374 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



rocks composed of soft calcareous schists, with subordinate harder 

 quartzose schists. The latter are most fully developed towards 

 the south-west on the Kintyre coast, between Stronchullin and 

 Slatefield, decreasing generally to the north-east. The islands 

 belong to the latter zone. From Liath Eilean (the light-blue 

 isle), near the mouth of Loch Gilp, we exhibit a piece of quartzose 

 micaceous schist, showing false bedding, or perhaps foliation lines, 

 and with an introduced vein containing chlorite. The mass of 

 this island consists of epidiorite, an altered basic igneous rock, 

 probably intrusive. It is crossed by a dyke of olivine basalt, an 

 unaltered igneous rock running north-west and south-east, probably 

 of Tertiary age, a specimen of which is shown. A piece of dolo- 

 mite, a crystalline limestone from a vein, is shown, and a bit of 

 quartzite from a block, none of it seen in situ. From Glas Eilean 

 (the grey isle), north of Otter Spit, we show a piece of quartzite 

 and two pieces of quartz schist, one of them much folded. The 

 two islands opposite Minard Castle, Eilean Aoghainn (lambs' 

 isle) and Fraoch Eilean (heather isle), seem to be composed 

 entirely of coarse epidiorite. Most of the upper part of Loch 

 Fyne has been hollowed out of the softer rocks of this 

 series. 



From the shore, and from the banks of the little burn, to the 

 west of Dundarave Castle, on the north-west coast of the loch, 

 are exhibited several specimens of quartz- schists with calcareous 

 matter in them, one with acute foldings. The knoll on the 

 water-edge, near the castle, doubtless the site of the original 

 "dun," or fort, from which is derived the name Dun-da-raimh 

 (rave) = " the fort of the two oars," is composed of fine-grained 

 epidiorite, apparently intrusive, a specimen of which is shown. 

 The epidiorite, being harder than the surrounding schists of 

 sedimentary origin, has resisted denudation better, and so stands 

 up as a knoll. 



This knoll and all the islands are more or less smoothed, 

 rounded, and grooved by the action of the mass of ice that in the 

 glacial period filled up Loch Fyne. The directions of the 

 markings run in the line of the loch. 



The " spit " of gravel and shingle at Otter (Gaelic, Oitir^ a pro- 

 jecting ridge or bank in the sea), which divides Loch Fyne into 

 "Upper" and "Lower," may be a moraine re-assorted by water, 



