﻿Vol. 66.] THE ORDOYICIAN OF THE GLENS AXIL DISTRICT. 



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'. (3) Between the two principal masses of felsite. — Here 

 is a triangular area of Mount Partry Beds, bounded by faults on 

 every side. The rocks are ill-exposed (except in some small water- 

 courses), and consist mainly of coarse grit, but cherts are also 

 to be seen. 



Pig. 1. — Tuffs and banded cherts of Arenig age, exposed in a 

 road-cutting south-west of Greenaun. The rocks are much 

 disturbed. 



(b) The Shangort and Tourmakeady Beds. 



As in the Tourmakeady district, the Shangort Beds consist of a 

 series of more or less gritty tuffs enclosing calcareous bands of 

 variable character comparable with those described as the Tour- 

 makeady Beds in our previous paper. The Glensaul succession, 

 however, differs from that in the Tourmakeady district in the much 

 more frequent occurrence of very coarse breccias, and in the con- 

 siderable development of well-marked calcareous bands, which 

 sometimes pass into nearly pure limestones, but are, as a rule, 

 highly calcareous grits or grittv tuffs, differing from some of the 



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