BLUE LIMESTONE. 105 



spots, the footpath from Whitby to Sneaton crosses the limestone, at 

 a small stream which flows through the ravine into Shalmrigg beck, 

 as does also the stream running through the other ravine, a little to 

 the west. 



Towards the western extremity of this chain, the limestone beds 

 are found cropping out near Swainby, in the south-west bank of Scug- 

 dale, at a great elevation. Here the limestone is about 15 feet thick; 

 a bed of shale, 12 feet thick, lies immediately over it; and above 

 that the sandstone beds rise to a considerable height. In the front 

 of Coldmoor and of the Wain-stones hill, the blue limestone crops 

 out at a much greater elevation. In the central parts of this range, to- 

 wards Burton Head and Ralph Cross, it has not been detected; but 

 there can be little doubt of its existing there, concealed by the allu- 

 vium; especially as it is found towards the centre of the second chain 

 of alum hills, on the north-east side of Commondale, about two miles 

 to the south-west of Danby or Castleton coal-pits. To what extent 

 the blue limestone is continued in the rest of the second chain, has 

 not been ascertained; but its limits cannot be very extensive, for it is 

 not found in the strata along the shore, and ia several of the western 

 hills of this chain, as well as in those of the third chain of alum hills, 

 the aluminous beds rise too near the surface, to admit its existence 

 above them. 



As these limestone beds occupy a high position in the alum hills, 

 so we have evidence that they run under the highest of the oolite 

 hills; for they appear in some of the valleys immediately beyond 

 them. This is particularly the case at Sutton-imder-Whitestone-cliff, 

 on the north side of Hood hill; where we find in the plain, the same 

 blue limestone that crops out in the fronts of the Cleveland hills, 

 though somewhat different in its qualities. The blue and grey lime- 

 stone at Coxwold appears to belong to the same beds. 



2d 



