﻿Vol. 6 1.] ORDER OF SUCCESSION OP THE MANX SLATES. 363 



entirely separated from them by structures, seen in figs. 2 & 3 

 (below), 1 especially by the clearly-defined straight boundary seen in 

 the latter figure. 



On the evidence of the probable assumption, therefore, that the 

 Barrule Slates form a definite horizon, which is recognizable from 

 place to place, we establish the existence of an additional member, 

 namely, the Schistose Breccia, occupying a position near, or 

 at the summit of, the black slate. We thus have four consecutive 

 members definitely ascertained, composing the Manx Slates in 



Fig. 2. — Sketch of the folds in the overlying flags of Sulhy Glen. 



Fig. 3. — Junction of the Schistose Breccia with the overlying 

 rocks at the Salby-Glen Crags. 



ascending order : — The Agneash Grit, the Snaefell Laminated Slate, 

 the Barrule Slate, and the Schistose Breccia. There may be further 

 members of the same series developed locally above the breccias ; 

 indeed there appear to be signs of the existence of such, but no 

 adequate proof has as yet been worked out. 



III. The General Distribution of the Manx Slates. 



Considerable exposures of one or more members of the above- 

 described series of Manx Slates may be recognized in various parts of 

 the northern portion of the island (thanks to the Geological Survey- 



1 This is, apparently, the spot described in the Geological Survey-Memoir 

 (p. 62) under the words ' Every stage in the breaking-up of these sandy slates 

 and grits can be distinctly traced.' 



