RECENT LITERATURE. 55 



It is usually admitted that in the earlier periods of the Tertiary 

 Epoch — the epoch in which we are now actually living, though it was 

 formerly the fashion to isolate ourselves in a "Quaternary Epoch " — 

 the climate and configuration of Western Europe were very different 

 to their present condition. The former was semi-tropical, while the 

 Continent had a ijotable extension westwards, there being solid laud, 

 broadly speaking, from North Scandinavia to Spain, including the 

 Britisli Isles. Till recently it was very generally held that a " Glacial 

 Period" or "Ice Age" ensued, which was of such a rigorous nature 

 that all life was blotted out over almost the whole of Europe. This is 

 the view held, for instance, by Buchanan White,''' E. Hofman.f and 

 W. Petersen.]: E. F. Scharff, on the contrary, § maintains an almost 

 diametrically opposite view, the crux of his position being "that the 

 glacial period in Europe was not a time of extreme cold, and that its 

 destructive effect on the animals and plants was by no means such as 

 is currently reported"; in fact, that the climate was not very different 

 from what obtains now, but moister, with warmer winters and cooler 

 summers. Scharff has been criticized at great length by L. Stejueger,|| 

 who holds an intermediate position, and considers that the Ice Age in 

 Europe was similar in climate to that now obtaining in Greenland and 

 the islands north of Hudson's Bay.H It is therefore obvious that the 

 presence or absence, at the present day, of " pre-glacial " faunas in the 

 British Islands, and in Ireland especially, is far from being an esta- 

 blished fact. Buchanan White considered that Britain derived the 

 whole of " its butterfly fauna from Continental Europe in post-glacial 

 times," a natural sequence to his belief of the rigour of the glacial 

 climate. It is remarkable, however, that at the commencement of the 

 Ice Age a large portion of the western continent was submerged, and 

 Ireland was cut off from Spain, but was nevertheless prolonged south- 

 wards considerably beyond its present limits. It is considered possible 

 that this south-western extension — now submerged — was the refuge of 

 the pre-glacial semi-tropical British " Biota " (as Stejneger terms the 

 "Fauna" and " Flora"). The presence in Ireland of such forms as 

 the spotted slug [Geomalacus macHlosiis), and the strawberry-tree (^Jriuius 

 unedo), can scarcely be otherwise explained, although Kane seems to 

 favour a post-glacial bridge between South Ireland and the west coast 

 of France. It is doubtful, however, whether any Insects can be 

 pointed out with any degree of certainty as pre-glacial relics, and there 

 is always the risk of confounding these with comparatively recent im- 

 portations due to the formerly not inconsiderable commerce between 

 the Peninsula and Ireland. Among these "relics" may possibly be 

 the little moth Zelleria philli/rella, a native of Southern France, Italy, 



■'' "Some thoughts on the distribution of the British Butterflies," 1881, 

 'Entomologist,' xiv. pp. 265-77. 



t " Die Isoporien der Europ. Tagfalter," 1873, Inaugural Dissert. Philos. 

 Fakultat, Jena. 



I "Die Lepidopt. Fauna d. arktisch. Gebiete v. Euroi3a," 1888, Beitr. 

 Kenntn. Euss. Eeichs iv. 



§ ' History of the European Fauna,' London, 1899, vii and 364 pp., 21 figs. 



II Scharff' s " History of the Europ. Fauna," 1901, American Nat. xxxv. 

 p. 87, et seqq. 



•f In connection with this Stejneger notes that a humming-bird occm's as 

 far North as Sitka, almost within sight of the gigantic glaciers* 



