GEOLOGY 



In 1891 Mr. A. Strahan drew attention to the occurrence of two 

 bands of phosphatic chalk in the neighbourhood of Taplow Court. 1 



These bands consist of brown friable chalk, the colour being due 

 to a multitude of brown grains in a white chalky paste. The grains 

 are almost entirely of organic origin, foraminifera, fragments of Inoceramus 

 and of teeth and bones of fishes, together with small oval pellets which 

 are evidently coprolites of small fishes forming the bulk, all being more 

 or less phosphatic. Two bands occur, the higher is from 8 to 1 1 feet 

 thick, and occurs at about 20 feet from the base of the Eocene strata as 

 proved in a shaft. The lower band is 4 feet thick and occurs from 1 2 

 to 19 feet lower, according to measurements made in the shaft section 

 and in a pit near the lodge of Taplow Court. Mr. Strahan observes 

 that there can be little doubt that this phosphatic chalk underlies a con- 

 siderable part, if not the whole, of the outlier of Tertiary strata on 

 which Taplow stands, but there are no other sections to prove its exten- 

 sion. Hence it appears to be strictly local. Analysis showed from 18 

 to 35 per cent of phosphate of lime. 



The Taplow phosphatic chalk bears a strong resemblance to a bed, 

 approximately on the same horizon, which has been worked in the north 

 of France. 



At Taplow the Chalk has yielded Actlnocamax (Eelemnitella) quad- 

 ratus, Osfrea acutirostris and other fossils, rather above the zone of 

 Marsupites. 



The sloping chalk plateaus, formed mainly of Upper Chalk, are 

 mostly under arable cultivation, but owing to their coverings of loam 

 and gravel the soils are often deficient in lime. Hence it has been 

 the custom to sink wells or pits in the fields to a depth of 15 or 20 feet 

 to obtain chalk for the land. The steeper slopes of Upper and Middle 

 Chalk form down land with a herbage adapted for sheep walks. Here 

 the soil is thin, and although the ploughed fields may show a brown 

 clayey or loamy soil, adjacent pits often exhibit but a trace of soil. 



Plantations of beech trees occupy many tracts in this area on the 

 borders of the plateaus and along the deep and ramifying valleys. These 

 beech woods furnish material for the important chair manufactory at 

 High Wycombe, and for sundry wooden articles made at Chesham and 

 elsewhere. The celebrated Burnham Beeches are situated partly on 

 gravel and partly on Reading Beds, but no doubt in places they are 

 rooted into the underlying Chalk which appears at the surface to the 

 north-west of Burnham Common. 



Old terraces of cultivation or lynchets occur in places, as on the 

 hillsides near Chesham, and notably on the Chalk outlier of Southend 

 and of Westend Hill, near Cheddington, where, as I am informed by 

 the Rev. F. W. Ragg, some of the best examples (locally called 

 ' lynces ') may be seen. 



The Chalk is a famous water-bearing formation, and the upper 



1 Quart. Jount. Geol. Soe. xlvii. 356. For account of the Microzoa see F. Chapman, ibid, xlviii. 

 514. 

 i 17 3 



