236 C. CALLAWAY OZT THE GEAXITIC AJTD 



miles, we have the micaceous and talcose (or chloritic) schists. 

 They are frequentlY folded, and in addition are intensely crumpled 

 in numerous small contortions. The dips are alternately X.W. and 

 S.E., but sometimes there is more north or south in them. These 

 schists are frequently penetrated by intrusive diorite. Towards 

 Lag, quartz-schist and quartzite come in, and quartzose rocks are 

 found as far west as Mahn Head. 



. The rocks of Malin Head are on the strike of the quartzite^ of 

 Dunaff Bay, and are composed of quartzite and quartz-schist. 

 They are bent into an anticline, well seen at Esky Bay. On the 

 south side of the headland, I saw a mass of hornblende-schist, which 

 had apparently been forced up amongst the quartzites by the intru- 

 sion of the granite. The extremity of the Head, which is the most 

 northerly point of Ireland, is coroposed of flaggy quartz-schists, 

 greatly contorted, plunging vertically down to the west. 



Comparing the mica- schists of this traverse with the similar rocks 

 in the last section, we find the alternating dips west of Malin 

 represented on Lough Swilly by a tolerably uniform dip to the S.E. 

 The great apparent thickness of strata on Lough Swilly may there- 

 fore be explained by repetition. 



Section between the Granite of Croagli and the Diorite of Horn 

 Head {Dimfanaghy), (Pig. 6, p. 235.) 



The metamorphic rocks of Lough Swilly and Malin are only the 

 upper portion of an extensive succession. Lf the quartzite of Dunree 

 Head be followed on the strike to the S.W., it is seen to coincide 

 with the quartzite ridge of Lough Salt, where it is underlain 

 (p. 224) by schists and limestone. These are the lowest rocks east 

 of the granite promontory'. 



West of the granite of Croagh, we pass through a succession of 

 micaceous and hornblendic schists, underlain at Lough Xatooey South 

 by bedded crystalline limestone with seams of mica and some quartz, 

 the dips being usually to the S.S.E. at 80". There is a general 

 resemblance between these rocks and those east of the granite, but 

 the dip is much higher and is occasionally vertical. 



At Creeslough there is an apparent thickness of several hundred 

 feet of well-foliated mica-schist, dipping conformably with the pre- 

 ceding rocks. Omitting numerous masses of diorite, we find the 

 following descending succession between Creeslough and the coast. 



Stream east of Derryharriff. — Mica-schist of the lustre and colour 

 of black lead. 



South of the E. C. Chapel at Doocashel. — Similar schists, diiDping 

 S.S.E. at various angles, some low. 



East of Chapel. — Quartzite with low S.S.E. dip. 



Bridge south of Ballymore Church. — Quarry of coarsely crystalline 

 massive limestone. Colour white; some bands blue: the former 

 sometimes with folia of mica. Dip S.E. at 40°-50^, 



Eoad north-west of Church. — Quartzite with low dip or horizontal; 

 in places greatly contorted. 



South of Faugher Upper. — Quartzite. 



