Part of Gloucestershire and Somersetshire. 33b 



Nearer toward the escarpment on the west^ the stratified beds contain con- 

 tinuous limestone some fathoms in thickness ; and thin beds of magnesian 

 limestone also appear. 



§ 14. Descending by the left bank of the Avon, no continuous rock be- 

 comes visible until we reach the trap of Avening green ; from whence, flanked 

 on both sides by the stratified beds, it may be followed with little interruption to 

 Daniel's wood on the north-west, in which quarter it partly consists of amor- 

 phous basalt ; its average breadth appearing to be about 40 fathoms. On the 

 north-eastern side the trap is evidently superior to the stratified beds, which 

 may be traversed uninterruptedly from Damory bridge up to the trap, dipping 

 at an angle of 20° to the south, 30° west. 



If, pursuing the relations of this body of trap, we descend from the top of 

 Daniel's wood to Cinderford bridge, we observe, 



1 . Trap ; then a little below. 



2. Sandstone, 10 or 15 fathoms wide, indistinctly displayed : this contains 

 calcareous casts of shells. 



3. Trap, a considerable way down the hill. 



4. Sandstone, sometimes approaching to hornstone, with some limestone, 

 the whole apparently two or three fathoms wide. 



into hornstone, by the heat which emanated from the trap when in a state of fusion. But in the 

 present case it may be objected to this view of the subject : 1. That both the hornstone and trap 

 are in immediate association and contact with beds of soft clay, marly clay, and granular sand- 

 stone ; while on the other hand beds of hornstone are found throughout the stratified series, and 

 in some instances far removed from the vicinity of trap. 2. The organic remains contained in the 

 layers and fissures connected with the upper surface of the bed of trap, seem to prove that in 

 this instance the deposition of the latter preceded the former. 3. Viewing the regular arrange- 

 ment which prevails in general throughout the transition formations of this district, both in range 

 and dip, it is evident that the trap constitutes discontinuous beds included in and parallel to the 

 continuous series of the stratified transition beds ; much in the same manner in which disconti- 

 nuous beds of other rocks appear in other formations ; as of quartz-rock in clay-slate, of lime- 

 stone in transition clay.slate, of gypsum in magnesian limestone, of rock-salt in new red sand- 

 stone. If any one of these be of simultaneous origin with the formation in which it is inclosed, 

 it may fairly be inferred that the others are so likewise : and these formations being undeniably 

 aqueous products, I do not perceive how we can avoid extending the same origin to trap also 

 when found under similar circumstances ; a view that is confirmed by the latter containing con- 

 temporaneous veins of calcareous spar and brown-spar, similar to those which occur in the conti- 

 guous transition sandstone and limestone. And the same may be said of all the formations of 

 trap that constitute portions of particular series in the primary and older secondary epochs, in 

 which I can perceive no proof of an origin posterior to that of the series of which they respect- 

 ively form a part. 



VOL. VI. 2 X 



