Reviews — Geological Survey of England and Wales. 179 



Two years ago we called attention (Geol. Mag. April, 1877) to 

 a short memoir on the Geology of the eastern end of Essex, by 

 Mr. Whitaker ; we have now the pleasure of announcing the publi- 

 cation of the above-mentioned work, by the same geologist, in 

 conjunction with three colleagues. Most of the field-survey was 

 done (we are told) by Mr. Penning ; while Mr. Whitaker himself 

 has performed the duties of editor, in his invariably careful and 

 systematic style. 



Much of the country described is comparatively little known 

 to geologists. It lies chiefly in Essex, including the towns of 

 Braintree, Coggeshall, Dunmow, Halstead, Saffron Walden, Harlow, 

 Thaxted, and Witham. In Hertfordshire is included the country 

 around Bishop's Stortford, Buntingford, Hertford, and Ware ; in 

 Cambridgshire, that around Linton and Eoyston; and in Suffolk, 

 that around Haverhill, Long Melford, and Sudbury. The previous 

 observers include the late Bev. W. B. Clarke, John Brown, of 

 Stanway, J. Mitchell, Prof. Prestwich, and Mr. S. V. Wood, Jun. 



Geologically the area consists of a great plain of Chalky Boulder- 

 clay, beneath which, in the valleys, are exposed glacial sands and 

 gravels, Tertiary deposits, and Chalk. In the north-western corner 

 of the area a trace of Gault is exposed, and bordering this, near 

 Eoyston, the Chalk stands out in comparatively bold hills : rising 

 even to 550 feet above the sea-level at Tharfield, where capped by 

 the Boulder-clay. 



About half the area beneath the Drift is occupied by Chalk, and 

 nearly half by the London Clay, between which a belt of the Lower 

 London Tertiaries, comprising Beading and Thanet Beds, has been 

 traced, and not without considerable difficulty, owing to the covering 

 of Drift. 



A detailed description of the various rocks in the numerous pits 

 and cuttings examined, forms the main feature of this work; the 

 initials of each observer being appended to his statements. 



Some disturbances in the Chalk are figured, in one of which cases 

 the beds are tilted at an angle of 60°. Lists of fossils from the 

 various pits are given on the authority of Mr. Etheridge. The 

 account of the Eeading Beds is partly re-printed from Mr. 

 Whitaker's Memoir on the London Basin. The description of the 

 Thanet Beds is new, as they were only discovered in this area in 

 1873, during the progress of the Geological Survey. In the same 

 year Mr. Whitaker also discovered traces of the Eed Crag at Sudbury. 

 A short description of these is given, with a list of the organic 

 remains which were in the state of casts or impressions. 



Descriptions of the glacial deposits occupy about a third of the 

 work. We should gladly have seen some more definite scheme of 

 classification adopted for these beds, but we are told that " until the 

 work of the Geological Survey in Norfolk and Suffolk is in a more 

 advanced state, it is better for us not to commit ourselves to a 

 scheme of classification, and to be content with the detailed mapping 

 of the beds and their lithological description." 



Such being the case, the work cannot possess so much interest for 



