96 DESCRIPTION OF THE STRATA. 



considerable minuteness, nothing corresponding with this ironstone 

 could be found ; though the next member of the strata is there very 

 conspicuous. Nor have the hard beds been fully identified in any of 

 the inland heights, though some resembling them are observed in 

 various spots. A bed of calcareous ironstone, containing shells, very 

 like the ironstone beds at the Gristhorp shore and the White Nab, 

 was found by the authors, on the east side of Newton Dale, north- 

 east from the village of Newton; and, from its position in the strata, 

 this bed may be presumed to be the continuation of the same iron- 

 stone; but the beds in Newton Dale, and other inland places, differ 

 so greatly from those on the coast, that it is no easy matter to trace 

 the correspondence between them. The difficulty, in this instance, 

 is increased by the number and variety of the ironstone beds, occurring 

 among the inferior beds of sandstone and shale. 



Instead, therefore, of attempting to pursue this member of the 

 strata any further, we pass on to the next, viz. 



THE BLUE LIMESTONE. 



On reaching this part of our strata, we take our final leave of the 

 oolite hills : for, though several of the beds which are now to be 

 described, are known to run under these hills, and form their basis; 

 yet they hold a conspicuous place in the higher parts of the next 

 range of hills, to which therefore they ought to be appropriated. 



The hills belonging to the northern part of our district, from the 

 oolite range to the banks of the Tees, are all of one character: the 

 upper part of them consisting chiefly of sandstone, sandy shale, bitu- 

 minous shale, and coal; with some limestone and ironstone beds; 

 the lower, which is commonly the principal part, consisting of the 

 great beds of aluminous schistus, and the various seams that are inter- 

 stratified with them. From the occurrence of coal in these hills, some 



