Yol. 54.] ON THE GLACIAL GEOLOGY OF SPITSBERGEN. 217 



The matrix is often contorted, and the fine beds are crushed and 

 l)ent as they pass round the huge boulders. This crushing and the 

 imperfect cleavage are, no doubt, due to subsequent earth-movements. 

 JBut the deposit is not a crush-breccia, and the boulders are foreign 

 to the locality. The general aspect of the deposit is strikingly like 

 that which a moraine would probably adopt if solidified, uptilted, 

 and subjected to extreme pressure. The age of the deposit is pro- 

 bably the same as that of the old glacial conglomerate on the 

 Yaranger Fiord described by Eeusch and Strahan. 



On the northern face of Bunting Blufi", in beds which are of late 

 Mesozoic or early Kainozoic age, one of us found another apparently 

 glacial deposit. It contained huge boulders of granite and other 

 rocks foreign to the locality ; some of these showed scratches which 

 are probably glacial in origin. 



At the mouth of Bell Sound, we found another case of the 

 occurrence of polished boulders scattered through a matrix of fine 

 materials. This bed is Lower Kainozoic ; but the boulders were all 

 well rounded, and they were never more than a foot in diameter. 

 The evidence in this case is less satisfactory, but the action of float- 

 ing ice would afford the most ready explanation of the characters 

 .of the deposit. 



YI. Some Geneeal Conclusions. 



In the preceding pages we have tried to limit ourselves to a simple 

 statement of facts, only classifying our observations and introducing 

 such theoretical suggestions as to justify their record. We now 

 propose to refer very briefly to the bearing of some of the facts on 

 the problems of glacial geology. 



(1) Land-ice versus Sea-ice. 



In view of the long controversy between the advocates of land- 

 •and floating ice, we sought for some test by which to distinguish 

 the action of these agents. But we could find no character by the 

 use of which it would be possible to decide whether a given deposit 

 had been formed by glaciers or by floating ice. Both forms of ice 

 round rocks, cut strise, and deposit heaps and ridges of contorted 

 and false-bedded material. The mere presence of marine shells is 

 useless, for they are transported and uplifted like any other material 

 with which a glacier has to deal. 



True boulder-paved terraces and shore-ridges can perhaps be 

 formed only by shore-ice ; but recognition of the latter would be im- 

 possible after denudation of the deposits had taken place ; and cases 

 have been described in wbich the action of a glacier on a moraine 

 crowded with boulders has formed a pavement closely resembling 

 those of the boulder-paved terraces.^ 



We found nothing being formed that would consolidate into a 

 good Boulder Clay like those of jSTorthern England except on land. 



1 W. Upliam, 'Irregularity of Distribution of the Englacial Drift,' Bull. Greol. 

 ^oc. Amer. vol. iii (1892) p. 136. 



