HAllDWICKE'S SCIENCE-GOSSIP. 



or 



GEOLOGY. 



EossiL HvDrvOzoA. — The liydrozoa are the rarest 

 group of orgauisiiis which have yet been met with, 

 as, with the exception of the doubtful Oldhamia, 

 the well-kuown characteristic fossil of the Cambrian 

 rocks, only the impression of a Medusa has been 

 discovered in the Solcnhofcu stone. To these Mr. 

 James Thomson, E.G.S., of Glasgow, has added a 

 nevr genus and two new species, from the car- 

 boniferous shales of the West of Scotland. The 

 generic name of Palccocoryiie has been given to the 

 former, and Scoticum and radiatmi to the latter. The 

 nearest related group is the anomalous Bimeria. 



Carbonipekotjs Reptiles. — Professor Cope 

 has recently given a detailed account of the car- 

 boniferous reptiles of Ohio, U. S. They are re- 

 ferable to ten genera, and include twenty-seven 

 species. These reptiles are of tlie most interesting 

 character, on account of their forming so many 

 "missing links." Most of them are batrachians, 

 but one {Jilolgophis) resembles the serpents, with 

 certain peculiarities of structure. 



The Latest Changes in the Nouthern 

 HEMispnErxE. — It was after the emergence of 

 Europe from the glacial sea that floral migrations 

 began more particularly to spread over her. The 

 climate was still rigorous in its character, the 

 snow-line coming down in the wiuter probably to 

 near the sea-level, as it now does in Greenlaud. 

 Over the available area, arctic plants spread them- 

 selves, finding luxuriant habitats in the newly- 

 formed subsoils of the "Drift." The hairy mam- 

 moth, woolly-haired rhinoceros, the Irish elk, musk 

 ox, reiudeer, glutton, lemming, &c., more or less 

 accompanied this flora, and their remains are 

 always found in the great glacial deposits of Europe 

 as low dow^n as the South of France. In the 

 New World, beds of the same age contain similar- 

 remains, indicating that they came from a commo7i 

 northern centre, and were spread over both con- 

 tinents alike. WHien the animals and plants of the 

 Arctic and sub-Arctic regions of the Old and New 

 worlds are compared, one cannot but be surprised 

 at their identity. All, or nearly all, belong to the 

 same genera, whilst many of the species even are 

 common to the two great continents. This is most 

 important in its bearing on our theory, as indi- 

 cating that they radiated from a common centre 

 after the Glacial period. W^hen we explore the 

 temperate regions of the same countries, we find 

 the floral and faunal difterences increasing, as one 

 would expect iu remembering that many of the 

 species date from the Jliocene epoch. In equatorial 

 latitudes this contrast reaches i(s climax. No 

 other theory will explain this peculiarity than that 

 Arctic and sub-Arctic species have spread since the 

 (tlacial epoch, whereas the southern and equatorial 



forms are older geographically, and were driven to 

 their present areas of occupation by the slowly but 

 surely advancing cold of the period in question. — 

 /. 2?. Taylor, on tlie " Geographical Distribution of 

 Animals and Plants," in " Westminster Review." 



Elint Elakes. — I had no opportunity of 

 reading Mr. Whitley's letter on Elint Flakes in 

 your number for August last till the close of 

 the year. I can fully confirm Mr. Whitley's 

 statements respecting the flint flakes from his 

 " crusher," of which I have several, not to be dis- 

 tiugui.shed in form from what are considered to be 

 typical prehistoric specimens; but these crushed 

 flakes are wanting ia one particular, viz., the 

 patina, or white crust, the effect of long exposure 

 to atmospheric influence ; and it is by these quali- 

 ties of form and colour that " we learn to distin- 

 guish between false and true weapons." I feel 

 pretty sure I am not wrong in ascribing great 

 importance to the "patina" as a test of the au- 

 thenticity of flint flakes, for in and around Paris 

 they are, almost without an exception, found only 

 on a level with the river in all the gravel-pits with 

 which Paris abounds. There, and there only, are 

 they met with ; and this is so universally the case, 

 that although I have searched almost every gravel -pit 

 that was open last year round Pai'is and St. Germains, 

 I only met with one flake at a higher level, and 

 M. de Mortillet pointed to a rust-stain on its 

 surface in proof that it had come from the surface 

 gravel, and had been struck by the spade or 

 some iron tool. Now this level is exactly that 

 where the bones of extinct animals are found, 

 and corresponds with the levels at Amiens and 

 Abbeville, at which flint flakes have been found 

 mingled with the bones of the same animals, 

 and even with those of man ; yet neither Amiens 

 nor Abbeville is on the Seine. In the South of 

 France also human bones, as well as flint flakes, 

 have been met wi-Ii at the same levels in river 

 gravel. Neolithic or worked flints have almost 

 as invariably been found at a higher level ; and 

 the patina, when it exists is not so thick as on 

 the flakes. M. de Mortillet assures me that flint 

 flakes taken from peat bogs, bottoms of rivers, and 

 other places to ^ hich air has no access, have no 

 patina. The downs here are covered with millions 

 of flints, both whole and broken, yet in ten minutes 

 I found more characteristically- shaped flakes from 

 Mr. Whitley's crusher than I could find in ten 

 hours upon the downs. And why ? Because nature 

 splits them by frost and heat, which do not give 

 them regular edges and facets, while the crusher 

 acts as primeval man did, and splits them by force 

 applied ab extra, the effect of which is the same, 

 whether it be a crushing power or a blow from 

 another flint, man's sole weapon at that period. — 

 T. Ogin Ward, M.I)., Oxon. 



