78 CHANGES OF CLIMATE DURING GEOLOGICAL PERIODS. 



boulders of granite and other rocks have been conveyed by the agency of 

 ice many miles from their natural source.* 



As far back as 1819 Dr. Buckland observed that on the Cotswold 

 Hills there were found pebbles of hard red chalk, which must have come 

 from the Wolds of Yorkshire and Lincolnshire ; and Mr. Lucy, who has 

 directed attention to the fact that these hills are sprinkled over with 

 boulders from Charnwood Forest, states that on visiting the latter placo 

 he found that many of the stones contained in it had come from Yorkshire. 



The inlets of the sea so common in Norway and there known as 

 fiords, and on the "West Coast of Scotland where they are called lochs, 

 are found only near mountains, and where thei'e are the unmistakable 

 evidences of glacial action, and in every instance the deepest part of 

 the loch is found to be at the head, and striae are observed in the rocks at 

 the sides often high above the sea level ; so that there is every reason to 

 believe that they, like the lakes of Switzerland, have been hollowed out 

 by the action of ice. A general consensus of evidence goes to prove that 

 at one time the whole of Scotland, with the exception of a few of the 

 highest peaks, wa3 locked in a great ice-sheet, coming down, in all 

 probability, from Scandinavia, and extending far out to sea, overspreading 

 all the islands, and connecting itself in one unbroken mass with the 

 almost equally extensive ice-sheet that covered Ireland. 



But not only is there this ample proof of the existence of a great 

 ice-age in Britain and other parts of Europe, and in North America, but 

 there is evidence, which though of necessity much scantier is yet 

 sufficient, of other glacial epochs long antecedent, with intermediate 

 warmer periods. Intercalated beds are found between the till or boulder 

 clay. In some cases from 20ft. to 30ft. of sand and gravel and peaty 

 matter, containing the remains of the elk, horse, reindeer, and mammoth, 

 have been found between layers of the till, and in some instances 

 four distinct formations of till have been found, separated from 

 each other by beds of sand from 2ft. to 20ft. in thickness. At the 

 last meeting of the British Association, paleolithic implements, pro- 

 nounced by Sir John Lubbock and others to be undoubtedly of human 

 origin, were exhibited, which were found beneath the chalky boulder clay 

 in various parts of East Anglia, proving the existence of man in these 

 districts previous to the glacial periods. In one case there was first 

 sandy soil 2ft., then chalky boulder clay 6ft., gravel 4ft., loamy clay 4ft., 

 boulder clay 6ft., chalk, and this spot yielded great numbers of flakes 

 and many implements. Other evidence of the existence of man in the 

 pre-glacial age is given in Heer's " Primeval World of Switzerland." 



The Forest Bed of Cromer furnishesevidence of distinct formations 



* Boulder Clay or Till.— This is a touch, clayey deposit, fine in texture, 

 tenacious, ami often of a stone-like hardness. It is always full of rocks and stones, 

 •which are usually covered with striae, otten crossing each other in various directions. 

 It is found chiefly in low lying districts, sometimes as much as 100 feet deep, -and, 

 occasionally it is found as high as 3,000 feet above the sea in hollows on hill sides. 

 The in,!, surfaces on which this rests are worn smooth, and when the rock is hard 

 greatly grooved and striated. The constituents of the till all correspond with th« 

 character of the rocks of the district. It is olien found underneath moraines, but 

 never above them. 



