456 Geological Society. 



7. Below the Portland stone, and dividing it from the Kimmeridge 

 clay, the authors establish a deposit, hitherto unnoticed, of sand and 

 sandstone 80 feet thick, which they call the Kimmeridge sandstone; 

 it is full of grains of green earth, and scarcely distinguishable, ex- 

 cept by its fossils, from the greensands immediately below the 

 chalk: they also have ascertained that the pseudo-volcano still burn- 

 ing on the north of Weymouth is in the bituminous beds of the 

 Kimmeridge clay, and that there has been at some unknown former 

 period a similar combustion of the same clay on the shore near 

 Portland ferry. 



8. The Oxford oolite is very fully developed near Weymouth, as 

 it is near Scarborough, passing into beds of sand, sandstone, and 

 clay at its upper and lower extremities ; containing Ostrea deltoi- 

 dea in the upper, and Gryphaea dilatata in the lower beds ; and 

 gradually passing into Kimmeridge clay above, and into Oxford clay 

 below : its thickness exceeds 150 feet. The history and character of 

 this oolite formation at Weymouth have been fully described in all 

 their details, and accompanied by a valuable list of its fossils, in a 

 paper on the strata of the Yorkshire coast, by Professor Sedgwick ; 

 Ann. Phil., May 1826. 



9. The Oxford clay is about 300 feet thick, and contains large 

 septaria, which are cut into beautiful tables, under the name of 

 Turtle Marble. This clay abounds throughout with shells of Gry- 

 phaea dilatata. 



10. The cornbrash and forest marble form the axis of the Valley 

 of Weymouth, and occupy much of the Valley of Bredy. The forest 

 marble formation abounds in beds of clay, and is often composed 

 of clay without the marble. The Bradford Encrinite (Apiocrinites 

 rotundus) is found in several parts of it, e. g. at Abbotsbury, at 

 Bothenhampton, and in the cliff west of Bridport Harbour. 



11. There is no Bath oolite stone in Dorsetshire, but the inferior 

 polite occupies a large extent near Bridport, affording coarse lime- 

 stone, like that of Dundry in its upper, and micaceous sand with 

 beds and concretions of calcareous sandstone in its lower part. Its 

 total thickness is about 300 feet. Near its middle region are masses 

 of breccia, containing slightly rolled fragments of the lower strata, 

 and having the entire circumference of these fragments drilled all 

 over by some small lithodomous shells ; these fragments attest the 

 consolidation of the lower strata before the deposition of the 

 central beds, and mark an interval in the formation sufficient for 

 the fragments to have been rounded and perforated. 



12. The lowest strata, within the district described, are the upper 

 marl beds of the lias formation on the east of Charmouth ; these 

 are loaded with belemnites, and may represent the Calcaire a 

 Belemnite of the French geologists ; as the lower stony beds of 

 lias at Lyme are equivalent to their Calcaire a Gri/pkite. On the 

 shore east of Charmouth the marl beds present an almost continu- 

 ous pavement of belemnites, and also contain saurians. 



13. The elevation which has raised all the component formations 

 of the Valley of Weymouth towards an anticlinal axis, has been ac- 

 companied 



