﻿254 ME. C. I. GARDINER AND PROF. S. H. REYNOLDS ON [May I9IO, 



Arenig age, to.be described below (p. 255). We have found no 

 fossils in it, and an account of it is beyond the purpose of this 

 paper, but we class it with the grits and conglomerates found on 

 the northern side of the area as of ? Bala age. 



The eastern fault which brings a coarse conglomerate of probably 

 Arenig age against the tuffs of the area that we are describing is 

 nowhere actually seen, this part of the country being much obscured 

 by peat and drift. 



The Glensaul district is much more faulted than that of 

 Tourmakeady, as. in addition to the big faults bounding the area on 

 the east and west, it is cut in two by a system of faults which 

 have had the general effect of dividing the rocks into two principal 

 portions, and of shifting the western portion to the north-west, 

 and at the same time of introducing a wedge-shaped and much 

 faulted mass of country of complicated structure between the two 

 principal portions. 



However, despite the large amount of faulting, the general 

 succession of the rocks is easily ascertained, as they succeed one 

 another in regular ascending order from south to north, and dip, in 

 the main, regularly to the north-north-west at about 45°. 



At the outset of our previous paper dealing with the rocks of 

 the Tourmakeady district, the scanty literature bearing upon the 

 geology of that area is summarized l ; and, as in those descriptions 

 the Tourmakeady and Glensaul districts are invariably treated 

 together, we consider it unnecessary to repeat the references given 

 in our previous paper. 



At the meeting of the British Association for the Advancement 

 of Science at Dublin in 1908, a committee was appointed 2 to 

 investigate the igneous and associated rocks of the Glensaul and 

 Lough Nafooey districts in County Galway. A report on the rocks 

 of the Glensaul district was presented at the Winnipeg meeting in 

 1909. In that report the same general succession was given as 

 that described in the following pages. The Mount Partry Beds 

 were, however, referred to as of Arenig age and the Shangort and 

 Tourmakeady Beds as of Llandeilo age, the evidence which now 

 leads Mr. Reed to correlate these latter deposits in both the 

 Glensaul and Tourmakeady areas mainly with the Arenig rather 

 than with the Llandeilo Series not being then available. 



II. The Sedimentary Bocks and the Tuffs. 

 (a) The Mount Partry Beds. 



These rocks are finely exposed along almost the whole of the 

 southern side of the district, and the making of the new road to 

 Barnahowna has considerably added to the facilities for their study. 

 They consist of almost exactly the same rocks as iu the Tourmakeady 



1 Quart. Journ. Geol. Soc. vol. lxv (1909) p. 105. 



2 Consisting of Prof. W. W. Watts, Mr. H. B. Maufe, and the authors of 

 the present paper. 



