BRITISH ISLES. 3 



Mr. Barnett gives the following definition of elvans : — " The Cornish 

 Elvans are rocks occurring in veins or dykes composed of two or more 

 of the following minerals in variable proportions — quartz, felspar, mica, 

 schorl, and chlorite — the base being granular or compact, and gene- 

 rally containing imbedded crystals of its components, which render it 

 porphyritic." After separating them into six different groups, he gives 

 a description of sixty-two elvan-courses, mentioning the principal 

 quarries or mines where sections may be seen. Yery little is said about 

 the greenstones and sandstones. C. L, N. E. 



Barr, Thomas M. On the Geology of the North-Eastern District of 



Yorkshire. Trans. Geol. Soc. Glasgow, vol. iv. part 3, pp. 291-300, 



plate (map). 



A general account of the geological features of the country between 



the Tees and Eskdale. The map, on the scale of six miles to an inch, 



shows roughly the boundaries of the Upper Oolite, Oolite, Lias, Trias, 



and Permian. A short analysis of statistics as to the produce &c. of 



the Cleveland iron-ore is given. • G. A. L. 



Barrow, J". The Dynfi Mineral District. Plates 22-29 (map and 

 sections) issued with Proc. S. Wales Inst, of Eng. vol. viii. no. 5. 

 Discussion, ibid. vol. ix. no. 1, pp. 12-17. 



Bassett, A. The Diamond Drill. Trans. N.Engl. Inst. Eng. vol. xxiii. 



plates xxxvi.-xl. 

 Gives sections of Coal Measures passed through in borings at Risca 

 [?and elsewhere]. 



Beddoe, Dr. J. Address to the Department of Anthropology. Rep. 

 Brit. Assoc, for 1873, Sections, pp. 134-140. 



The author points out the threefold division of Yorkshire — not that 

 into ridings, but that marked out by nature. (1) The western moor- 

 lands — the region of Carboniferous Limestone and Millstone Grit, of 

 narrow valleys, and cold rainy moorlands. (2) The Plain of York — 

 the region of the Trias, monotonously fertile; to this the plain of 

 Holderness and the vale of Pickering may be regarded as eastern ad- 

 juncts. (3) The eastern moorlands and wolds; these are the most 

 important parts of Yorkshire to the prehistoric archaeologist. Largo 

 as the county is, and sharply marked off into districts by striking di- 

 versities of geological structure, climate, and surface, there is an ap- 

 proach to unity in its political and ethnological history which could 

 scarcely have been looked for. AV. T. 



Bedwell, E. a . The Isle of Thanet. The Ammoni to Zone, the DepI h 



of the Chalk in Section, and the Continuity of its Elint Floorings. 



Geol. Mag. dec. 2, vol. i. pp. 16-22, 94 (map and sections). 



The total thickness of Chalk in the cliffs of the Isle of Thanet is 



180 feet. The highest bed is seen at Eoreness, the lowest near Pegwell. 



The author has marked the positions of 89 large Ammonites (which 



average 3 feet in diameter), taking as a datum the double line of 



nodular flints which is exhibited nearly continuously from Birchingtoa 



b2 



