194 DISCUSSIONS IN CLIMATOLOGY. 



year by year, how few of them have the good fortune 

 to discover a single relic. In fact a geologist might 

 search for months, and yet fail to meet with an inter- 

 glacial deposit. The reason is obvious. The last ice- 

 sheet, under which Scotland was buried, was so 

 enormous as to remove every remnant of the preceding 

 interglacial land-surface, except here and there in deep 

 and sheltered hollows, or in spots where it may happen 

 to have been protected from the grinding power of the 

 ice by projecting rocks. But all those places are now 

 so completely covered with boulder-clay and other 

 deposits that it is only in the sinking of pits, quarries, 

 in railway-cuttings, and other deep excavations that 

 traces of them accidentally turn up. Now if it is so 

 difficult to find in temperate regions, in a place like 

 Scotland, interglacial remains, how much more difficult 

 must it be to meet with them in Arctic regions where 

 the destructive power of the ice must have been so 

 much greater. 



Something like indications of an interglacial period 

 appear to have been found by Professor Nordenskjold 

 in Spitzbergen. " In the interior of Ice-fjord," he says, 

 "and at several other places on the coast of Spitz- 

 bergen, one meets with indications either that the 

 polar tracts were less completely covered with ice 

 during the glacial era than is usually supposed, or 

 that, in conformity with what has been observed in 

 Switzerland, interglacial periods have also occurred in 

 the polar regions. In some sandbeds not very much 

 raised above the level of the sea, one may, in fact, find 

 the large shells of a mussel (Mytilus edulis) still living 

 in the waters encircling the Scandinavian coast. It is 

 now no longer found in the sea around Spitzbergen, 

 having been probably routed out by the ice-masses 



