TATE ON THE GEOLOGT OF BEADNELL. 



63 



Productus giganteiis and other commoner mountain-limestone fossils^ it 

 abounds with large masses of the corals Lithostrotion hasaltiforme and 

 ChcEtetes septosus ; and occasionally we find Syringopora ramidosa, 

 which is a rare coral in the Northumberland beds. These distinctive 

 organisms are excellent guides in tracing the range of this "sill." 

 Northward I have found it at Holy Island, and southward I have 

 traced it to Spittleford, near Embleton, and to Dunstan, Craster, and 

 Shilbottle ; thence in a south-west direction to Whittle, Newton-on- 

 the-Moor, Framlington, and across the Coquet to Ward's Hill and 

 Rothley. It should be noticed that the magnesian character of this 

 limestone is a local phenomenon, seemingly in some way arising from 

 the proximity of basalt ; in several parts of its range, as at Shilbottle 

 and Framlington, it is a comparatively pure carbonate of lime. 



There are eighteen different coal-seams in the section ; most of them 

 thin and of an inferior quality ; only two exceeding 2 feet in thick- 

 ness; their aggregate thickness being only 24 feet 4 inches. That 

 which is called the Beadnell-coal" (No. 35) has been worked both 

 for domestic use and for lime-burning. It is of variable thickness, 

 seldom less than 2 feet 6 inches, and generally about 3 feet ; but on 

 Mrs. Taylor's estate it has been found as much as 6 feet thick, and of 

 a better quality than in other localities. It lies there, however, below 

 the sea -level ; and as the sea some time ago broke into a neighbouring 

 colliery, due precautions would be necessary to prevent a similar 

 irruption, in the event of this more valuable portion being worked for 

 the use of the district. 



The sandstones and shales associated with the coal-seams contain 

 relics of the vegetation of the Carboniferous Era ; Stigmaria jicoides 

 appear abundantly in these beds, with a few Sigillarise. One interesting 

 specimen of Sigillaria, laid bare in quarrying the sandstone in 1853, 

 deserves a more particular notice ; although but a fragment, it was 

 six feet in height, two feet two inches in diameter at the lower end, 

 and one foot nine inches at the higher. It stood perpendicular to the 

 strata, which dip 15° south-east, and its inclination to the horizon was 

 75°. The lower extremity terminated abruptly on the surface of slaty 

 sandstone beds, but the outcrop of the rock in which it was embedded 

 prevented our knowing how far upward it extended. Over its surface 

 was a thin carbonaceous coating, being the bark converted into coal ; 



