596 MK. W. W. WAXIS ON IHE [Nov. 1 89 5,. 



its edges, and especially its ends, pass into a mass of granular 

 quartz with muscovite. Actually inside some of the grains granu- 

 litic patches occur, which I at first mistook for felsitic matter, but 

 which I am now compelled to regard as the products of crushing 

 and granulation. Fragments of striated felspar have been treated 

 in similar fashion, and slaty particles are flattened and dragged 

 out amongst the more resisting fragments. 



[E. 2419] is a similar rock, but it contains a larger range of rocks 

 as fragments, such as granophyre, etc., similar to those found in the 

 grauwackes of the Southern Uplands of Scotland. 



(3) The Dykes penetrating the Conglomerate. 



[E. 2390.] — Quarry at Kerroo Mooar, Sulby.* This rock, which has 

 the appearance of a diorite, consists of large irregular masses of 

 plagioclase (oligoclase or andesine) with both albite- and pericline 

 twinning ; the edges are very irregular. The granular matrix i& 

 chiefly made up of felspar, but it contains a certain amount of 

 quartz, which is associated with calcite, often in large grains. 

 Chlorite is now the sole representative of any ferromagnesian 

 mineral which may have been present ; it occurs in masses in which 

 the fibres are arranged in one direction, so as to yield straight 

 extinction. The rock is an altered diorite or dolerite, most probably 

 the latter. It is this rock which has effected the contact-alteration 

 to be presently described. 



[E. 2404.] — Dyke, east side of Sulby Glen, in the crags above 

 the bend at Glen Mooar. This rock is a much altered dolerite, in 

 which the felspars are largely converted into mica, while there is a 

 free growth of secondary felspar and quartz. The new felspar is 

 water-clear, and is sometimes twinned according to the Carlsbad 

 law. There are no prominent planes of shearing or cleavage. 



[E. 2405.] — Dyke, Glen Auldyn. This rock has entirely lost all 

 its igneous structure. It now consists of a cleaved and sheared 

 mass of mica, calcite, quartz, and limonite. It has probably been an 

 example of the greenstone type of rocks. 



(4) Metamorphism of the Crush-Conglomerate. 



[E. 2418.] — East side of quarry adjoining dyke [E. 2390], Kerroo 

 Mooar. The fragments in this rock are made of quartzose grit 

 rather coarser than the rest of the rock, which consists of very finely 

 granular quartz, with some felspar, and abundant muscovite- flakes 

 not arranged in any definite direction. The fragments have pba- 

 coidal outlines, and some of them are full of pyrites. The abund- 

 ance and size of the mica seem to indicate that contact-alteration 

 has taken place, and its irregular arrangement is quite independent 

 of the shearing of the rock. As might have been expected, 

 mica is much more freely developed in the slaty matrix than in 

 the grit-fragments. 



