INTERGLACIAL EPOCHS. 291 



Scotland, interglacial deposits that range in thickness from a 

 foot or two up to twenty yards and more, where is the improba- 

 bility of its having overridden much thicker and more continuous 

 deposits in those low-lying parts of England and the Continent 

 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 submergence 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 

 firths (which are merely submerged valleys) — that we find the 

 relics of the marine stage of the last interglacial epoch attain- 

 ing any extent. A good 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- section, however, they show little 

 or no disturbance at all, but the till rests upon 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, 



