240 
does the general mean indicate a drifting from near North, 
but the number of cases, included between North-East and 
North- West, is five times as many as in an equal portion of 
any other part of the compass, and those North of East and 
West are nine times as numerous as those South. We may, 
therefore, conclude that the general direction of the drifting 
in the coal field about Edinburgh is mainly from North-East 
to North- West, only slightly interfered with by a southern 
drift. 
I have examined the arrangement of these means, with a 
view to ascertain whether any definite connexion could be 
traced between their direction and position on the map, and, 
although I have detected some kind of a law, yet I forbear 
to describe it, not having explored sufficiently wide a tract 
to test its accuracy. My chief object on the present occasion 
is to show what may be made out by carefully studying the 
drift structure of sandstones, and I shall not further enter 
into the subject at present ; for, being occupied in tracing 
the beds, and ascertaining the directions of the currents, 
over a space of about sixty square miles, in the neighbour- 
hood of Sheffield, I have ascertained several facts of con- 
siderable importance in the theory of the formation of the 
coal strata. When these researches are concluded, I shall 
probably lay them before this society, together with an 
outline of such general conclusions as they appear to 
indicate. 
ON CERTAIN CAVITIES IN THE LIMESTONE DISTRICT OF 
CRAVEN. BY MR. THEODORE W T EST. 
Having lately been on a Geological ramble in the neighbour- 
hood of Skipton, my attention was particularly drawn to 
certain cavities or hollows in that part of the district known 
as Appletreewick Moor. These hollows run in a pretty 
