538 REV. R. B. WATSON ON THK GREAT DRIFT-BEDS WITH SHELLS 



wards, ever by the steepest and the fastest descent it could find, towards the 

 valleys and the sea. At the shore the ice-cake would still sink, crushing down, 

 and yet partly resting on, the debris which lay beneath it, until at a depth pro- 

 portioned to its thickness it would at last be floated up, forming that flat terrace 

 along the land known among Arctic travellers as the ice-foot. Beyond t he 

 ice-foot, we know what occurs in Greenland, and some of the main features are 

 familiar even to Norwegian travellers : floating icebergs, laden with debris, 

 driven about by winds and currents, — masses of ice floating up with a thaw, and 

 bringing up rocks to which they had been frozen, often dropping these again at a 

 far higher level than their parent bed, — turbid fresh water, ice cold, flowing out 

 to sea in a shallow stream, destructive of all animal and vegetable life. At the 

 edge of the ice-foot, a steep bank of tumultuous debris,* shelving down precipi- 

 tously to a great depth ; beyond this, gravel, sand, and mud irregularly distri- 

 buted, according to the currents, but in the main a fine mud always present at a 

 distance ; seaweeds rare, or only locally frequent ; while, from the very edge of 

 the debris bank, animal life in abundance, but in the tumult of the debris bank 

 itself only exceptionally present. Such are the phenomena more or less to be 

 found along all glacial coasts; and such, no doubt, were the phenomena of our 

 own shores in the glacial period. 



This then being so, we are entitled to say— 



1. That the material of the boulder-clay is the result of land glaciation. The 

 enormous debris torn from the abraded surface of the basement rock must have 

 gone somewhere — the huge boulder-clay heaps must have come from somewhere. 

 Do not the two fit each other, as the broken masses of a land- slip in the valley fit 

 the bald rock-face on the hill above ? 



But besides this, the shells associated with the boulder-clay are decidedly 

 boreal in character, and indicate just such a glacial climate as the ice-covered 

 land implies. The shells, therefore, show that the boulder-clay in which they are 

 found belongs to the glacial period. 



2. The ice covered the land till it was submerged. This certainly implies a 

 great severity of cold, and an enormous snow-fall, and yet this seems actually to 

 have been the case. Had it been otherwise ; had the ice- cake begun to Avaste 

 off the land at the lower levels before these were covered by the sea, we should 

 probably have found traces immediately on the rock of the debris with which a 

 glacier is charged, and which, in melting, it would have left behind it. The ice 



* I have repeatedly lain on the edge of such a bank, at the mouth of glacier rivers in Norway 

 — particularly at the Skars Fjord glacier, where nothing but warps would hold us, tlie face of the 

 bank on which our anchor lay being too steep to afford any hold. Our bows were almost grat- 

 ing on the shingle, while we had 70 fathoms under our stern, and 83 fathoms, with a fine mud 

 bottom, at 100 yards distance. The surface water was filthily turbid, bitterly cold, perfectly fresh, 

 and not above 8 or 9 feet deep, if so much ; below was the clear salt water, sensibly warmer, and 

 swarmine: with animal life, both fish and mollusks. 



