHN COMPLEX. 121 



XTV, Fif^s. 3 and 4) between the Potato river and tlic West l^rancli of the 

 Montreal (pp. 109-111). 



Thev will, then, not b(^ described in detail here again. It will be 

 remembered that they contain numerous large jjlagioclase feldspars, within 

 which are l)lades of hornblende and particles of (piartz. In case the feld- 

 spars are larg-e and the alteration has proceeded far, within a single individ- 

 ual may be found many grains of qiiartz and blades of hornblende. It will 

 alst» be remembered that the hornblendes have peculiar jagged terminations, 

 which are shown in a marked degree when the sections are longitudinal, but 

 are also observable in transverse sections. It was noted that they might, 

 with almost equal plausibility, be regarded as of eruptive or sedimentary 

 origin. In the Eastern green schist these rocks have, however, been traced 

 step by step into those which are almost certainly of an erujrtive origin. 

 This rock in hand specimen in one case is massive, and has strongly the 

 appearance of a massive basic eruptive. Within the same exposure are 

 other phases of rock which have the distinct foliation of the hornblende- 

 gneisses of the region. These rocks and others within the localitv under 

 consideration have almost no quartz, the bac-kground being composed of 

 large areas of feldspar, which intricately interlock. Between these feld- 

 spars and in them are many liornblendes of varying sizes, individuals fre- 

 quentl}' being large. They have the same jagged outlines which are char- 

 acteristic of the hornblende already alluded to. The sections also contain 

 much comparatively fresh magnetite. There can be little doul)t that this 

 massive rock is a modified eruptive, or that the schistose one from the same 

 exposure is of the same character. As there is every phase of gradation 

 between this massive rock and those schistose ones in which there is a large 

 amount of quartz jH'esent, it is exceedingly probable that all of this class 

 of hornblende-schist is eruptive, although, as before, I would guard mvself 

 by saying that we have no absolute ))roof of this. 



Between the two main kinds of rock above described there are all inter- 

 mediate phases. 



Besides these phases of rock there are manv subordinate varieties. It is 

 worthy of remark that in one of the fine grained schists which is found in 

 large exposures a background of very finely crystalline quartz and chlorite 



