296 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



t*Cardium sphseroideura, Forbes. t*Serpula (Vermetus) concava. 



Trigonia caudata, Agass. Gervillia alaeformis (Perna, Sow.). 



t* ornata, d'Orl/. (T. spinosa, var., * Forbesiana, d'Orb. (solenoi- 



Sow.) des, Forbes.) 



t* ca,r'mata,, Agass. (T.harpafLeym.) *Pinna Robiiialdina, d'Orb. 



* Dtedalea, Parkinson. *Lima CottaldinaJ, d'Orb. 



Area Raulini. Pecten quinquecostatus, var. ?, Sow. 



* securis. interstriatus, Leym. 8f d'Orb. 



exaltata, Nilsson. Ostrea prionota ?, Goldf. 



t* Carteroni, d'Orb. carinata. 



t*Astarte multistriata. * Leymerii, Desk. 



t* substriata, Leym. Hinnites Leymerii, Desk. 



* numismalis ?, d'Orb. Gryphsea sinuata, Sow. 



*Corbis corrugata, d'Orb. (SphcBra, * haxYta, (semipUcata, vox.). 



Sow.) Terebratula sella, Sow. 



t*Venus striato-costata, Forbes. *Ammonites furcatus, Sow. 



t Ricordiana, d'Orb. Deshayesii. 



t Cornueliana, d'Orb. * Leopoldinus, d'Orb. 



t* ovalis, var. elongata. * inflatus. 



Thetis minor, Sow. *Nautilus radiatiis, Sotv. 



tMytilus simplex. Desk. *Heteropora ?, Sow. 



* lanceolatus, Sow. * ? gracilis. 



t bellus. t*Astr8ea ? elegans (new species). 



fPerna Mulleti, Leym. *Holaster complanatus {Spatangus re- 



f * Ricordiana, d' Orb. 



3. The Atherfield Clay. — I give this name to the great bed next 

 above the Perna group, in preference to that of "Fuller's Earthy* 

 (of which this clay has many of the characters,) to prevent its being 

 confounded with the beds well-known in Surrey under the latter name§, 

 but which belong to a much higher part of this series. It is here 

 usually of a drab colour passing into bluish grey, and includes flat 

 nodular masses like the smaller nodules hereafter mentioned in No. 4, 

 which there contain astacoid remains. Among the fossils the most 

 common in the lower portion is Pinna Robinaldina, d'Orb. Ammo- 

 nites are not unfrequent ; and the remains of a turtle, now in the 

 cabinet of the Geological Society, were obtained here. 



The facility with which such a clay as that above described, melts 

 down under exposure, may readily be imagined. The encroachments 

 of the sea on this part of the coast are rapid and unceasing, but the 

 progress of what is called a "founder" is very gradual |1 ; unlike that 



'% Lima Cottaldina, d'Orb. — The specimens of this fossil, formerly referred to 

 L. elongata, appear to be distinct from that figured in the ' Min. Con.' and de- 

 scribed by Mr. Sowerby as having sixteen smooth and rounded ribs ; whereas in 

 these specimens the ribs are more than twenty, sharp and imbricated by the lines 

 of growth, with an intervening small ridge at the base of each furrow, the sides of 

 which are sometimes striated. From these characters and its general form, it is 

 probably the L. Cottaldina, d'Orb. The species is certainly the same as one found 

 in the Kentish quarries. — M. 



§ No clay precisely like the true Fuller's earth of Reigate and of Nutfield occurs 

 in the section now under consideration ; nor has any such been yet found on the 

 coast near Hythe ; — another proof of the want of exact identity even in continu- 

 ous deposits. 



II During the summer of 1844, a portion of the cliff on the south-west of the 

 Coast-Guard Station, about 150 feet from east to west, and 80 feet on a line at 

 right angles to the shore, was found to be separated from the main land by a 

 narrow crack. The mass thus marked out subsided gradually, the ruins below 

 advancing steadily into the sea ; and when I saw the place again a few weeks 

 afterwards, the subjacent Perna beds, which previously formed the point, were 



