186 PROCEEDINGS OE THE GEOLOGICAL SOCIETY. [Ecb. 10, 



gracilis, Terehratula semiglohosa, and Plicatula infiata. The band h, 

 in thickness about 1 foot 2 inches, is conspicuous for a meandering 

 and many-branched sponge, Siphonia jparadoxica, specimens of 

 which are visible in the cliff only in short lengths, but on the fallen 

 blocks washed by the sea are seen to extend continuously and hori- 

 zontally oA'er many square feet of surface. The underside of h de- 

 parts from the general arrangement in the other courses ; for its base, 

 instead of forming a flat or approximately flat floor, is broken up into 

 a series of irregularly rounded ridges and hollows, which undulate 

 perpendicularly within the limits of a few inches, and are represented 

 in the section. The fossUs from this bed, 5, are not so many (nume- 

 rically speaking) as those in a ; the chief forms are Siphonia jpara- 

 doocica, Terehratula hiplicata, Terehratula semiglohosa, var. undata, 

 Kingena lima, Avicula grypJiceoides, and Inoceramus latus. 



Next in succession, in descending order, is the red stratum, 

 locally called the '* Red Chalk," marked by an abundance of organic 

 remains, some of which, as Bourgueticrinus rugosus and Terehratula 

 capillata, are, in England, special to this deposit. Lithologically, it 

 is unlike the beds above it from the fact of its abounding in great 

 numbers of rolled and subangular pebbles of quartz, slate, &c., 

 which for the most part are of small size and insignificant, though 

 occasionally assuming larger dimensions. In appearance it is di- 

 visible into three almost equal portions, of which the first (A) has 

 towards its base a large quantity of fragments of Inocerami, the second 

 and thickest division (B) is rich in Belemnites, and the third and 

 lowest (C) yields many Terehratulce. The bands A and B are 

 exceedingly hard and stdny, and sufficiently tabular in character to 

 have offered a plane of resistance to former upheaving forces, and 

 to have afforded great support to the overlying white beds ; thus, 

 although the whole cliff was evidently, in ancient geological times, 

 much disturbed, the perpendicular fissures, which rise out of the 

 yellow bands (X, Y), cease just before reaching the layer B, affect 

 the red beds to the right and left of the points of application, and 

 then start upwards through the white stratum in new positions and 

 in greater number. The colouring-matter in A is less equally dis- 

 tributed than in B and C, and seems to have been accumulated 

 as an envelope around irregular spheroidal masses ; in B the tint 

 is of a lighter, and in C of a darker shade than in the highest 

 division. The middle bed (B) is in substance the hardest and most 

 homogeneous of the three ; the last (C) is the least compact. Yiewed 

 in the cliff, A wears a mottled aspect, B a nodular facies, and C 

 a plane surface. Towards the base of the bottom bed (C) the hard 

 limestone character of the Bed Chalk is lost, and the stratum dege- 

 nerates into a somewhat sandy incoherent mass, hardly differing 

 from the underlying yellow division except in colour. On account 

 of the less compact nature of the last of the three red beds, fossils 

 are more easily procured from it, have their surfaces in better con- 

 dition, and are more readily seen when of small size. Besting on the 

 top of A and filling the undulations on the underside of the lowest 

 white bed (h), is a bright red argillaceous substance, very friable. 



