412 Mr. Hutton's Notes on the New Red Sandstone of 



having removed the whole of the yellow sand, except at the 

 south-eastern point, where the curved beds of limestone may 

 be again seen alternating with the sand, as well as in the cliff 

 below the Fisherman's Beacon*. 



From the appearances at this point it cannot be doubted that 

 the dyke has thrown down the magnesian limestone,asProfessor 

 Sedgwick observes ; and it also follows, as a matter of course, 

 that the limestone at Whitley Quarry, upon the course of the 

 dyke, is similarly affected. A close examination of the quarry 

 last autumn convinced me that such was the fact; the opera- 

 tions of the quarrymen had removed, in one spot, the whole 

 of the limestone, and laid bare, for a considerable distance, 

 the southern cheek of the dyke, which was here, as in the 

 Haven at Cullercoats, a bed of shale, having a hade or dip, at 

 a considerable angle, towards the north. On the southern 

 side of the quarry, in several places where the stone has been 

 worked near the line of the dyke, marks of mechanical action 

 are visible, particularly near the rail-way, on its eastern side. 



The general opinion is, that this patch of limestone over- 

 lies both edges of the dyke, and that it has been deposited not 

 only after the slip took place, but after the removal of the 

 whole of the high side, which would necessarily be left, by the 

 sinking down of the strata on the north. This is an opinion 

 from which I confess I differ with reluctance ; nevertheless, as 

 the limestone at Cullercoats is manifestly thrown down along 

 with the yellow sand, and contorted by mechanical action, we 

 are compelled to come to the conclusion, that the ninety-fathom 

 dyke was formed after the deposition and consolidation of the 

 magnesian limestone ; and this would necessarily be our con- 

 clusion if there were no marks in the quarry at Whitley to 

 point it out, as we cannot suppose the limestones in the two 

 situations to be of different ages, or, closely connected as they 

 are, to be operated upon by different causes. 



The idea of the limestone overlying the dyke, may possibly 

 have arisen from its being considered as a perpendicular fis- 

 sure, which it certainly is not, either in the quarry at Whitley, 

 at Cullercoats, or at Gosforth, where it has lately been so 

 completely examined in Mr. Brandling's new colliery. 



We have thus traced the edge of this formation through 

 the whole of the county of Durham, and to Cullercoats, in 

 Northumberland, its most northern limit ; and, in the whole 

 line, we have seen the yellow sand and red sandstone accom- 



* Iq Professor Sedgwick's Section (Geol. Trans. 2nd Series, vol. iii. pi. v. 

 fig. 2.) the yellow sand, thrown down by the dyke, is coloured as mag- 

 nesian limestone, which is a mistake, the limestone existing only in thin 

 beds, subordinate to the sand, which is here of great thickness. 



panying 



