60 REPORT— 1864. 



result of my observations I liave thought right to lay before the British Associa- 

 tion, apologizing- for the meagre story I have to tell. This poverty arises partly 

 from my resolve to devote all the time possible to zoological work, and partly from 

 the very small portion of the islands visited. Our first landing was at Lerwick, 

 where little time was spent, either then or when returning. In a short walk that 

 I took in the immediate vicinity of the town, at the Bay of Sclate, I found the 

 sandstone on the top of the clitf deeply rutted, striated, and polished ; and a little 

 inland, on the side of the famed Loch of Clickamin, similar markings. These 

 markings are again to be seen on the opposite side of this bay. The ruts, &c. are 

 all in a north and south direction, with slight deviations to the east and west. The 

 direction the drift came from is e-\ idently northerly, and may be traced up the 

 valley, as shown by the wide-spread ruin and large blocks scattered all over it, 

 resting on striated and polished rocks. The hills on each side of this valley and 

 those at the head beyond the docks bear unmistakeable evidence also of gi-inding 

 and polishing. After leaving Lerwick the Out-Skerries of Whalsey became our 

 home. The three small islands forming this group lie far out in the sea ; they are 

 called Gruna, Bruray, and Housay. There is an excellent harbour here, having 

 two good entrances for vessels and boats, and a third into which boats can run 

 when the tide answers. These entrances are triradiate, the harbour being in the 

 centre, sheltered by the three islands from every wind. They have been the scene 

 of great grinding, all being more or less rounded, — roches-vioutonnees form of 

 knolls being abundant, — whether composed of granite, gneiss, quartz, or limestone, 

 all these being intermingled throughout the group. Although much corroded by 

 atmospheric action, and the limestone much more acted on by sea-water, the 

 roundmg can be everywhere seen. By these agents the ruts, striae, &c. are thus 

 generally obliterated, and they are also further obscured by an overgrowth of 

 lichen. I Avas fortimate enough to find a recently-bared rock near the Mill Cove 

 on the island of Housay, from which I further removed the drift and washed the 

 stone, and here ruts, striae, &.nii polishing could be as plainly seen as if just done. 

 I also foimd on the highest part of this island, on a gneiss rock, some deep ruts and 

 scratches, which, with those at the Mill Cove, ran nearly E. and W., this being the 

 direction of the channel of the two principal entrances to the harbour which sepa- 

 rates Gruna from Bruray. The clitf on the north side of the Mill Cove of Housay 

 is about 200 feet high ; the sea breaks on the top of it in heavy gales, and tears 

 up the rock, and also throws up material from the deep. So great is the force, that 

 large blocks are driven far back, a considerable distance from the edge of the clift", 

 into a semicircular-like wall. Between this wall and the clift' a deep river-like 

 gully is scooped out, down which the water rushes again to the sea, at a great dis- 

 tance from the spot whence it was thrown up. The water left in depressions in this 

 grdly is brackish, and in it Enteromorpha grows. Mr. Jefii-eys and myself gathered 

 portions of limpets, mussels, periwinkles, rock whelks, and other sea shells, amongst 

 the sand and gravel, both in and on the edge of this gully. The whole of the top 

 of this cliff (much of it is now beyond the mfluence of the seas of the present day) 

 is also strewn yn\.h. proofs of similar action, some of the stones hanging in ridges 

 on the rounded sides of the hill. All these loose blocks and stones rest on rormded 

 knolls and polished rock — all so polished before the burthen they now bear was 

 thrown on them. Although I know of many gi-and instances of such recent ruin 

 both in Caithness and Orkney, this far exceeds them all. Every season the terrific 

 seas which break on the whole of these islands, leave traces of their power of the 

 most astonishing kind. As well as the markings on the rocks, I met with several 

 deposits of drifted matter, in which rounded, striated, and smoothed stones were 

 not vmcommon. Some of these deposits were from 12 to 14 feet in depth. 

 Perched blocks, but not in abundance, some of large size, were scattered over the 

 whole group. Our next move was to North Unst, Baltasound being our head- 

 quarters. Here too the eft'ect of glacial action was plainly to be seen. The ser- 

 pentine rock had suffered seriously, and although much acted on by weather, the 

 rounded outline of the hills and knolls teUs clearly of the grinding they had been 

 subjected to. Ruts and stricB are also rare here. They, however, fell tu:der my 

 notice on the clitf' at Hagdale in Haroldswick Bay, on a recently bared rock un- 

 derlying a thick deposit of drift, in which rounded and striated stones and blocks 



