Revieios — Scharff's Origin of the European Fauna. 477 



the plants of the Forest-bed, Mr. Clement Reid tells us, are not 

 Arctic, and although the land and fresh- water molluscau fauna 

 remains much the same in the later deposits, the plants alone, 

 it appears, are quoted as indicators of temperature." (p. 492.) 



" It seems to me probable that the extensive migration of Alpine 

 and Arctic plants, which undoubtedly took place in past ages, 

 did occur long before the Glacial period, during a milder and 

 more equable epoch, and that they have since become adapted to 

 live in countries where they receive sufficient moisture during 

 summer, and are protected from severe frost in the winter by 

 a cover of snow. 



" I believe that neither the animals nor the plants which have 

 been discovered in British Pleistocene strata indicate the presence 

 of an Arctic climate in the British Islands during the so-called ' Ice 

 Age.' The theory of a general glaciation of these Islands — the 

 South of England excepted — has, however, been so universally 

 accepted by geologists, that it has almost passed the stage of con- 

 troversy, and is more generally regarded as an established fact. 

 I am not sure whether even those who are in favour of the view 

 of the marine origin of the Boulder-clay, disbelieve in a previous 

 general glaciation. Yet it is not long ago that the generally accepted 

 view was that all the phenomena now attributed to land-ice had been 

 produced by the action of floating icebergs. The rock-scorings, 

 ' crag and tail,' boulder-clay, scratched stones and drumlins, were 

 all believed to be due to the action of the sea, assisted by floating-ice. 



" I will not, however, venture to discuss this extremely intricate 

 subject of land-ice versus floating-ice ; and hope that geologists 

 may think fit to reconsider their final verdict in the light of the 

 conclusions I have arrived at from a study of the geographical 

 distribution of animals. 



" There is one factor of importance in connection with this theory 

 of an ice-sheet which may throw some light on the subject, and 

 that is, the configuration of Ireland during the Glacial period. 

 Mr. Close remarks : ' Some sufficient increase of relative height 

 towards the west or WSW., with a corresponding extension of the 

 land in that direction, is required, if we are to account for the 

 general glaciation of Ireland by the movements of a universal ice- 

 covering formed upon her own surface '; whilst Pi'ofessor Bonney 

 seems to think that the coast margin in the earlier part of the 

 Glacial period may have roughly corresponded with the present 

 hundred-fathom line. The land-connection between Scandinavia, 

 Scotland, and Ireland, formed, as we have seen, a highway for the 

 migration of the Arctic animals and plants. When the lowlands 

 of Ireland were covered by the sea, which event, I presume, 

 happened some time during the Glacial period, a broad belt of land 

 probably remained separating the Atlantic from this westward 

 extension of the Irish Sea." 



Suggested Marine Origin of tlie Boulder-clay. — " The Boulder-clay, 

 which covers such vast tracts of country in the British Islands and 

 the Continent, is now generally believed to be the ground-moraine 



