264 Mr. Lonsdale on the Oolitic District of Bath. 



The grit or siliceous rock is composed of fine grains of quartz, which 

 exhibit in general great uniformity of size in the same mass. Occasionally, 

 from a thin coating of lime upon some of the grains, the stone assumes an 

 oolitic character. Organic remains are scattered through all the beds, and 

 are frequently so numerous as to change the grit into an impure, shelly lime- 

 stone. The masses or irregular beds of stone possess no definite cleavage, 

 and are generally so hard as to require the aid of gunpowder in dividing 

 them. On being broken, the fractured surface often presents small, shining, 

 parallel facets. In some localities a friable stratum occurs, which consists 

 almost entirely of decomposed fragments of shells. The colour of the grit is 

 principally pale brown on the exterior, but blue in the interior. 



The accompanying lists are given, to illustrate the connexions between the 

 stone and the sandy strata. 



Quarry at the foot of Seend Hill, and on the south-east side of the Trow- 

 bridge Road. 



Top. Ft. In. 



Grit, split into irregular laminae, 1 foot to 3 feet 2 



Sand, with occasionally masses of grit 1 6 



Grit, with many fragments of shells 1 



Sand, inclosing in some parts nodules of grit. 



Very finely-grained grit, containing numerous fragments of shells, 

 and composed of flat masses, which are sometimes in contact, some- 

 times separated by sand 1 



Sand 3 



Sand, with numerous fragments of shells, and intermixed with clay . . 3 



Sand, containing masses of grit 2 feet to 4 feet 3 



Grit, 4 to 6 feet, in some parts separated into two beds by a layer of 



sand 6 inches thick 5 



Sand, 6 to 18 inches 1 



Grit, a very hard stone 1 4 



Sand 1 6 



Grit 1 3 



Sand 3 



Quarry at Spirthill, between Calne and Lynham. 



The clay which separates the coral rag from the lower calcareous grit 12 



Grit 10 



Sand, containing much calcareous matter, and thin laminae of clay : 



greatest thickness 3 6 



Irregular beds of calcareous grit, varying in their characters, and near 

 the upper part assuming the appearance of a blue, shelly, impure 



limestone 6 



Sand. 



The surface occupied by the coral rag in the district to which this memoir 



