Mr. Lonsdale on the Oolitic District of Bath. 257 



and yield readily to the hammer. In this state the forest marble approaches in 

 character to the rags of the great oolite. The colour of the stone is generally 

 a pale yellowish brown, but is not unfrequently blue or red, from the presence 

 of oxide of iron. Thin layers of ochreous clay traverse several of the strata, 

 and give them a striped or ribbon-like appearance. The majority of the 

 beds possess a fissile structure, by which they may be cleaved into thin flags 

 obliquely to the plane of stratification. The line of separation is determined 

 either by a layer of organic remains, or the interposition of laminae of clay. 

 Though this character is prevalent in the forest marble, yet it is not of uni- 

 versal occurrence, the beds being occasionally massive, and dividing only into 

 large irregular blocks. Strata of pale clay or sandy clay, in many localities, 

 separate the beds of shelly limestone, and vary in thickness from an inch to 

 three feet. 



5. The lowest division of the forest marble, the sand or sandy clay and 

 grit, does not invariably occur, and when present is often so thin as to escape 

 the notice of a hurried observer. The grit is calcareous, sometimes slightly 

 oolitic, of a pale brown or blue colour, and tolerably hard. It forms either 

 thin layers alternating with sandy clay, or large masses inclosed in loose sand. 



The following series of lists is given to illustrate the variations which take 

 place in the different groups of the forest marble. 



Right bank of the brook between Lullington and Woolverton, about three 

 miles to the north of Frome. 



Group 1. Clay, with lamina; of grit 8 feet. 



2. Quick sand, with concretions of grit 9 feet. 



Quarry between Lullington and the Factory. 



Group 1. Clay, with thin laminae of grit 8 feet. 



2. Irregular beds of sandstone, parted by layers of sandy clay. ... 10 feet. 



Kington Bottom near Kington St. Michael, about three miles to the north of 

 Chippenham. 



Cornbrash. 



Group 1. Clay 15 feet. 



2. Sand, containing large masses of calcareous grit, some of which 



are partially oolitic and shelly 9 feet. 



Beckington Quarry, in the Lane leading to Carpenter's Mill. 



Group 2. Sand, with large masses of grit containing fragments of wood . . 18 feet. 



Sandy clay 1 foot. 



/ Irregular beds of grit, separated by layers of sandy clay 5 feet. 



VOL. III. SECOND SERIES, 2 L 



