NA TURE 



[December 26, 1907 



cultural Education Association " for the purpose of test- 

 ing the relationship of the {geological boundaries and the 

 soils." On p. no the pala2onlologists report in favour of 

 the view that the rugose corals were primarily hexamerous, 

 a question still under discussion, as may be seen from a 

 note in Nature, vol. Ixxvi., p. 117. The original papers 

 in the appendix, corresponding to the well-known Bulletins 

 of the Geological Survey of the United States, include 

 one by Dr. Flett on the scapolite-bearing rocks of Scot- 

 land, and- a valuable summary by Mr. U. A. Macalister 

 of the quantity of tin, copper, and other minerals pro- 

 duced in Cornwall. 



The " solid " and " drift " maps, Nos. 230 and 247, 

 are issued simultaneously with the memoirs describing 

 them, under the care of Dr. Aubrey Strahan, and cover 

 parts of the great South Wales coalfield (1907, memoirs, 

 price 2.S. 6d. each ; maps, is. bd. each). The former 

 memoir deals with the country round Ammanford, north 

 of Swansea, where the Silurian strata, through the Lud- 

 low Tilestones, pass up into the Red Marls that form the 

 base of the Old Red Sandstone. The usual unconformity 

 of the latter on a Caledonian land-surface is revealed, how- 

 ever, by the fact that it oversteps every member of the 

 Silurian system (p. 53), until it rests directly on the Arenig 

 rocks in the extreme north-west of the map. The details 

 shown on these modern maps necessitate a good deal of 

 freedom in the use of colours, and blues and greens and 

 yellows are used for lithological divisions (which are, of 

 course, supported by palasontology) in a way that would 

 hardly commend itself to the soul of William Smith. 

 Would not a variety of linings and stipplings in the same 

 colour, which produce all the effect of separate tints, serve 

 on such colour-printed maps for minor subdivisions of our 

 British systems? The American and New Zealand surveys 

 often provide us with examples. 



\\'e note (p. 37 of Memoir No. 230) that " Ordovician " 

 now officially replaces the " Lower Silurian " of the older 

 survey; but is it wise to restrict "Silurian," in the face 

 of almost all the geological world, to the former " Upper 

 Silurian" alone? Prof. De Lapparent in 1893 at any 

 rate showed us a clear way out of the difificuUy. 



Memoir No. 247 includes the busy town of Swansea, and 

 the map brings us to the southern edge of the great coal- 

 field. Mr. E. E. L. Dixon (pp. 11-20) furnishes an 

 interesting account of the dolomitisation of the limestone 

 soon after its deposition in the Carboniferous sea, and the 

 plates and descriptions ought to be useful to workers in 

 many other districts. The growing difficulty in drawing 

 a line between the Lower and Upper Carboniferous series 

 in Britain is well seen by the remarks on pp. 28-29. '^''• 

 Tiddeman (p. 121) has traced a pre-Glacial raised beach 

 from Mumbles Head westward, the fauna of which shows 

 that the whole Cainozoic Glacial epoch was an episode of 

 our own times, if we take the mollusca as our guide. It is 

 now urged (p. 127) that Rhinoceros, Elephas, Bos, and 

 Cervus, found in the Gower Caves, lived here before the 

 arrival of the ice, since raised beach deposits admittedly 

 appear in the cavern-floors. The subsidence that was 

 shown at the Barry Docks in Cardiff to be later than 

 Neolithic times has carried peat in the Swansea area 

 (p. 145) to a level of 44 feet below high water. 



The memoir on the geology of Islay has also appeared 

 fi907, price 2S. 6d.). The author, Mr. S. B. Wilkinson, 

 is referred to in other memoirs as Mr. B. S. N. Wilkinson, 

 a point of which bibliographers should take notice. The 

 maps here described were issued some years ago, and 

 cover a little visited and very attractive district. The 

 ordinary pedestrian in Jura and Islay will find much 

 romantic ground, and may still travel bv introduction from 

 one farm to another, in the good old highland style. The 

 present writer well remembers how he was waylaid by an 

 old peasant woman early one morning on the Jura path- 

 way, and forced to accept a parcel of oatcake, lest he 

 should weary before reaching the ferry at the north end 

 of the island. 



Mr. Wilkinson enables us, in his first chapter, to realise 

 the main features of Islay, and he rightly directs atten- 

 tion to the extreme brilliance of the colouring on sunlit 

 days along the coast. The rocks include much crushed 

 and mylonitic Lewisian gneiss ; sediments regarded as 

 Torridonian ; phyllites, limestones, and quartzites, corre- 

 NO. T991, VOL. 77] 



lated with the Central Highland series ; and, resting on 

 these with a slight unconformity (p. 44), a series in which 

 dolomite is prevalent. A considerable thrust-plane 

 separates the quartzitc and conglomerate of this series in 

 the north of the island from the rocks referred to the 

 I Torridonian. Drs. Tcall and B. N. Peach have made 

 I important contributions to this memoir. It is illustrated 

 by photographic plates of exceptional beauty. It was un- 

 necessary, however, to supply Plate ii. in our copy in the 

 condition of a " proof before letters." 



In the Verhandlungen der k.k. geologischen Rcichs- 

 anstalt for 1907, Herr Vacek (p. 159) continues the con- 

 troversy with Herr Heritsch on the basin of Graz, and 

 we are led to understand that the junior author, whose 

 youth is greatly insisted on, may now be carried off the 

 field. He is sagely advised not to quote authorities, but 

 to become one himself. Surely we have heard something 

 of this kind in geological exhortations nearer home. 



Herr Ampferer (p. 192), in his usual systematic style, 

 gives a reading of the structure of the Rhatikon range 

 on the Swiss and Austrian frontier, in which he shows 

 that he is not fascinated by what Schardt has called 

 " Ultranappismus." Ampferer goes so far as to suggest 

 that certain foreign blocks amid Tithonian limestone, re- 

 garded by von Seidlitz as evidence of a " Fenster," and 

 thus connected with overfolding, have been brought into 

 their present position by ice which overrode the chain. 



The Jahrbuch of the same institute for 1907 contains 

 many descriptive papers, from von Troll's study of the 

 Pontic fauna in the basin of Vienna (p. 33) to Schubert's 

 work on the north Dalmatian coast (p. 1). Dr. Schubert 

 incidentally opposes the suggestion, made from a study of 

 old maps, that extensive geographical changes have 

 occurred in the Adriatic isles within historic times. 



Dr. Hinterlechner (pp. 115-374) contributes an important 

 memoir on the sheet of the map round Deutschbrod 

 (Nemecky Brod, the German ford), in eastern Bohemia. 

 .•\ broad plateau of gneiss and granite here unites Bohemia 

 and Moravia ; the traveller may find it monotonous, but 

 for the fantastic architecture of its towns. Dr. Hinter- 

 lechner shows what problems of metamorphism lie beneath 

 its undulating fields and little woods. He urges (p. 332) 

 that the great mass of the cordierite and biotite gneisses 

 result from the contact-alteration of a sedimentary series, 

 which has been left intact in one particular zone. Rocks 

 once regarded as .Archaean are shown to be intrusive in 

 this sedimentary envelope (p. 351), the age of which re- 

 mains uncertain. Here again we note the striking 

 change of opinion forced on observers in many lands 

 when careful field-investigation comes to be carried on. 

 Almost all our recent researches lead us farther away from 

 the supposed Archaean crust of purely igneous origin. 



Walery Ritter von Lozinski describes in the same journal 

 (P- 37S) tl^s glacial deposits and loss of northern Galicia, 

 and traces the ice-tongues of the epoch of maximum 

 glaciation into the northern valleys of the central 

 Carpathian range. He finds (p. 395) that the thin mar- 

 ginal ice of the great continental sheet moved to a con- 

 siderable height up gentle slopes, but was unable to climb 

 steeper hillsides. Unglaciated areas therefore appear, say 

 250 metres above the sea, side by side with others invaded 

 by ice to a height of 300 metres. 



Among palaeontological papers may be cited a iong 

 memoir by Dr. A. Till on the jaws of fossil cephalopods 

 (ibid., pp. 535-682), an outcome of his previous studies 

 on the examples found in the Neoromian [ibid., iqo6, 

 p. 89). Four new genera are proposed, and the jaws 

 belonging to Nautilus are marked off clearly from all 

 others (p. 658). The latter types diminish rapidly at the 

 close of Lower Cretaceous time, and the author (p. 680), 

 in consequence, suggests that thev were connected with 

 the Belemnoldea. Throughout both the memoirs referred 

 to. Dr. Till writes " Rhynchotheutis " and " Palaeo- 

 theutis " consistently ; but surely this is a curious error in 

 one who is so much a specialist. 



The Bulletins de la Commission g^ologiquc de Finlande 

 are always of interest. In No. 23 (June, 1007) Mr. Sederholm 

 writes, with an English summary, on " granite and gneiss, 

 their origin, relations, and occurrence in the pre-Cambrian 

 complex of Fenno-Scandia." The subject is one in which 

 the author has already made a reputation. Like Hinter- 



