143 DESCRIPTION OF THE STRATA. 



the shells imbedded in it have served to augment. Sometimes there 

 is so much lime in the shale, that it readily effervesces with acids. 

 There are some instances, however, in which these crusts, or part- 

 ings, may be said to consist of sandstone, ironstone, or limestone, 

 rather than of indui*ated shale; as we may see in some of the Redcar 

 rocks, where we find an immense number of shelving beds succeed- 

 ing one another, each having its indurated surface or covering. In the 

 beds forming the scar, opposite the alum works of Stoupe Brow and 

 Peak, belonging also to the lowest part of the aluminous strata, we 

 find a number of successive courses of shale, some of which are 

 covered with considerable crusts of limestone, ironstone, or sand- 

 stone. 



Nodules of pyritous limestone are as common in the lowest shale, 

 as in the main bed of alum rock. They are generally small and often 

 nearly globular, resembling cannon balls. Sometimes we meet with 

 two connected together by a slender bar, like a double shot. The 

 pyritous balls of Huntcliff" have been celebrated since the days of 

 Drayton.* Most of them contain organic remains, which are also 

 plentifully distributed throughout the shale. The nodules are some- 

 times arranged in partial rows ; but more frequently occur in a 

 detached form. 



Such are the different beds belonging to the aluminous series. 

 In closing our description of them, it may be proper to remark, that 

 while they preserve nearly the same order throughout the alum hills, 



* The Rocks by Moultgrave too, my glories forth to set. 

 Out of their cranied Cleeves, can give you perfect Jet, 

 And upon Huntclip nab, you every where may find, 

 (As though nice Nature lov'd to vary in this iiind) 

 Stones of a Spherick forme of sundry Mickles fram'd, 

 That well they Globes of stone, or bullets might be nam'd. 

 For any ordnance tit ; which broke with Hammers blowes. 

 Doe headlesse Snakes of stone, within their Rounds enclose. 



Drayton's Poly-olbion. 



