162 



HARDWICKE'S SCIENCE-GOSSIP. 



catkins I explain, partly on the principle of corre- 

 lative growth, and partly by the slight encouragement 

 it receives by the visits of the bee. — J. Ilamson, 

 Bedford, 



GEOLOGY. 



" The Age of the newer Gneissic Rocks of 

 the Northern Highlands." — Whilst Professor 

 Geikie has been endeavouring to demolish the Archean 

 rocks of Wales, other geologists have been finding 

 Archean rocks in Scotland, and have thus succeeded 

 in carrying the war into the enemies' camp. A paper 

 on the above subject has just been read before the 

 Geological Society, by Mr. C. Callaway, D.Sc, F.G.S. 

 The object of the author was to prove that the 

 eastern gneiss of the Northern Highlands, usually 

 regarded as of "Lower Silurian" age, was to be 

 placed in the Archrean. While admitting that this 

 gneiss frequently overlies the quartzo-dolomitic group 

 of Erriboll and Assynt, he held that this relation was 

 due to dislocation accompanied by powerful thrust 

 from the east, which had squeezed both formations 

 into a series of folds, thrown over toward the west, 

 so as to cause a general easterly dip. 



The Carson Footprints. — Professor Leconte, a 

 well-known American geologist and naturalist, has 

 been personally examining these footprints for 

 several days, and he writes to " Nature," stating that 

 the conclusion he has arrived at is that the tracks 

 are not human at all, but were most probably made 

 by a gigantic ground sloth, such as the Mylodon, the 

 remains of a species allied to which were found in 

 the Upper Tertiary Strata of Nevada. 



."The great Ice Age." — At a recent meeting 

 of the Royal Society, Professor James Geikie said that 

 the limits were indicated of the Great Scandinavian 

 ice-sheet which pushed itself southward over north 

 Germany and over the watershed of Central Russia, 

 and westward across the German Ocean towards 

 our islands, thereby modifying the trend of the native 

 ice-streams that have left their traces all over our 

 hills and round our coasts. As an indication of the 

 great power of this agent it was mentioned that some 

 portions of the brown coal beds of Saxony which 

 have been long worked are really not in situ, but 

 have been pushed out of place by the ice-sheet. In 

 describing the fluviatile deposits, Professor Geikie 

 drew attention to a suggestion made by Darwin, that 

 frozen snow accumulating in the valleys below the 

 glacier limits might easily act as barriers and give 

 rise to extensive flooding. 



The Liverpool Geological Society.— Part 4 of 

 Vol. iv. of the Proceedings of this, one of the oldest 

 •established of our provincial Geological Societies, 



is to hand, containing the following papers : — 

 "Traces of an Interglacial Land Surface at Crewe," 

 by D. Mackintosh, F.G.S. ; " Marine and Peat beds 

 of Formby and Leasowe, recently disclosed by the 

 cutting for the outersewer at Ilightown," by T. M. 

 Reade, F.G.S. ; "Mammalian Remains from ditto," 

 by F. G. Moore : " Subsidence of Land in the Salt 

 Districts of Cheshire," by Thomas Ward ; " The 

 Carboniferous Limestone and Cefn-y-Fedw Sand- 

 stone of Flintshire," by G. H. Morton, F.G.S. ; " The 

 base of the new red sandstone in the country around 

 Liverpool," by G. II. Morton, F.G.S., &c. 



The Estuaries of the Severn and its 

 Tributaries. — Professor Sollas read a paper before 

 the Geological Society on June 6th on this subject. 

 Various sources have been ascribed to the mud 

 which is so characteristic of the estuaries of the 

 Severn and its tributaries, such as the rivers them- 

 selves, the waste of mud shoals, or of bordering 

 cliffs, or the sea. The author considered the effect 

 of these sources of supply, and showed that, although 

 the first three are doubtless to a certain extent 

 correct, they are inadequate to account for some very 

 important phenomena. The tidal silt, on micro- 

 scopic examination, is found to consist of both 

 inorganic and organic materials, the former being 

 argillaceous granules, grains of quartz, flint, &c. ; 

 the latter, coccoliths, coccospheres, Foraminifera, 

 occasional sclerites of Alcyonaria, fragments of 

 Echinodermata, and triradiate spicules of Calci- 

 spongia, together with numerous spicules of siliceous 

 sponges, a few Radiolaria and a variable quantity of 

 Diatoms. These organisms (described in detail by 

 the author) are marine, and yet they occur on the 

 banks of rivers at a great distance from a truly 

 marine area. The author showed it to be improbable 

 that they can have been derived, at any rate to a 

 considerable extent, either from the older formations 

 through which the Severn flows, or from the alluvial 

 flats of its estuary ; for although the latter do contain 

 marine organisms of a generally like kind, the spicules, 

 &c, indicate corrosion, and are generally not so well 

 preserved as those which occur in the tidal silt. It 

 seems therefore necessary to conclude that a con- 

 siderable proportion of the organisms now present 

 in this have been brought from the sea ; but sponges 

 are not known to grow in any quantity nearer Bristol 

 than the coasts of Devon and Pembrokeshire. It 

 would therefore appear that these organisms, contrary 

 to what might have been expected, have beeu drifted 

 up into the tidal estuaries of the river for a very 

 considerable distance. The author concluded by 

 describing in detail the alluvial tracts of the Severn, 

 which he considers to have been formed (with certain 

 differences of level) much as tidal deposits are formed 

 at the present day ; and by pointing out the bearing of 

 his investigations on the question of the probable results 

 of the discharge of sewage into tidal rivers. In the 



