340 Mr. Horner on the Geology of the 



with a gradual fall to the alluvial land on the banks of the rivers 

 Parret and Tone. On the western side of the Quantock hills the 

 descent is very rapid into the valley ; on the eastern side it is in ge- 

 neral much less so, and a great many lateral branches stretch out 

 at right angles to the range, shooting off, however, considerably 

 below the summit. These sometimes terminate at a very short dis- 

 tance from the central ridge with an abrupt slope, at other times 

 they descend very gradually almost to the Parret, shewing occasion- 

 ally at their termination their identity in composition with the 

 central mass. 



The whole of the mountainous country I have mentioned has a 

 smooth undulating and rounded outline, no where rugged or pre- 

 senting any cliffs or precipitous faces, except on the sea shore, 

 where sections have been formed probably by the action of the 

 tides. The whole country is so covered by vegetation, either in 

 the form of heath and turf on the high land, or of the more luxu- 

 riant productions of the vallies, that very few opportunities occur in 

 the interior of ascertaining the nature of the rock on which the soil 

 rests ; but the cliffs on the sea shore afford such an ample field for 

 studying the mineralogical structure of the countr}% that the scat- 

 tered observations in quarries, may be more strongly relied on and 

 more easily connected. 



§ 3. From the Parret to Barnstaple Bay there is no river of any 

 magnitude : the great watershed is to the south, and the Ex, one of the 

 most considerable of those rivers which fall into the English Channel, 

 rises in Exmoor Forest. The southern shore of this part of the Bristol 

 Channel is very steep, the sea in many parts not leaving the cliffs 

 in the lowest tides. From Minehead Point westward, the charts 

 give 8, 9, and 10 fathoms water close in with the shore. East- 

 ward of that point the coast is more fiat, and towards the mouth of 



