July 31, 1913] 



NATURE 



569 



during the Pliocene uplift is illustrated (p. 70) by 

 the case of the Dart, which lowered its floor below 

 the general platform of the country by 700 ft. The 

 freshness of the rock on such valley-sides is in marked 

 contrast with the depth of decomposed rock found 

 (p. 27) across the moor. So well-written a memoir 

 on a district visited by thousands of tourists would 

 gain much in popularity if it were illustrated by views 

 of scenery. Wistman's Wood (p. 60) in its desolate 

 surroundings is a geographical feature in itself. Such 

 appeals to the_ general taxpayer seem, however, to be 

 largely the privilege of the Scottish branch of the 

 Survey, and, as we have remarked on previous .occa- 

 sions, England, with all its rich associations, still 

 awaits adequate illustration. 



A considerable step, however, is made in this direc- 

 tion in W. A. E. Ussher's memoir on Ivybridge and 



appear to belong to the Ordovician kiilas s-eries. At 

 Lizard Head, however, they strike north-north-west, 

 and this is taken as strong evidence of their pre- 

 Cambrian age. To mention quite another feature 

 among the many described in this important memoir, 

 on Crousa Down a gravel of blocks of vein-quart/ 

 resting on gabbro is regarded (p. 231) as probably a 

 marine deposit of Pliocene age. It is now 364 ft. 

 above the sea. The map (is. 6d.), covering the 

 country from Constantine to the Lizard, will surely 

 accompany all future scientific visitors. 



W. Gibson, in a special memoir (1913, price is. 6d.), 

 describes the concealed coalfield of Yorkshire and 

 Nottinghamshire, with a map showing by contours 

 the depth of the Coal-Measure surface below the 

 Triassic and Permian covering. North-cast of Leeds 

 5000 ft. of Upper Carboniferous strata were removed 



Fir,. i.— Fluvio-glaeial 



Terminal moraine beyond. 

 Stationery Office.) 



(Reproduced by pei 



of the Conttoller of H.M. 



Modbury Ijs.l, in explanation of Sheet 349, and by 

 J. S. Flett and J. B. Hill in dealing with Sheet 359, 

 the Lizard and Meneage area. In the former, we see 

 the romantic crag of the Dewerstone, and in the latter 

 the purple rocks of Kynance Cove and the folded 

 schists on Lizard Head. The Lizard memoir (5s.) 

 naturally has immense petrographic interest. New 

 analyses are given of rocks that serve as types to 

 English students, and the changes are traced from 

 massive intrusive bodies to foliated schists (p. 97, &c). 

 The Kennack Gneisses (p. 129) afford a clear example 

 of the penetration of a dolerite by a granitic magma, 

 the gneissic structure beincr due (p. 140) to " injection 

 foliation." Sedimentary schists are also present in the 

 south and in the north-east of the area (pp. 34 and 

 167), and in the latter district, near Manaccan, they 

 NO. 2283, VOL. 91] 



by denudation before first Permian beds were laid 

 down (p. 27). 



The Scottish branch deals in. Memoir 93 (4s.) with 

 a moorland district, where Ben Wyvis rises as a flat- 

 tonned relic of an old plateau of metamorphic rocks. 

 The maps of the Scottish Survey (2s. 6d. each) cover 

 individually a much larger area than those of Eng- 

 land, and the work on Sheet 93 must have often 

 seemed monotonous. The glacial and other super- 

 ficial deposits are shown by stippling over the colour- 

 printing- used for "solid" rocks, and we no longer 

 have the anomaly of peat and alluvium represented in 

 colour and boulder-clay and glacial gravel omitted 

 altogether. Fresh-water alluvia, however, still receive 

 a separate colour. The contributions by J. S. Flett 

 contain, as usual, much original matter. A riebeckite- 



