638 



REPORT— 1901. 



as below, and the paper is concluded with a short discussion on the right to call 

 any of the American, Scottish, or Irish rocks the great complex. 



In a paper, 'A New Eeading of the Donegal Rocks ' (see ' Proc. R.D.S.,' vol. 



TU. 



(n.s.), part 9, p. 14 et seq.) and in the 'Manual of the Geology of Ireland,' hsts 

 of the Donegal and Galway and Mayo strata are given : the first we may copy; the 

 second lias to be modified "to come up to our present knowledge. These lists may 

 be tabulated for comparison. 



Gahvay and Mayo. 

 (Laurentian ?) 



Various gneisses, schist in places ; 

 zones of hornblendite. Large and long 

 intrudes of hornblende rocks, some ex- 

 cessively developed. These were in- 

 vaded by the Galway type granite and 

 its accompanying granitic gneiss. 



Base not visible. 



Over these a profound unconform- 

 ability. 



(Huronians or a newer Terrane.) 



The unconformable basement rock 

 is a conglomerate exceedingly altered, 

 various gneisses, schists, and quart- 

 zicic gneisses, with a few subordinate 

 limestones. In it are long intrudes of 

 hornblende rock, sometimes tremolite 

 rock, ophite, and elelagite. This Terrane 

 was invaded by the Omylite granite, 

 which usually is not accompanied by 

 granitic gneiss, but some of the outlying 

 long intrudes are, and in them is 

 immolated the basement conglomerate. 

 On the rocks of this Terrane are found 

 the basement great quartzites of 

 Terrane No. III. 



Donegal. 

 Tereanb No. I. (Laurentian ?) 



Granitic gneisses, micalitic quartzose 

 gneiss, and subordinate limestone. — This 

 Terrane was invaded by an albitic granite, 

 and it and other granites are solely ad- 

 juncts of the area not penetrating the 

 overlying basement great quartzite of 

 the Terrane No. III. 



BMe not visible. 



Tekbane No. II. (Huronians or a new 

 Terrane.) 



1. Gneiss, schists, many hornblendes, 

 with limestone zones, quartzitic gneiss, 

 and garnetiferous limestones. This 

 Terrane was invaded by the typical 

 porphyritic oligoclase Donegal granite 

 with its adjunct the foliated granite or 

 granitic gneiss, latter by other granites, 

 all older than the overlying basement 

 quartzites of Terrane No. III. 



Base not exjwsed. 



2. Gregory Hill schist series, a series 

 of various schists with below them beds 

 of hornblende rocks and one or two 

 limestones. In one place a fine gneiss 

 that seems to be metamorphosed felstone. 



Base not exposed. 



Profound micon form ability. 

 Tereane No. III. (Keweenawan ?) 



1. The basement strata are the great 

 quartzite with, under it in places, an 

 agglomerate but more often a greenish 

 rock, often quartzitic, in which are 

 scattered widely disseminated rounded 

 pieces of granite and gneiss from the 

 Terrane that may be under it (No. I. or 

 II.). Limestones or dolomites are also 

 found, but only in a few places. The 

 dolomites are associated with the 

 agglomerates, and may be methalosis 

 igneous rocks. 



2. Cranford limestone, dolomite, and 

 sericitic series. 



3. Lough Keel or Millford schist 

 series. 



4. Killygarvan volcanic series. 



5. Killygarvan quartzitic grit series. 



6. Lubber volcanic and limestone 

 series. 



7. Barn Hill grit series. 



Profound nnconforviability. 



1 . The basement stratum is a schistose 

 conglomerate under the great quartzite, 

 with which the conglomerate limestone 

 in places seems to be associated. 



2. Limestone, ophiolite, dolomite, 

 with schist underneath. 



3. Quartzite and micalite series. 



4. Streamtown limestone and ophio- 

 lite series. 



5. Micalite series. 



