THE RAILWAY SECTIONS. 83 



thickness of the London clay, in some situations, 

 is estimated at nearly 1,000 feet; the wells on the 

 Surrey side of the Thames are from 100 to 600 

 feet deep. 



The Railway sections. — The above pre- 

 liminary remarks will enable the observer to un- 

 derstand the nature of the strata of which transient 

 glimpses may be obtained on each side the railway 

 in the rapid transit from London to Southampton, 

 on which we now proceed without further com- 

 ment. Although no considerable sections of 

 the eocene strata are traversed by this line, yet 

 here and there the characteristic soil of the Lon- 

 don clay may be seen in the cuttings, where the 

 surface has not acquired a covering of turf. On 

 Wandsworth Common the banks on each side are 

 composed of this clay with a superficial capping 

 of gravel and sand. When the railway was in 

 progress numerous fossils were dug up ; and even 

 now the slips of the embankments which occa- 

 sionally take place, expose specimens of nautili 

 and other shells, petrified wood, &c* 



of the Paris basin, and the underlying chalk, firestone, and gait, to the green- 

 sand. The water rises in a powerful column to the height of 30 feet above 

 the highest part of Paris, and has a temperature of 91° Fahrenheit ; being 

 sufficiently warm for the heating of green-houses, &c. 



* See " Geological Survey of Surrey" in iirayiey's History of the County, 

 vol. i. pi. 1, 2, in which several of the fossils discovered in the clay of Wand.s- 

 worth Common are figured. 



