Reports and Proceedings — Oeol. Soc. London. 323 



not altogether, as may be seen from the description of the London 

 Model in the little " Guide to the Geology of London," published 

 by the Geological Survey. 



Each of the 24 sheets can be had separately, or the whole 

 mounted together on a roller, so that the map can be made available 

 for the pocket, the book-case, or the lecture-room. 



So far as we know there is no other case, but that of the late 

 Mr, Sanders' large map of Bristol, of the publication of a geological 

 map on so large a scale, as a private enterprise — such things are left 

 to Government Surveys — and therefore we trust that in the present 

 instance both publisher and compiler may be well rewarded. W. 



I^EZPOiaTS J^ISTJD I^JBOCIBIBIDIIsrG-S. 



Geological Society of London. — L — May 8, 1878. — Henry 

 Clifton Sorby, Esq., F.R.S., President, in the Chair. — The following 

 communications were read : — 



1. " On the Glacial Phenomena of the Long Island, or Outer 

 Hebrides." 2nd paper. By James Geikie, Esq., LL.D., F.R.S., F.G.S. 



In this paper the author gave some additional notes on the 

 glaciation of Lewis, and a detailed account of the glacial phe- 

 nomena of Harris and the other islands that form the southern 

 portion of the Outer Hebrides. Additional evidence was adduced to 

 show that Lewis had been glaciated from S.E., to N.W., and the 

 shelly boulder-clays and interglacial shell-beds of that part of the 

 Long Island were described in detail. Harris, North Uist, Benbecula, 

 South Uist, Barra, and the other islands that go to form the chain of 

 the " Long Island," were successively described under the headings 

 of Physical features, Geological structure, Glaciation, Till or Boulder- 

 clay, Erratics and perched blocks, Morainic debris and Moraines, 

 Freshwater lakes and Sea-lochs. Numerous bearings of stri», which 

 abound, were given, and these were held to prove that the whole 

 Outer Hebrides have been glaciated by ice that flowed outwards 

 from the mainland of Scotland. The position of abundant roches 

 moutonnees points to the same conclusion, and this is still further 

 supported by the " travel " of the Till. That deposit is generally 

 absent or very sparingly present on the rock-faces that look towards 

 the mainland, but it is heaped up in their rear, and spreads over the 

 lower tracts that slope gently towards the Atlantic. On the west 

 side of the islands not a few boulders occur in the Till which have 

 been derived from the east ; and the same is true of certain erratics 

 lying loose at the surface of the ground. The islands are well 

 glaciated up to a height of 1600 feet above the sea ; and the line of 

 demarcation between the glaciated and non-glaciated areas is 

 extremely pronounced. Above 1600 feet the hills show rugged, 

 splintered, jagged, and sometimes serrated tops. The author re- 

 garded the Till or boulder-clay as the morainic material that gathered 

 underneath the ice, and proof of this is given. Erratics and perched 

 blocks are very numerous, and most of these, as well as much of the 

 morainic debris, are believed to have been dropped where we now 



