SCIENCE- GOSSIP. 



GEOLOGY 



CONDUCTED BY EDWARD A. MARTIN, F.G.S. 



A Primitive Ornament. — The little globular 

 hydrozoan which is so common in the Upper Chalk, 

 known as Porosphaera globularis (Millepora, Cos- 

 cinopora), was probably used as the earliest form 

 of ornament by our Palaeolithic ancestors. In as- 

 sociation with the implements that occur in the 

 High-Level Gravels of St. Acheul, near Amiens, large 

 numbers of these rounded bodies were found by 

 Prestwich, suggesting the idea that they had been 

 carefully collected from the chalk, and then strung 

 together, being perforated in such a way as to re- 

 semble beads. At the present time we see the 

 avidity with which the naked savage seizes upon 

 ornamental beads for the purpose of adorning his 

 person, and we seem to see, in this association of 

 these bodies with palaeoliths, the germ of that 

 artistic faculty which afterwards showed itself in 

 the etchings of deer and other animals that have 

 been found on slabs and antlers of the Cave 

 period. 



The Crag Deposits. — Mr. F. W. Harmer, F.G.S. , 

 read an important paper before the Geological 

 Society on May 9th on " The Crag of Essex, and 

 its relation to that of Suffolk and Norfolk." He 

 pointed out that the term "Red Crag," including, 

 as it does, beds differing considerably in age, is 

 vague, and, when we attempt to correlate the East 

 Anglian deposits with those of other countries, 

 inconvenient. It will be remembered that Prest- 

 wich divided the Coralline Crag into seven zones. 

 Mr. Harmer now divides the Red Crag, the Norwich 

 Crag, the Chillesford Beds, the Weybourn Crag, 

 and the Cromer Forest Bed series, into a series of 

 ten zones — that is to say, all the beds between the 

 Coralline Crag and the Arctic Freshwater Bed 

 (Clement Reid) of Suffolk. The line separating 

 the Older and Newer Pliocene is now drawn 

 by the author between the Lenham Beds, contain- 

 ing Area diluvii and other characteristic Miocene 

 species of the North Sea or of the Italian Pliocene, 

 and the Coralline Crag, the latter being considered 

 as the oldest member of a more or less con- 

 tinuous and closely connected series of Newer 

 Pliocene age. The palaeontological difference be- 

 tween the Coralline and Walton Crags is shown 

 to be less . than has hitherto been supposed. 

 The Norwich Crag occupies an area entirely distinct 

 from that of the Red Crag, no instance being known 

 where the one overlies the other in vertical section : 

 the fauna of the former is, moreover, more boreal 

 and comparatively poor in species. This crag 

 thickens rapidly towards the north and the east, 

 and is believed to form part of the great delta 

 formation of the Rhine. The mammalian remains 

 found at the base of the different horizons of the 

 crag in a remanie bed containing material derived 

 from various sources, are probably derivative from 

 deposits older than the Coralline Crag, formerly 

 existing to the south. The Chillesford (estuarine) 

 and Weybourn (marine) deposits — the latter charac- 



terised by the sudden appearance in the Crag basin 

 in prodigious abundance of TcHhin baltlticii — re- 

 present separate stages in the continued refigura- 

 tion of East Anglia during the Pliocene period; but 

 the Cromer Forest Bed (fresh-water and estuarine), 

 with its southern mammalia and its flora — similar 

 to that of Norfolk at the present day — clearly 

 indicates a return to more temperate condition-. 

 and must therefore be separated alike from the 

 Weybourn Crag on the one hand, and from the 

 Leda myalis sands and the Arctic Fresh-Water Bed 

 on the other. The two latter seem naturally to 

 group themselves together, and with the Glacial 

 deposits. 



The Gloppa Glacial Deposits. — About two 

 miles north-east of Oswestry is a small farm named 

 Gloppa. In the Glacial Gravels about there have 

 been found many species of shells. As these occur 

 at a height of 1,120 feet above sea -level, they 

 have been regarded, together with the shells at 

 similar heights at Moel Tryfaen (1,330 to 1,360) and 

 at Macclesfield (1,150), as evidence of the sub- 

 mergence of the land to these depths at the time 

 of deposition of the gravels. The gravels and sands 

 are said by Mr. A. C. Nicholson. F.G.S., to be 

 spread out around Gloppa, the main mass being 

 comprised in a ridge of eskers about 1,000 yards 

 long. About 60 feet of material were exposed at 

 Gloppa between 1888 and 1891. The gravel con- 

 sists of an agglomeration of erratics of many 

 kinds, Silurian grit and argillite, felsx^athic traps, 

 granites, etc., and bears a close resemblance to those 

 at Moel Tryfaen ; the larger ones being striated. 

 Although the bulk of the shells are in fairly good 

 condition, many are broken, rotted, and frag- 

 mentary. A portion of an elephant's tusk was 

 also discovered. The shells found include 

 some not now living in British seas, but proper 

 to Arctic and Scandinavian waters. Such are 

 Leda pernula, Astarte borealis, Dentalium abys- 

 sorum, JVatica affinis, Cardiwn groenlandiciuit, 

 Trophon clathratus, and others. The majority are 

 now living in British seas, and include Pecten 

 02)erciilaris, Mytilus edulis, PeetWteuliis gh/cimeris, 

 Cardiwn edule, Venus casino,, IAttorina littorea, 

 etc. Besides eighty-five living species, seventeen 

 derived fossils have been found, of Silurian, Car- 

 boniferous Limestone, Coal-Measure Sandstone, 

 Lias, Gault, and Chalk age. What are we to 

 think of such a deposit 1 What is the origin t if 

 this High-Level Glacial gravel ? Mr. Nicholson 

 doubted whether it could have been derived from 

 a Boulder Clay, the nearest deposit of this in the 

 neighbourhood being at a level of only 700 feet. 

 Whatever its origin, the remarkable state of pre- 

 servation of the shells appears to show that these 

 were contemporaneous in age with the deposit in 

 which found. Professor Hull thought that they 

 lived in a sea which contained rafts of ice or 

 small icebergs, and these deposited the boulders 

 amongst the beds of sand. As submergence of 

 the land took place, the molluscs would live at a 

 successively higher level up the sides of the sunken 

 mountains, whilst the ice-foot with derived Lias 

 and other fossils would also gradually mount, 

 until the fossils were left intermingled with the 

 remains of a contemporaneous fauna. The deposit 

 may indeed have been part of the great termi- 

 nal moraine of Professor Carvell-Lewis, which 

 accumulated where the melting of ice was in 

 progress, and which he drew across England, a] >- 

 proaching very near to this spot. 



