Dr. FiTTON on the Strata below the Chalk, 285 



Lower green-sand. — A considerable thickness of sand occurs at the top of the ridge above men- 

 tioned, in the space between Stone, Dinton, and Cuddington. It attains its greatest height near 

 Stone, where there is a knoll apparently composed of sand ; near which the following beds were 

 found ; — 



Sand-pit at Stone. 



Vegetation and soil about 1 ft. to 



1 . Greenish clay, like Fuller's earth 6 in. to 



2. Grey sandy clay 9 in. to 



3. Rust-coloured sand, passing downwards into grey : the lower boundary is ill defined 1 „ 



and irregular 1 ft. 6 in. to J 



4. Whitish uniform sand, marked by nearly horizontal but irregular lines, of darker hue, 1 „ 



grey, yellow, brown, and nearly black about J _ 



Ft. 



III. 



3 











9 



1 



ti 



Total depth 15 



Some remains of the Lower green-sand appear also at the top of most of the sections following, 

 which are only a selection from a great number of lists. The series in all parts of the country is 

 very nearly alike : but the pits being worked for the sake of tlie Portland stone, have not, gene- 

 rally, been opened in the places most favourable to the display of the superior strata. 



The circumstance most deserving of notice in the sections at Ford, and thence towards Dinton, 

 is the occurrence, near the bottom, of dark clay which includes a layer of iridescent Mytili, cor- 

 responding precisely in its character and situation to that at Bishopstone, Whitchurch, and other 

 places hereafter mentioned. 



Dinton Quarries, — One of the most remarkable quarries in this part of the country, is on the 

 south-west of the cross-road from Dinton to Cuddington, where the works have been carried on 

 for more than 200 years, the stone being of excellent quality. The Section was as follows : — 



Stone-pits at Dinton. 

 All the beds inclining a little to the east. 



1. Vegetable soil, and reddish loam about 



2. Ferruginous sandy loam 



3. Greenish grey clay 



4. Brownish and grey clay 1 ft. 3 in. to 



[The great variation in thickness of this bed arises from its entering at the bottom 

 into the irregularities on the surface of 6. which are coated throughout with the in- 

 termediate thin bed of clay (5.)] 



5. Dark, umber-brown, tough clay, with much oxide of iron 2 in. to 4 



At the bottom of the bed are Mytili, and decomposed fragments of other shells. 



\_Purbeck Strata.'\ 



6. Grey clay and soft stone (freshwater limestone) becoming white at the bottom by de- 



composition : at the lower part more continuously laminated, but including through- 

 out irregular masses of stone, in some places penetrated by minute tubular cavities, 

 slightly bent and of uniform diameter, — probaby the work of lithophagous animals, 

 or such as might be produced by the removal of slender twigs. The decomposed 

 parts of this stratum pass into the firmer masses; as in the " Malm " of Garsington. 

 It contains a few spiral univalves like those of that place and Combe Wood, including 



Palvdina (elongata ?), with small Modiolae, and a Cyclas 1 



(3 feet thick in an adjacent pit) .... J 



7. Between 6. and 8. is a thin bed of tough, dark, somewhat ferruginous ? clay, with iri- 



descent Mytili {M, Lyellii 1) at the bottom 



2 











6 







9 



3 







\3 



