248 INIr. Lonsdale on the Oolitic District of Bath. 



Top. Ft. In. 



Micaceous, yellow sand 4 



Pale brown marlstone, containing numerous fragments of shells 2 



Chocolate-coloured marl, inclosing nodules of limestone with ferruginous, 



oolitic particles, and numerous fragments of Ammonites, Belemnites, &c. .. 6 



Light-grey marlstone 1 



Indurated, pale chocolate marl 6 



Micaceous, sandy, yellowish marl 4 



Chocolate-coloured marlstone 3 



Micaceous, yellow sand, containing thin layers of clay, and tabular masses of 



fissile, micaceous, blue sandstone 3 



The deposit in some places consists of large masses of micaceous, sandy 

 marlstone, in which are imbedded numerous individuals of a large Pecten 

 with obtuse ribs. 



Though the "marlstone" is probably co-extensive with the hills surround- 

 ing Bath, yet it is very rarely to be seen. I have noticed it only at Box, 

 Batheaston, and the descent from High Barrow Hill to Pennycuick Bottom 

 near Tvverton, Mr. Smith gives Bathhampton and the Coal Canal as two 

 of his localities. 



Ammo7utes Strangwaijsii of Sowerby *, the Ammonites imdidatns of Smithf, 

 abounded at Box. 



Inferior Oolite. 



This formation consists of nearly equal divisions of limestone and sand. 

 The following- section was obtained from Widcombe Hill near Bath. 



Fuller's earth 17 feet. 



Limestone 60 



Sand 70 



Lias upper marl 20 



The accompanying" table exhibits the arrangement of the subordinate beds 

 of the inferior oolite. 



Principal divisions. I 



1. Limestone. | a 

 b 

 c 



2. Sand. 



Subordinate divisions. Tliitkness. 



Soft freestone more or less oolitic 40 to 50 feet. 



Rubbly stone, consisting principally of corals 10 



Hard, brown limestone, abounding with casts of shells .... 6 

 Slightly calcareous, and containing irregular courses of con- 

 cretions of limestone 70 



(1 a.) The freestone strata consist in the upper part of a distinctly oolitic 

 stone, which cannot be distinguished lithologically from the great oolite. 

 The lower beds contain a greater proportion of sand : they are of a brownish 

 colour, and are scarcely oolitic. 



* Min. Con. tab. 25fl. f. 1. 3. t Stratigraphical System, p. 114 : Marlstone-Plate; fig. 3. 



