838 Proceedings of the British Association. 



ness, and occupying a well defined zone in North Devon, its upper 

 bed alternating with and gradually passing into a great deposit of 

 sandstones of various colours and micaceous flagstones. These si- 

 liceous masses alternate with incoherent slates, and are in some 

 places surmounted by great masses of red unctuous shale, which, 

 when in a more solid form, generally exhibit cleavage oblique to 

 the stratification. — 5. The Silurian system resting conformably on 

 the preceding, and of great thickness, on the north- w^estern coast, 

 containing many subordinate beds and masses of limestone. In its 

 range towards the eastern part of the county, it gradually thins off, 

 but its characters are well preserved, and it everywhere contains 

 vast numbers of characteristic organic remains. — 6. The carbona- 

 ceous system of Devonshire, in a direction east and west across the 

 county, in its southern boundary so close to Dartmoor that its lower 

 beds have been tilted up and altered by the granite. It occupies 

 a trough, the northern border of which rests, partly in a conformable 

 position upon the Silurian system, and partly upon older rocks, 

 probably of the division No. 4. Its southern border also rests on 

 the slate rocks of Launceston. It everywhere exhibits a succes- 

 sion of violent contortions. In some places it is overlaid by patches 

 of green sand, and west of Bideford by conglomerates of the new 

 red sandstone. The lowest portion of this vast deposit is general- 

 ly thin bedded, sometimes composed of sandstone and shale, with 

 impressions of plants, sometimes of indurated compact slate, con- 

 taining wavellite. These beds are surmounted by alternations of 

 shale and dark-coloured limestone with a few fossils. Subordinate 

 to these, there are on the western side of the county thin veins 

 and flakes of culm or anthracite ; but this is wanting on the eastern 

 side, and the calcareous beds are more expanded. The higher beds 

 of this deposit are well exhibited on the coast west of Bideford. 

 These often contain impressions of vegetables. Though in a state 

 of greater induration than the ordinary coal-measures of England, 

 and even in many places destitute of any trace of coal, still these 

 beds do not difl^er from the great unproductive coal-field of Pem- 

 brokeshire. The authors consequently concluded, that from the 

 order of superposition, — from mineral structure — from absence of 

 slaty cleavage peculiar to the older rocks on which this deposit rests, 

 and from the specific character of its organic remains, it may with- 

 out hesitation be referred to the regular carboniferous series. In 

 the course of the details, the authors alluded to a remarkable ele- 

 vated beach, occupying two miles of coast on the north side of 



