﻿Vol. 6 1.] OKDEE, OF SUCCESSION OF THE MANX SLATES. 371 



as, for example, in the Hill Series, in which the outlines are very 

 distinct and clean, without any shading-off into the matrix. They 

 are often soft enough to be scratched with the finger-nail, yet they 

 end off in fine angles which the slightest shearing process would 

 have broken away. (2) Again, in Gob-y-Deigan Caves, the large 

 piece like Agneash Grit is much too hard to be touched by the 

 matrix in which the fragments are embedded, or even by the black 

 slates, and must have been rounded irregularly before being buried. 



But, though the bulk of the Schistose Breccias, as at Gob-y-Deigan 

 Caves, Druidale, Sulby, and Ramsey, and many others, show 

 characters incompatible with 'crush-conglomerate' or auto- 

 clastic rocks, there are also examples of the latter, as those 

 figured in figs. 2-5 & 11 in Quart. Journ. Geol. Soc. vol. li 

 (1895) pp. 568, 570-71, 582, which have been confounded with 

 the Schistose Breccia. 



The best, however, and most indubitable example of a true auto- 

 clastic rock or fault-breccia, is the example described long ago by- 

 Henslow, which Mr. Lamplugh appears to have missed, as he says 

 (Quart. Journ. Geol. Soc. vol. li, p. 563) of 'the headland south of 

 Gob-y-Deigan ' : — 



'It is here that the structure was noticed by Henslow. It is on the coast at 

 Ballanayre Strand, where a stream runs over the surface of some angular 

 fragments of clay-slate imbedded in a clay-slate paste .... sufficiently apparent 

 by the fragments assuming different tinges of colour.' l 



These expressions could not possibly be used of the Gob-y-Deigan 

 breccia, for there the fragments are perfectly distinct from the 

 matrix at all states of the tide; but at Ballanayre it is ' curious' 

 to see them only appear when wetted. In another part of the cliff 

 some thin bands of grit are separated and drawn out like the well- 

 known ' Belemnites ' of the Nufenen Pass. The locality is probably 

 a faulted one, as the Niarbyl Flags are seen nearly vertical in the 

 sea close by, and the position of the slates is probably the same as 

 that of the thin grit-bands, more nearly horizontal. In comparing 

 these two localities, Ballanayre Strand and Gob-y-Deigan caves, we 

 have an admirable illustration of the several characters which belong- 

 to each class of rock. 



Other examples figured, 2 not from the band of Schistose Breccia, 

 are from places where the rocks are so rapidly folded that parts of 

 the same band divide into obviously-connected fragments, all of 

 the same kind. These would probably be included among auto- 

 clastic rocks ; as also would the masses of unmixed fragments between 

 the contorted flags and the boundary of the Schistose Breccia, on one 

 side of the Sulby river, and a similar mass near the corner of the 

 road on the other side. Prom none of these examples can anywhere 

 passages be found into the mixed and widely-separated fragments of 

 the Schistose Breccias. 



In conclusion, I may be allowed to remark, that to make two 



1 Trans. Geol. Soc. ser. 1, vol. v (1820) p. 490. 



2 Quart. Journ. Geol. Soc. vol. li (1895)~pp. 570 & 582, figs. 3 & 11. 



