374 Reviews — Geology of Hampstead Heath. 



(plate i), on which the sites of collieries and boreholes are marked, 

 with the depth to Coal-measures, and other information. It comprises 

 about 1,200 square miles, and tbe author remarks, in regard to the 

 accessibility of the coals, that the boring at Kelham, near Newark- 

 on-Trent, indicates that the lower seams of the Middle Coal-measures 

 (a division which contains the chief workable seams), " are well 

 within the 4,000-ft. limit of working in Nottinghamshire. In south 

 Yorkshire, from the evidence of the Thorne Boring, it is reasonable 

 to infer that they will seldom exceed this depth, while the Top 

 Hard Coal in Nottinghamshire and Barnsley seam in Yorkshire 

 should be met with under 3,000 feet." 



After a general description of the Carboniferous strata, including 

 particulars of tbe Coal-measures with its coal-seams and fossiliferous 

 horizons, the author passes on to the Permian, Triassic, and superficial 

 deposits, and gives a tabular statement of the thicknesses of these 

 newer formations as proved in various borings from Owthorpe to 

 Selby. A series of vertical sections (plate ii) also illustrates this 

 subject. There is an important chapter on the configuration, structure, 

 and limits of the coal-basin, and the map before mentioned will be 

 found of great use in the study of this part of the subject. On it the 

 contours of the concealed surface of the Coal-measures are indicated, 

 and the approximate depth to these strata, over ai'eas not yet proved, 

 can be ascertained. Diagrammatic sections are also inserted in the 

 text to explain the probable structure of the coal-field. 



Detailed records of shafts and borings are given, together with 

 a series of vertical sections (plate iii) to illustrate the Middle Coal- 

 measures above the Top Hard or Barnsley Coal. 



The volume thus contains a full account of all that is known of 

 this great and important tract of concealed Coal-measures, the details 

 being tabulated and the problems discussed by one who is a leading 

 authority on the subject. 



III. — Hampstead Heath : its Geology and Natural HisroRr. 

 Prepared under the auspices of the Hampstead Scientific Society. 

 8vo; pp. 328, with coloured frontispiece, 10 other plates, and 

 3 maps. London : T. Pisher Unwin, 1913. Price 10s. 6d. net. 



rilHIS volume, printed in bold and excellent type on thick but light 

 X paper, will justly take a high place among local natural 

 histories, and, as the several contributors show, "Hampstead still 

 offers, considering its nearness to London, considerable scope for the 

 study of nature." This especially applies to the protected area of 

 the ken Wood Estate. 



Of the three maps, one shows the contours of the land, without 

 names of places. Affixed in front of it is a geological sketch-map 

 on transparent paper, showing somewhat roughly the names of 

 principal localities, and the areas occupied by London Clay, Bagshot 

 Sand, Plateau Gravel, Boulder-clay, and Valley Drift. In this map 

 is marked the area under description, which is confined to a radius 

 of 3 miles from the Hampstead Flagstaff. The third map shows 

 the northern portion of Hampstead and part of Finchlej', but does not 

 extend over the 3 mile limit. 



