Mineralogy and Geology. 113 
_» In Devonshire he establishes two lines of vertical cleavage, sixty 
miles apart, one at Stoke Fleming the other at Bickington; and they. 
bound a broad area over which the cleavage planes undulate in low 
flat waves, the axes of which bea is 
between E. and E.N.E. The an- bs 
nexed cut represents the relation of ee 
the planes of bedding and cleavage 
in these undulations near Launces- 
town and on the coast near Tintagel. The continuous lines represent 
the bedding and the dotted lines the cleavage. After stating other sim- 
ilar facts from different districts in England, Mr. Sharpe remarks as 
follows, with regard to the relation of the cleavage planes to the bed- 
ding in Devonshire :-— 
“Throughout the central area where the cleavage is nearly horizontal, the beds 
undulate in a succession of waves already described without offering any marked 
ures. 
the vertical line of cleavage passes, the beds are most violently contorted. Beyon 
this line is low ground at Barnstaple, in the band between the two lines of vertical 
portant memoir, of which a brief abstract 
4. Geological Society of London, April 
read, entitled, ‘On the Structure and probab F 
of the James river, near Richmond, Virginia ; by 
F.RS., V.P.G.S. 
Szconp Series, Vol. IV, No. 10.—July, 1947. 
h 
14th, 1847.—A. paper was 
le Age of the Coal Field 
Cuar.es LYELL, 
15 
