jiOE — Silurian and Metamorphic liock^i. 141 



The boulder-deposit which, equally with limestone, marks the 

 junction-zone of the two great groups in parts of Donegal, is not 

 represented at Glencalry, while it is represented, as we have seen 

 though without limestone, at Erris Head. ' 



Fig. 4.-Detailed section at Glencalry, showing quartzite {q) invaded by epidiorite 

 over-ndden by mica-schist {m) and limestone {Is.), along reversed fault'. 



East of Belmullet the quartzite occupies a large area spreading 

 out so as to surround Carrowmore Lough, and form Glencastle Hill 

 (760), Knocknascollop (788), and Carrafull Hill (890), which is 

 separated by Bangor Gap from Knocklettercuss (1208), the north-west 

 spur of the Corslieve range (2369) : all the hills named consist of 

 quartzite. The divisional zone between the quartzite and mica-schist 

 below It IS marked as usual by a limestone band, which runs east by 

 south from Eelmullet to Eangor; and at the western end of 

 Carrowmore Lough, where the stream draining it issues, the quartzite 

 IS denuded to such an extent as to reveal the limestone accompanied 

 by a conglomeratic band, and the mica-schist beneath. This is shown 

 m the following section. 



^.-Section across Glencastle Hill and Carrowmore Lough (Wr 30) 



qurt2"r'"'''' '^'"'^ '^^"^^ ""'^^ 



It is of interest to note that a garnetiferous zone occurs in the 

 coarse gneiss, a short distance north of Binghamstown, near Belmullet. 



ZCtT" '^r'r ' ^^^^ Hmestone-zone east by south of 

 Belmullet on the shore, seems to indicate that the garnets are due to 

 th absorption of the limestone in this locality by the great intrusive 

 mass, which here strikes across Blacksod Bay. This coarse, pegmatitic 

 gneiss IS to be well seen in the vicinity of Binghamsto vn r and in 



