256 Dr. FiTTON on the Strata below the Chalk, 



streams on the north and east of that point, must be referred to the Portland sand ; which, there- 

 fore, seems here to be more like that of the coast than of Oxfordshire and Bucks. At Tisbury, 

 I was informed, sand is found, but not more than 18 inches thick, beneath the lowest beds of 

 the Portland stone. 



Kimmeridge Clay. — The whole of the level tract on the west of the opening of the vale seems 

 to be occupied by clay; and this I have referred to that of Kimmeridge, on the following 

 grounds, which, it must be acknowledged, are not very satisfactory. The gault and this clay 

 come into contact, on the north of Shaftesbury, and beneath the heights of green-sand at East 

 and West Knoyle, — in consequence of an overlapping of the whole cretaceous group, analogous 

 to what is observable in Devonshire. The lower clay, which is used for brick -making on the west 

 of Shaftesbury, contains Panopcea depressa, and casts of Ammonites like those of Kimmeridge, 

 with other fossils, and includes a band of Septaria, there called " Turtle-stone ". I myself found 

 a Pullastra ? about a mile south-west of Pythouse, at the brick-field of Great Mead (or Moat) 

 on the north of Semley ; and Miss Benett states that clay with the Kimmeridge fossils occurs at 

 Binley Farm {Quce. Linley of the Ordnance Map ?), on the west of Pythouse. I did not hear of 

 any bed of stone between the heights of Shaftesbury and Knoyle. It is not, however, impro- 

 bable, that outliers of the gault or Upper green-sand may exist within that tract. But whether 

 the Oxford clay also does not occur in the remoter part of the low country on the west of the 

 escarpment, — the Oxford oolite as well as the Portland strata being wanting there, — 1 could 

 not ascertain. 



(136.) Stourhead. — I regret that it was not in my power to examine the 

 heights on the west of Mere^ which, according to Mr. Greenough's Map, 

 consist of the green-sands projecting beyond the chalk escarpment; since, 

 from the information of a friend, to whom I am indebted for the subjoined 

 sketch and hst of the strata, the Lower green-sand may be more conspicuous 

 there than on the confines of the Vale of Wardour; which would prove 

 that this group, like the Upper sand, is alternately expanded and again re- 

 duced in bulk and development. 



The subjoined section extends from the chalk on the east of Stourhead, to the clay beneath 

 the hill on which Alfred's Tower is placed, which is said to be 817 feet above the sea. 



White-Sheet Hill. 



Xina's Alfred's J— 



Settle Hill. Tower. Lake. Temple. Quarry. Well. / 



. . / 1 Chalk. 



i33y2SDra^'g^i|aii ■■rg^rTrr'rvyrm-r^r^^ ', Chalk-Marl. 



~ " '' '" '"^''-' '^'^'^'^''^^^'^^'^-^^^^^^ ^'""^' 



^^^m^^^^^^^^MS,^^^^^^^^^^^^^^^^^ Clay. 



1 . Represents the Upper Chalk. Feet. 



2. Chalk Marl, here called " Malm ". In this a well had been sunk, which afforded the 

 following strata, by report of the well-sinker : — 



a. "Malm"; like the chalk-marl of Lewes in Sussex, full of the characteristic! ,^(» 

 fossils : sharks' teeth in great abundance J 



b. " White Stone" ; so called, but in reality rather gray or green : full of Ammonites, 1 j, 

 many of which preserve their iridescent coats j 



