3G0 
THE GEOLOGIST. 
The saddle-beds arc recurrent tliroiigli the wliole tliickncss of the 
limestone series, and, at least, five sets of these beds arc distingiaishcd 
in the ncighboui'hood of Alstonfield ; but, no certainty belongs to 
this enumeration, inasmuch as the same strata are plicated in certain 
parts and not in others. The saddle-beds are known to crop out at 
the surfoce, and a cliie is thereby afforded to and embraced by the 
miner in searching for them below ; but it has been particulai'Iy re- 
marked that the contortions ai'e always more gentle above than in 
depth, resolving themselves, generally, into a long swell very dif- 
ferent from the rapid and closely associated folds of the same beds as 
seen below the surface. In fig. 3 the dotted lines, x, y, z, represent 
this gradual dying out of the folds of the beds a a at their crop a' a' ; 
but I shall have presently occasion to refer again to this curious cir- 
Lign. 2. — Contorted beds of altematinfr limestone and shnlc strata, showing the formation of 
" saddles" and " saddle-joints." 
cumstance. The breadth of the saddles from wing to wing, taken 
midway above the trough, of course, varies greatly, but there is 
something like an average, and which may be stated at forty feet. 
The joints, both huckle and trough, mn very regularly ; and it is 
worthy of remark that they are always continued out of the beds 
either above or below. Their general direction is north-north-west 
and south-south-east, which is also the direction of the joints, in a 
large majority of cases, of the Mountain-limestone, in Derbyshire 
and Staffordshire. The perpendicularity of the saddles themselves 
on their line of strike (east and west) is a matter of some importance, 
since by the way in which they are inclined so may the direction of 
the maximum compressing force be ascertained : thus if the majority 
of the saddles bear to the right, it is more than probable that the 
greatest resistance was to the left, and that the force, whatever it 
