NA TURE 



[December io, 1908 



SO'SIE RECENT PUBLICATIONS 

 GEOLOGICAL SURVEYS. 



OF 



'T'HE aclive Geological Survey of Great Britain has issued 

 its" Summary of Progress for 1907 " (igoS, price is.), 

 whicli is no mere departmental report, since it contains 

 a number of original memoirs. One of these is by Dr. 

 Klett, on the rocks styled mugearites, which may be de- 

 scribed as dolerites rich in oligoclase and olivine, but poor 

 in augite. These have now been found among the 

 Carboniferous lavas of East Lothian and Midlothian, where 

 they closely resemble Mr. Marker's original Cainozoic 

 types from Skye. Two other memoirs deal usefully with 

 new sections along English railways. Perhaps the most 

 interesting feature of the general descriptions of the year's 

 work is the insight given (p. 66, &c.) into the progress 

 of the survey of Mull, from which much that is new may 

 be e.\pected. 



The full memoir on " The Small Isles of Inverness-shire 

 (Rum, Canna, Eigg, Muck, &c.)," by Messrs. Harker and 

 Barrow, is now also published (1908, price 4s. 6d.). In 

 chapter iii., the Mesozoic strata of Eigg and Muck are 



dealt with ; Upper Cretaceous sandstone, 2 feet thick, has 

 now been discovered in Eigg, resting on Oxfordian shales. 

 Mr. Harkor, following the lines of his masterly memoir 

 on Skve, reports on the igneous series of Cainozoic age 

 which forms the main mass of the islands. He lays much 

 stress on the occurrence of intrusive sills, which have 

 been regarded previously as lava-flows. Tuffs and gravels 

 occur, and numerous true basaltic flows ; but the author 

 ■believes the famous mass of pitchstone that forms the 

 Sgiirr of Eigg to be intrusive in the sills and lavas, and 

 not a flow resting in an old valley-floor. This matter has 

 already been discussed before the Geological Society of 

 London. We have similarly heard already of the Cainozoic 

 gneisses of Rum, produced by the intrusion of granite into 

 cucrite (p. 105) ; but here we have a complete account of 

 them, in which their similarity to some of the pre- 

 Cambrinn gneisses is pointed out. It is, of course, well 

 known from field-observations by Callaway and others that 

 some of our ancient banded gneisses have also arisen from 

 an intermingling of acid and basic igneous rocks. 



The southern part of the Derbyshire and Nottingham- 

 shire coalfield is dealt with in a memoir explanatory of 



SO. 2fUI. VOL. 79] 



Sheet 125 (.190^. price 35.). The accompanying map 

 (is. bd.) was drawn up in 1907, and includes the drifts, 

 which here play no great part in the siu'face geology. 

 The " solid " rocks range from Carboniferous Limestojic 

 up to Keuper marl, and almost all provide material o( 

 industrial value. Even the lead-mines in the north-west 

 of the area show signs of revival. Messrs. Gibson and 

 Wedd furnish an interesting sketch of the great variety 

 of scenery to be met with in the country north of Derby. 

 The term " Yoredale rocks " has been abandoned in this 

 area (p. 8), but the typical " Pendleside series " has not 

 as yet been traced. Numerous new observations are made 

 on the coal-bearing strata, and the drifts are now described 

 for the first time. In the north-east of the area, certain 

 esker-like mounds (p. 165) are referred to the action of 

 the Irish Sea glacier, which sent out a lobe thus far into 

 the Midlands. 



Mr. \V. -A. E. Ussher describes " The Geology of the 

 Quantock Hills and of Taunton and Bridgwater " (1908, 

 price 2s.) in a memoir accompanying Sheet 295 (1907, 

 price IS. 6d.). The map gives a picture of the great 

 alluvial flat at Bridgwater, above which the Ouantocks, 

 formed of hard Devonian 

 strata, rise boldly on the west. 

 The occurrence of Carbonifer- 

 (lus Limestone at Cannington 

 Park, and of cherty Lower 

 Culm-measures resting on 

 Upper Devonian in the region 

 to the south-west, gives rise 

 to an interesting discussion 

 'P- 33). '" which it is urged 

 that these two series are 

 i-ontcmporaneous. Mr. H. B. 

 Woodward adds a chapter on 

 I he Lower Lias near the 

 Bristol Channel north of 

 Williton. 



The memoir on '* The 

 (leology of the Country 

 around Oxford," by Messrs. 

 Pocock, H. B. Woodw^ard. 

 and Lamplugh (1908, price 

 2,?. 3d.), accompanies a speci- 

 ally arranged map with Ox- 

 lord in the centre (1908, price 

 IS. 6d.). 'Ihese publications 

 are sure to have a rapid sale, 

 and the colour-printed map, 

 although it includes drifts, 

 gives a very clear indication 

 of the structure of the coun- 

 try. Mr. Lamplugh places 

 the Shotover Sands (p. 66) as 

 Wnalden ; on the east, near 

 Great Milton, they are over- 

 lain by Gault, apparently 

 without the intervention of 

 marine Lower Greensand 

 has been noticed elsewhere 

 The plateau-drift, a deposit 



, l;ay, L.gi 



I Strata. This unconformity 



j (p. 75) by Dr. .\, M. Davios 

 older than the highest alluvial terraces of the streams, 

 correlated (p. 102) with the chalky boulder-clay of regions 

 to the east. Might we not ask, in a memoir of such 

 wide interest, for some of the photographic illustrations, 

 connecting surface-features and geological structure, which 



i are so liberally furnished by the survey for less accessible 

 districts? Large parts of rural and industrial England 

 still require adequate illustration. In this matter, colonial 

 surveys are a bright example to us. 



In the concluding part of the Jahrbticli der k.k. geo- 

 logischen Reiclisanslalt for iqoy, Ivii. Band (1907), Dr. 

 F. E. Suess describes (p. 793) the structure of the narrow 

 Carboniferous basin of Rossitz, on the Bohemian and 

 Moravian border. The Culm-measures and Devonian 

 strata are unconformably overlain, and mostly concealed, 

 by Upper Carboniferous and Permian beds, to many of 

 which a desert origin is ascribed. Periodic floods swept 

 down banks of pebbles, and some of the Carboniferous 



j conglomerates are regarded as the remains of land-slides. 



I The great intrusive masses of granite and diorite in the 



