$4 PHILOSOPHICAL TRANSACTIONS. [aNNO 1684. 



were a continued wold of chalk and flint. What difference there is between 

 the wolds mountain sand, and that of the northern mountains, will best appear 

 in the table. Now the nakedness of the wolds is from the smallness of its sand, 

 which readily yielded not only to the rain that fell but to the wind also. Which 

 is evident from that vast tract of sandy hills which bound the coasts of France, 

 Flanders, and Holland, and which have made their coasts so shallow in respect 

 of ours, as being in great part blown off the Yorkshire, Lincolnshire, Suffolk, 

 or Essex, and Kentish wolds, and wrapped up upon their coasts; and the rea- 

 son of this is partly from the more constant westerly winds blowing over from 

 our coasts, and also of the meeting of the two tides, viz. that of the Channel, 

 and that other of north flood upon their coasts. 



I am well aware, that the finding of cockles or shells, as most writers are 

 pleased to call them, upon mountains, and sand also there, is by the same He- 

 rodotus used as an argument of a great deluge or inundation of waters; but as 

 I have elsewhere, I think, demonstrated, that the rock cochlites are no shells^ 

 so neither can I grant that the sand was adventitious to the mountains, but na- 

 turally originated there ; for that it is there plainly to be found some loose and 

 the rest in beds yet unloosened ; as I could name very many places, for instance, 

 Silden and Thorpe Fells, in Craven, this mountain sand is a white and transpa- 

 rent pebble, and some of it is small and easily swept and blown away, so is there 

 much of it upon the high mountains mixed with white pebbles of greater size. 

 It is the character of this sand not to yield to fire, as flint will do; and 

 though it agree with that and some other metals to strike fire from steel, yet it 

 does not calcine, as flint will be brought to do. And therefore this sand is the 

 true tarso of the Italian mountains, of which the fine Venetian glass is made; 

 and for this reason, the flint glasses were here in England ill compounded, the 

 foreigners mistaking the materials, which yet our country affords in plenty all 

 over the northern, and, I doubt not, the western mountains too. I have seen 

 from the Scotch mountains very excellent and large. 

 A Table of Sand, drawn up about Ten Years since ; such chiefly as I have found 



in the Northern Parts of England. 

 Sharp or rag sand, composed of small transparent pebbles, naturally found upon 



the mountains, not calcinable. 

 Fine. — White; Stitneham Moor in the road washed up very white pebble. 

 Flamborough head, of which the light house there is cemented. Calice 

 sand, burns reddish, but falls not in water. — Grey, Seaton banks near 

 Hartlepool or the Tees mouth, Escrick, in the gravel-pit there. — Reddish', 

 The pillow sand in the Baltic. — Brown; In a spring at Heshington. The 

 sand at the bath in Somersetshire. 



