18 
yet fully determined, but such as occur in Airedale are 
certainly newer than the Bala limestone, on which they rest, 
apparently unconformably, at Horton in Eibblesdale, and 
Southwaite near Austwick. The Airedale sections are too 
limited to be of any Yalue, except as indications of the course 
of the fault ; they occur only at Gordale and at Capon Hall, 
where on the watershed the slates contain beds of tough blue 
crystalline sandstone. The general dip is S.S.W., so that 
the lowest beds occur under the Tarn, and the highest on the 
watershed near Capon Hall. The direction of the cleavage 
is the same, but the angle is rarely that of the dip. I may 
remark here that this extension of the Silurian area of 
Eibblesdale as far east as Gordale Beck is not shown in any 
geological map yet published. 
The base of the Carboniferous series consists generally of 
limestone, crowded with pebbles, mostly of Silurian rocks, 
and varying according to the nature of the strata immediately 
underlying them. Occasionally we find, beneath this lime- 
stone-conglomerate, a mass of sandstone, some parts of which 
are also full of Silurian pebbles, often softer from decomposi- 
tion than the calcareous sandstone which forms the matrix. 
This latter deposit is well seen at Capon Hall, nearly fifteen 
feet in thickness, underlying the pebbly limestone conform- 
ably. (In this locality I found the cast of an Encrinite-stem, 
about half-an-inch long, encrusted with calc-spar.) Similar 
sandstone also occurs in Gordale Beck, and again in a gorge 
about a mile and a quarter east of Gordale. 
The typical Carboniferous, or Scar Limestone, is too well 
known to require much description. It is a mass of pure, or 
very nearly pure, limestone, from 600 to 1,000 feet in thick- 
ness, composed entirely of organic debris. This is its 
character both at Settle and in Derbyshire, but as if to show 
the value of the artificial divisions of the Carboniferous 
system which scientific men have adopted, it is represented 
