﻿1861.] 



HAKKNESS HIGHLANDS AND N. IRELAND. 



269 



In this arrangement of the metamorphic deposits of Donegal we 

 have an exact counterpart of the Highland series ; and this affinity 

 becomes still more apparent when we examine in detail the section 

 afforded by the N.E. coast of this country from Inishowen Head to 

 Malin Head, the extreme North of Ireland (fig. 9). 



Commencing at the S.E. end of this section, we have exhibited 

 the usual chloritic schists of the North of Ireland with the prevailing 

 S.E. dips, frequently the result of reversed flexures, which are nu- 

 merous in this district. This chloritic schist forms the Mountain 

 of Craignamaddy. Rocks of this nature extend north-westward to 

 the neighbourhood of Tramore Bay, where the quartz-rocks begin to 

 show themselves, having the usual S.E. inclination. These quartz- 

 rocks occupy the coast between Tramore Bay and Dunmore Head ; 

 and at the latter spot the chloritic schists again make their appear- 

 ance, the result of an anticlinal curve in the quartz-rocks, pushing 

 over the latter towards the N.W., and bringing in the small patch of 

 schist which forms Dunmore Head. 



Immediately north of Dunmore Head the limestones, dipping 

 under the chloritic schists, occur. These limestones of Culdaff are 

 not seen on the shore, owing to the district being low and covered 

 with sand. At a short distance inland they are very apparent, and 

 marked by flexures, which spread the beds over a considerable area. 

 The limestones here possess the prevalent S.E. dips. 



North of Culdaff large masses of trap are seen extending inwards, in 

 a W.S.W. direction, to beyond the village of Malin. On the line 

 of the section N. of these traps, another exhibition of quartz-rocks 

 occurs, intersected by other traps ; and this area of quartz-rocks 

 extends for more than two miles, after which chloritic schists again 

 make their appearance. This second mass of quartz-rocks with the 

 prevailing S.E. inclination has had its origin from the same circum- 

 stances which gave rise to the area south of Dunmore Head, viz. 

 from an anticlinal pushed over towards the north. These two areas 

 of quartz-rocks, separated from each other by the chloritic schists of 

 Dunmore Head, are seen in the district south-west of Cardonagh, and 

 they form the quartzitic area which is well developed on the east 

 side of Lough Swilly ; from whence they extend south-westward to 

 Lough Muck, and terminate in a point flanked on the N.W. by the 

 granite of the Derryveagh Mountains, and on the S.E. by the great 

 area of gneissose rocks. 



Continuing the section north-westwards, the chloritic rocks suc- 

 ceeding the quartz series are well seen at Glengad Head. They 

 also form the Mountain of Maheryard, and possess, as regards dip and 

 arrangement, like features to those of the masses of these rocks 

 which occupy the more southern area. A little to the north of Maher- 

 yard the quartz-rocks again appear, supporting the chloritic schists, 

 and have a continuous S.E. dip from the junction with the chloritic 

 rocks to a spot called Sandy Port. 



This latter surface of quartz-rock is much intersected by traps ; 

 and at Sandy Port a well-marked axis is seen, from which reversed 

 dips occur. Near this axis the quartz-rocks put on an aspect dif- 



