190 Dr. PiTTON on the Strata below the Chalk. 



lowest members of the green-sand formation^ which contains shells of many dif- 

 ferent marine genera in great numbers; — Trigonia_, Gervillia^ large Gryphites, 

 especially G. slnuata, with others decidedly marine. The bed which contains 

 these fossils is apparently the equivalent of the lowest stone beds of the coast 

 near Hythe, and is detached from the ferruginous stone at the top of the 

 Lower green-sand^ by a mass of soft, dark, sandy clay, which seems to corre- 

 spond to the middle group of Kent. 



The strata on the west of Red-clifF are so much obscured by the washing away and ruin of the 

 clay beneath the green-sands, that no continuous section is observable here. An obvious depres- 

 sion, however, corresponds to the site of the Weald-clay ; and both the clay and the sands which 

 rise from beneath it include their characteristic fossils in great abundance and perfection, and 

 contain the same large proportion of reddish and variegated marly and sandy clays, with occasional 

 beds of subcalcareous grit, as on the Sussex coast. The following details may be added to what 

 is stated in the preceding list. 



The upper part of the clay abounds remarkably in Cypris Valdensis ; and contains some nearly 

 continuous bands of clay iron ore, in elongated flattened nodules, two to nine inches in thickness, 

 including clusters of Paludina elongata. The beds above this clay form as it were the transition 

 into the green-sand formation, consisting, for some feet, of alternate layers of greenish and grey 

 sand and sandy clay of different shades, like those described above, (83.). A vertical portion of 

 the cliff at the top of the clay, which was exposed to a thickness of between 30 and 40 feet, con- 

 sisted of the following substances : 



Feet. 



Greenish-grey sand and clay in alternate bands 10 



Clay and sand with iron ore 2 



A band or course of iron ore, with Cypris i 



Greenish-grey sand, alternately of dark and lighter hues 



Bluish slaty clay, abounding in Cypris 



Clay iron ore about i 



Slaty and sandy clay 



A bed of dull, solid, earthy calcareous stone. 



Greenish-grey sandy clay 



Sand -rock, in some places very ferruginous. . 



— 



— 



20 















9 



7 







to 8 







Total, about 40 



About 770 paces from the bottom of the Lower green-sand, a bed of sand-rock, from 12 to 14 

 feet thick, makes its appearance : perhaps one of the courses of sand, subordinate to the Wealden, 

 indicated in Western Sussex by Mr. Martin. 



In this upper part of the Wealden is at least one thin bed of limestone, consisting principally of 

 the shells of a species of oyster (or Gryphsea?), of which I could not find any distinct specimens. 

 It is invested with a thin crust of fibrous, somewhat earthy, carbonate of lime, having the appear- 

 ance of what has been called " Cone in cone." In one loose specimen of this limestone, I found a 

 fragment of an Ammonite, evidently derived from some more ancient stratum, washed down and 

 lodged in the mud of which the whole of this formation is composed. The fragment is too small 

 to indicate the species, but the genus is perfectly clear. 



