76 Dr. James Geikie — Preservation of Bejjosiis under ' Till.' 



glaciated Scotland, are not equally crumpled and contorted. Oc- 

 casionally the layers of sand and laminated clay lie quite horizontal, 

 ■ even when the Till cuts down, as it were, to the depth of 20 feet 

 and more into the stratified deposits. We have, therefore, further 

 proof that ice may roll its bottom-moraine over incoherent deposits 

 without disturbing the horizontality of their bedding, although at 

 the same time these same deposits may here and there be abruptly 

 cut out and truncated. 



If such has taken place in the valleys of a well-glaciated counti-y 

 like Scotland, it surely cannot be unreasonable to infer that in a less 

 ice-worn country, in a region where the ice was not so thick, and 

 where its motion was slower, interglacial beds should be much 

 better preserved. If the ice has spared, in hilly Scotland, inter- 

 glacial deposits that range in thickness from a foot or two up to 

 twenty yards and more, where is the improbability of its having 

 overridden much thicker and more continuous deposits in those 

 low-lying parts of England where it approached its termination ? 



And here I may remind geologists of one among many equally 

 suggestive facts, connected with the distribution of interglacial beds 

 in Scotland, that while we have indubitable evidence of a sub- 

 mergence of the land, during the last interglacial period, to an 

 extent of upwards of 500 feet, the marine deposits of that date have 

 yet been all but entirely swept away from the higher levels and 

 more exposed parts of the country — there being only one place 

 where they are met with so high up as 500 feet. It is not until we 

 get down to the low country — to the wide open valleys, and to the 

 borders of some of the great friths (which are merely submerged 

 valleys) — that we find the relics of the marine stage of the last 

 interglacial period coming on in force. An excellent example of 

 this peculiar distribution of interglacial marine deposits came before 

 me recently in the Outer Hebrides. Interglacial beds are met with 

 in two places in the Long Island, namely, at Ness and in the Eye 

 Peninsula. The highest point attained by these deposits is about 

 200 feet above the sea. They rest upon an eroded surface of Till, 

 and are themselves overlaid by a second or upper Till, underneath 

 which they show a most irregular surface, as a rule, being cut into 

 by the Till and crumpled, contorted, and confused. In other parts 

 of the same cliff-sections, however, they show little or no dis- 

 turbance at all, but the Till rests i;pon them apparently quite 

 conformably. In the Eye Peninsula they occur as a mere local 

 patch, which exhibits all the appearance of having been scooped and 

 ploughed out — the clay being abruptly truncated, and overlaid by 

 red Till. When these interglacial beds were accumulated, all the 

 low grounds of Lewis, up to a height of 200 feet at least, must 

 have been submerged — and this submergence could hardly have 

 been local and confined to Lewis, but extended in all probability to 

 the whole Outer Hebrides. Where, then, we may well ask, are the 

 marine deposits which must at one time have cloaked these low 

 grounds — where are the olay-beds and sandy deposits and beach 

 accumulations which must have been laid down contemporaneously 



