585 
4° and 9°. These facts will, I hope, enable you to under- 
stand that violent contortion without fracture of a rigid 
substance is a proof, not of an instantaneous force, but of 
slow and long- continued pressure. 
With reference to the lamination of the Lower Scar 
Limestone, which is little divided, and not noticeably 
bedded, where it lies horizontal, but almost schistose in its 
character at Lothersdale, Thornton, and Skipton, I may 
mention a little circumstance which leads me to attribute 
this difference to the bending of the strata. I was lately 
examining the Mountain Limestone of the Great Orrne's 
Head, and again and again I found that an apparently solid 
and homogeneous bed became divided into two, three, or 
twenty regular seams, according to the amount of flexure. 
This was known to the quarriers, who always worked in 
the more disturbed portions of the hill in order to get their 
stone more readily. 
The principal subterranean movements which have affected 
the Carboniferous strata of the British isles appear to have 
taken place at two distinct periods. It is interesting to 
observe that each system of disturbance had a tolerably 
constant direction, and that the parallel axis of the latter 
elevation are nearly at right angles to the former. "Taking 
the counties of Wicklow, Wexford, and Waterford, we see 
that the strike of the older line of rolls or upheaval, though 
often modified, the result of pressure upon the then existing 
stratified mass, is about N.N.E. and S.S. W. ; while the second 
movement, forcing the Old Eed Sandstone and Carboniferous 
Limestone into huge ridges and furrows, especially on the 
South of Ireland (including the older and previously 
upturned rocks, as well as the covering of these two rocks 
above them) is marked by east and west lines. Any 
good geological map of the British Islands will shew that 
these great east and west lines are continued, though on 
