Cole — Glacial Features in Spitsbergen. 205 



boulder-clay of the island, to settle down with the characteristic kettle- 

 hole structure (PI. XV., fig. 14, and PL XII., fig. 7). Escaping streams 

 have here and there washed the clay, leaving " glacial sands and gravels " as a 

 residue. The limit reached by the ice on the low limestone surface of the 

 island is marked by a distinct margin to the boulder- clay, and along this a 

 stream runs, with pebbles in its floor (PI. XVI., fig. 15). The clay itself has 

 weathered like that of the von Post Glacier, and presents steep faces on its 

 hummocky surface. In the Dublin district, the fragmental condition of the 

 shells has always been appealed to as showing that they could not have 

 originated in place. Yet here, on Cora Ireland, we have convincing evidence 

 that a loose marine deposit may be moved forward, perhaps in a frozen state, with 

 very little injury to the included shells. These shells include i\lya truncata, 

 Fecten islmidicus, Saxicava ardica, Mytilus edulis, Astarte borcalis, Tellina 

 calcarea, and, more rarely, Mya malis, Modiola mytiloides, and Yoldia ardica. 

 A few gastropods, mainly Buccinum, also occur. Perfect specimens of these 

 shells abound, and hundreds of the bivalve molluscs may be collected in 

 which the valves remain in their natural positions in regard to one another, 

 even though the shell has gaped and become filled with clay. Lithothamnium 

 forms a large portion of the deposit, just as it does in the post-glacial raised 

 beaches, which rise to some 350 feet above the sea on the margins of the Ice 

 Fjord. In the moraine of Cora Island, the colouring of the shells is 

 excellently preserved ; but this is also true of many of the raised beaches of 

 the Ice Fjord. 



Fluvio-glacial Deposits. 



In all cases in the Ice Fjord in Spitsbergen where glaciers have retreated 

 up their valleys, the deposits of the rivers that flow copiously from them form 

 a stony alluvium, and in places large deltas extend over the raised beaches 

 and out into the sea. A well-developed delta, with hooks and islets, thus 

 forms the flat land at Cape Wijk in Dickson Bay. There is much to justify 

 the view that extensive fluvio-glacial deposits may be forming at one point, 

 while glacial advance is taking place at another, and that such deposits afford 

 no clue as to general climatic conditions in the past (PI. XVI., fig. 16). 



Many of the stones in these deposits remain very angidar, much as they 

 have fallen from the ice or from the mountain side. The rivers that flow 

 from the glaciers have occasionally cut ravines in the rock -floor since the 

 retreat of the ice. A notable feature of this kind, accompanied by an 

 older outlet-channel, which is now abandoned, occurs on the west shore of 

 Green Bay. 



