Geological Society, 477 



chiefly from Ihe inside of the larger vessels, as if they were coated 

 with an extremely thin layer of carbonate of lime. This fact, connected 

 with the medullary rays remaining in some instances unchanged, orbut 

 partially changed, presents, as stated by the author, the first ocular 

 demonstration of progressive steps in the process of petrifaction. The 

 communication concluded with some observations on the fossil wood 

 of Allesley described in Dr. Buckland's paper, in some of the specimens 

 of which there are spindle-shaped portions similar to those in the 

 partially petrified wood of Buckeberg. 



** Description of a Raised Beach in Barnstaple Bay, on the north- 

 west coast of Devonshire," by the Rev. Professor Sedgwick, F.G.S., 

 and Roderick Impey Murchison, Esq., F.G.S., was afterwards read. 



This raised beach is first seen at the northern extremity of the 

 blown sand-hills called Braunton Burrows, and thence may be traced 

 round the western end of Saunton Down, into Croyde Bay. i^fter 

 meeting with some interruptions it reappears, and may be followed to 

 the face of the bold headland called Baggy Point, about three miles 

 from the place of its commencement. In situations where it is best 

 exposed, especially on the south side of Saunton Down, it puts on 

 the form of a horizontal under terrace, resting upon an indented 

 and irregular surface of the older formations, and abutting against 

 their component beds. It forms regular sea-cliffs, the stratification of 

 which is most distinct ; and the several beds may be traced by small 

 bands of shingles, by alternating courses of different degrees of fine- 

 ness, and by horizontal lines of division. In distinctness of stratifica- 

 tion it yields to no rock 3 and as several parts of the cliff are in a state 

 of perfect induration, presenting regularly bedded masses of calcareous 

 grit and sandstone, the authors at first sight mistook it for a secondary 

 formation. 



The bottom of this horizontal deposit is chiefly composed of indu- 

 rated shingles resting on the ledges of the older rocks, and filling 

 up their inequalities. These conglomerates or shingles are seldom 

 of great thickness, but in some places alternate two or three times 

 with beds of sand, so as to reach an elevation of eight or nine feet in 

 the horizontal deposit. Over the shingles are horizontal beds of sand, 

 occasionally indurated, sometimes putting on a concretionary struc- 

 ture, and weathering into grotesque forms by the action of the ele- 

 ments. Lastly, the preceding deposits are surmounted by regular 

 beds of finely laminated sand in a state of imperfect induration, and 

 sometimes hardly differing from the sand of the actual beach between 

 the high and low water marks. The thickness of these beds of sand 

 amounts in some places to more than twenty feet. These marine 

 deposits are frequently covered by terrestrial overshot materials which 

 have descended from the higher talus of Saunton Downs. In the 

 whole of the stratified under clift' above described there are sea shells. 

 In the upper part they are rare, and in a bad state of peservation j 

 but in the lower and more indurated portions they are more abundant, 

 are often well preserved, sometimes appearing in beds, and in their 

 condition and arrangement exactly resembling the shells of a modern 

 beach. In species, they are identical with the living shells of the coast. 



