552 R. Etheridge, Jun — Glacial De2oosits of Lewis. 



Down. Mr. Wm. Carruthers, F.R.S., placed at my disposal some 

 Scandinavian forms. Mr. John Ho2okinson, F.L.S., etc., forwarded 

 for comparison the forms collected by him in the Lower Ludlow 

 beds of Shropshire ; Mrs. W. Gray those of the Middle Silurians of 

 Girvan; and Mr. Jas. Henderson those of the Upper Silurians of 

 the Pentland Hills. 



IV. — Note on the Fossils from the Glacial Deposits of the 

 North- West Coast of the Island of Lewis, Outer Hebrides. 



By E. Etheridge, Jun., F.G.S. * 



IN a paper, read before the Geological Society of London (June 25, 

 1873), '' On the Glacial Phenomena of the Long Island or Outer 

 Hebrides,"! Mr. James Geikie mentioned the occurrence of two 

 descriptions of stony clay in the Long Island. The first of these 

 deposits or "Bottom Till" occupies the low ground of the island, 

 and is derived from the disintegration chiefly of gneissic rocks, and 

 so far as observation went proved to be unfossiliferous. The other 

 deposit was found in the north of Lewis, along the coast, and consists 

 of two beds of unstratified stony clay containing fragments of shells, 

 the lower resting on rock in situ. The beds in question also contain 

 numerous blunted stones and boulders, and are separated by inter- 

 mediate stratified beds containing shells and other fossils, usually in 

 a better state of preservation than those in either of the stony clays. 

 In his "Great Ice Age," Mr. Geikie describes^ these deposits more at 

 length, and gives the following general succession of the Glacial 

 deposits in Lewis, in descending order : — 



1. Boulder-clay. 



2. Sand, gravel, and coarse shingle, with rolled and angular fragments of shells. 



3. Dark bluish-brown clay and silt, with shells, many of them mere fragments. 



4. Boulder-clay, with broken shells. 



6. Tm. 



In 1874 Mr. Geikie paid another visit to Lewis, with the view of 

 further carrying out his observations on the glaciation of the island, 

 and during that visit I had the pleasure of accompanying him. The 

 following list gives the fossils obtained by us from the two localities 

 at which the fossiliferous beds had been noticed. It was our inten- 

 tion on starting to have devoted much more time to this branch of 

 the subject, but circumstances over which we had no control pre- 

 vented this, and we had to content ourselves with one short visit to 

 each of the localities. Could more time have been devoted to the 

 search, I feel sure the list would be considerably augmented, espe- 

 cially in the more minute organisms. Unfortunately we had no 

 appliances for bringing away with us portions of the sands and clays 

 for washing and sorting, all the smaller organisms having been ob- 

 tained by washing the matrix contained within the mollusca. 



The forthcoming new edition of Mr. Geikie's work renders it 

 unnecessary to say more on the geology of the subject, as that wiU 

 be fully treated of there. 



As before stated, two localities were hurriedly searched, viz. 

 1 Quart. Journ. Geol. Soc. vol. xxix. p. 532. ^ pp_ 209-11. 



