446 



figured by Mr. Walcott in his descriptions, &c. of the petrifactions found 

 near Bath, p. 22, Fig. 33. To this stratum I believe the patellita of Glou- 

 cestershire belong, and in different parts of the stratum are found 

 belemnifa. 



Above these is a SAND STRATUM, and in this is the LIMESTONE and 

 GREY SLATE STRATA of Stunsficld, Colley Weston, Chippenham, &c. 

 In this stratum, the discoidal echinita abound, as well as the trigonitce and 

 belemnitcc . In this strata are also found pinnitae^ crenatulitte, and the flat 

 fossil oyster. But the fossils which are here most abundant are the bufo- 

 nitce, and other parts of the palates and the teeth of fishes. 



On these strata lies the RAG-STONE, which has been employed for most 

 of the ancient well preserved buildings in the eastern part of the island. 

 This stone is formed of small bivalves, chiefly anomitte. 



Above this is a thick clay, on which is the limestone, called the BED- 

 FORD LIMESTONE; in which are found small gryphitce, bclemnita, ostreitte, 

 pectinitce, minute crenatulita, pinnita, a few trigonitie, the uncommonly 

 marked bivalve PI. XIII. Fig. 16. and various other shells. 



Immediately over this is a stratum of clay called CLUNCH CLAY, from 

 the beds of clunch, a soft chalk-like stone, which is found towards the 

 top of it. Ammonite, large gryphita, belemnitce, and various bivalves are 

 found in this stratum. 



Above this is the WOBURN SAND, containing in its lower parts frag- 

 ments of silicified wood. To this succeed several sand strata and clays, 

 and in one of these a thin bed of the shelly, limestone called Sussex 

 marble. Above this is the Aylesbury limestone containing large ammo- 

 nitce, gryphita, &c. 



Over this is disposed the CHALK MARL. The lower or HARD CHALK 

 rests on the chalk marl, and acquires in different parts different degrees 

 of hardness, forming in some places a white free-stone, and in others a 

 softer fire-stone. This stratum affords striking instances of the fact, first 

 noticed by Mr. Smith, of certain organic remains being peculiar to, and only 

 found lodged in, particular strata. The chief fossils which are found in this 



