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railway cutting, on the slope of a hill, the reddish-brown clay 
is very compact, and full of angular, as well as rounded stones. 
Near to where this cutting joins the old line of railway the 
reddish-brown clay overlies the blue clay, with a very distinct 
line of demarcation between them. Between Long Preston 
and Skipton, the part of the plain of Craven traversed by the 
railway consists of a very remarkable series of knolls vary- 
ing from a few yards to at least 200 feet in height. The 
outline of these knolls, which is very curvilinear, is owing to 
the extent to which they are made up of drift. The Yoredale 
strata of the plain of Craven rise up to nearly, if not quite 
the highest, parts of these knolls in some places, and in most 
of the knolls there is probably a rocky projection which acted 
as a protector to a leeward tail of drift which formed a 
nucleus for a larger accumulation. In many places the whole 
height of a knoll, through which the railway has been cut, 
consists of drift, and as the drift (as shewn here and there by 
brook- sections) extends to a considerable depth below the 
level of the railway, we cannot resist the conclusion that in 
the plain of Craven the drift often reaches a thickness of at 
least 150 feet. The greater part of it, in the sections, 
appears to consist of yellow or reddish-brown boulder- clay, 
but a considerable part of it is blue clay. The stones in both 
clays are in general well rounded — indeed, often as much so 
as on any sea-shore. Both clays, but especially the blue clay, 
graduate into an unwashed, and unstratified or imperfectly- 
stratified, gravel, which in railway cuttings often looks like 
washed gravel, owing to rain w^ashing away the clay and 
leaving the stones. The drifts, of the plain of Craven have 
no connection with any river. They are most typically 
developed on the watershed part of the plain which lies 
between the courses of the Eibble and the Aire. To the 
north, north-west, east, and south of Skipton, we find knolls 
of drift similar to those above described. The EUer Brook 
