364 Mr. Weaver's Geological Observations on 



general one, two^ and three feet thick; and they are separated by thin irregular 

 layers of clay, from half an inch to one and two inches in thickness. Some of 

 the beds of clay^ however^ extend to one, two, and three feet in thickness ; 

 and being- much charged with particles of yellow ochre, they are wrought for 

 the sake of that substance, from which a pigment is prepared, by means of pits 

 sunk two or three fathoms in depth. The sandstone consists of the following 

 varieties : — 



1. Yellowish, grayish, and reddish white, minute-granular sandstone; 

 composed of particles of quartz closely aggregated. This passes into 



2. Compact quartzy sandstone^ or quartzy rock, of similar colours ; and this 

 into 



3. Compact splintery hornstone, pale blueish and yellowish gray, grayish 

 and yellowish white. 



4. A siliceous breccia, composed of small fragments of sandstone, with dif- 

 ferently coloured pieces of hornstone and quartz, and grains of felspar ; in a 

 specimen of which I found an entrochite, consisting of siliceous matter. I 

 have observed this compound firmly adherent to the fine-grained yellowish 

 white sandstone. No. 1, and in a parallel position ; the different members of this 

 series being probably interstratified with each other. But the prevailing cha- 

 racter of the rock is that of quartzy sandstone or quartz-rock, and horn- 

 stone ; while in the brow of the hill above East and West Harptree, may also 

 be observed masses of a siliceous conglomerate ; abase of hornstone enveloping 

 fragments of quartzy sandstone and hornstone *. 



3. Yellowish and ash gray porous fine-grained sandstone, composed of 

 grains of quartz, with a few scattered minute spangles of silvery mica. 



6. The preceding sandstone, more or less charged with carbonate of lime, 

 passing into a sandy limestone^ and sometimes of a friable consistence. 



7. Dull compact limestone, containing a few sandy particles and scales of 

 silvery mica ; and sometimes exhibiting minute dendritic delineations. 



In the sandstones No. 1. and 2. casts and impressions of shells occur; which, 

 though often obscure, are referable to a species of ammonite, a turbinated 

 shell, the Pecten quinquecostatus, a Modiola, a Pinna, an Astarte or Venus, and 

 one or two species of Ostrea, Of these the casts of the Astarte, and the im- 

 pressions of the Modiola, are the most common. Crinoidal remains also occa- 

 sionally appear under the same circumstances. 



In the sandstones No. 5. and 6., impressions and partial casts of a species 



* Some of the Druidical stones at Stanton Drew consist of the conglomerate No. 4 ; while 

 others are composed of No. 5. 



