524 Correspondence — R. M. Bnjdone. 



Radnorshire (1912), by Mr. Lewis Davies, is described as a pastoral 

 couuty -with many sheep- wallis, with no coal, no sea-coast, and no 

 liver of commercial utility, but formed of valleys, moorlands, and 

 a mountainous tract, known as Radnor Forest. Many good views of 

 the physical features are given, including the great artificial lake of 

 the Caregddu Reservoir in the Elan valley constructed for the water- 

 supply of Birmingham. The geology relates almost wholly to 

 Ordovician, Silurian, Old Red Sandstone, and Igneous rocks. Brief 

 accounts of them, of glacial phenomena, of mineral springs, and stone 

 quarries are given. 



VJ. — Brief Notices. 



1 . !NoRTH OF England Geology. — Some points of general interest 

 are mentioned in a paper on " Lamprophyre Dykes in Long Sleddale, 

 Westmorland " by Mr. Alfred Harker in the September number of 

 The Naturalist. The bearing of these dykes is E.jS'.E., directly 

 towards the Shap granite, 4 miles distant, and one peculiarity is 

 the occurrence of numerous small spherical structures, the result of 

 oozing -in of the final residual magma (wholh' felspathic in 

 composition) into steam-cavities. The same part contains a popular 

 geological account of "The Evolution of Bridlington", by Mr. T. 

 Sheppard, who contributes also an account of a lithographed map 

 of South Yorkshire by William Smith, the '"Father of English 

 Geology ". This map, dated 1819, and reproduced by Mr. Sheppard, 

 has hitherto escaped record. 



2. Geological Map of jS^oeth America. — Under the title Geologic 

 Map of North America the United States Geological Survey has 

 published (dated 1911) a new and much improved edition of the map 

 described by me in the Geological Magazine for 1906, p. 564. The 

 pi'ice of the complete map in four sheets is 75 cents or 3s. carriage 

 free. The scale is 1 : 5,000,000 or 78-9 miles to 1 inch. In the first 

 edition only twenty-fi.ve divisions of rocks were shown. In the new 

 edition forty-two divisions are indicated. Another improvement is 

 the insertion of additional place-names, which enable one to identify 

 localities better. Several of the blank spaces in the first edition are 

 now geologically coloured, e.g. Nevada, Idaho, California, Arizona, 

 New Mexico, l^aja California, Yukon, and part of Alaska. One 

 cannot help envying the Americans, whose Government, unlike our 

 own, supplies such excellent maps at so low a price. — B. Hobson. 



CO i?,i?,ES^'onsrnDE3srcE:. 



THE DEVONSHIEE CHALK CLIFFS. 



Sir, — I recently spent four days running over the Devonshire chalk 

 cliffs with the help of Dr. Rowe's admirable guide, and it seemed to 

 me that he had not done quite full justice to those west of Branscombe 



Mouth. 



