66 REPORT 1851. 



before stated. From the above facts it appears, that the action of those currents which 

 brought the principal mass of crag to th.is spot, and which had power to convey to it 

 some stones of no ordinary magnitude, was so completely suspended for a time, that 

 even the smallest and lightest pebbles were not moved or overturned. Had any of 

 them been turned over we should have found barnacles on the lower sides of them, or 

 perhaps on both sides ; nor did any current wash away the loose shelly layer that 

 afterwards covered the barnacle bed. The Balanus communis is a littoral species, and 

 Mr. Searles Wood informs me that he has generally met with it in the upper part of 

 the Red Crag. Professor E. Forbes, to whom I have shown the specimens, says that 

 the time required for such a growth of barnacles may have been three or four months, 

 and that they probably lived in very shallow water, if not between high- and low-water 

 marks. 



On the Scratched and Polished Rocks of Scotland. 



JBj/Sir Roderick I. Murchison, G.C.St.S., F.R.S., Pres. Geogr. Soc. 



The author first gave a brief sketch of the whole subject of abraded, polished and 

 striated rocks, to which for many years he had paid attention, by comparing the phae- 

 nomena in the British Isles with those seen in Scandinavia, Russia, the Alps, and 

 otiier })arts of the continent. He showed Iiow effects which had been exclusively 

 referred by Agasslz and others to the action of ice moving on land, or glaciers, could 

 now, in the vast majority of examples, be better accounted for by the agency of the 

 melting of snow and ice, the driving forward of ice-floes by powerful currents, and 

 the accompanying translation of vast quantities of drift composed of gravel, mud, 

 sand, and erratic blocks. 



Sir Roderick next described certain polished and striated rocks on the north shore 

 of Loch Fyne, wliich he had examined last summer in company with the Duke of 

 Argyll, particularly at the promontories of Kenmore and Penimore, where bosses of 

 tough, crystalline chlorite schist are powerfully abraded and rounded off wherever 

 they face to the E.N.E. or up the loch, and whose surfaces are rugged and natural 

 on the AV.S.W. or towards the sea. The portions of these rocks which have been so 

 mechanically ground down, exhibit also rudely parallel and slightly diverging lines of 

 striation, showing that they have been scored and fluted as if by the passage over 

 them of a heavy harrowing mass which had been translated from E.N.E. to W.S.W., 

 and the chief force of which had been expended on the faces of the rocks which stood 

 out as opposed to it. The author then referred to several other examples of 

 similar appearances in other parts of the seaboard of the West Highlands, particularly 

 on the sides of the lochs which open out from Ben Cruachan and Loch Etive to 

 Oban, the rounded and striated surfaces of the promontories and islets being invariably 

 presented towards the interior, and their jagged and rough faces towards the sea. He 

 also referred to his writings on the countless examples of precisely similar phseno- 

 mena in Sweden, in which flat country he had endeavoured to demonstrate, that 

 they never could have resulted from the action of terrestrial glaciers, and he now 

 applied the same reasoning to the lower parts of Scotland. 



Alluding to the lines of striation cited by Mr. Robert Chambers and other authors 

 as occiuring in the eastern counties north of Edinburgh, where the direction has been 

 from west to east, or nearly opposite to that mentioned on the west coast. Sir Roderick 

 then called special attention to a fact which in September 18.50 came under the notice 

 of Professor Nicol and himself near Glenluce in Galloway. There the sea-shore 

 trends from west to east, and the drift-marks are, as in the other cases, more or less 

 at right angles to it, being directed from north to south. In all these cases of 

 striation, gravel, stones, and shingle had been recently removed from the surface of 

 the rocks. From these data, which go to indicate that the drifted materials had in 

 all cases been derived from the chief adjacent masses of land, the author exjiressed 

 the opinion, that during the ' glacial epoch' Scotland probably consisted of a range of 

 rocky iiills in an icy sea, whicii by successive movements from different centres had 

 thrown off dislocated sheets of ice, with much melted snow and ice, forming a detrital 

 ' sludge' or drift which had been poured clown all the lateral openings. In Scotland, 

 therefore, as in Scandinavia, he accounted for the grinding down and striation of the 

 rocks in the lower gorges and on the lower grounds near the sea, by the passage of 

 such materials. At the same time he believes in the former existence in Scotland of 



