124 Notes on the Geology of Gorhridge. By G. A. Lebour. 



given the name of Upper Bernician. Thin limestones separated 

 from each other by thick grits and sandstones, shales, and coals 

 are the characteristics of this formation. The conditions under 

 which its various members were deposited therefore varied from 

 those of land-surfaces of much smaller area and shorter duration 

 than those of the later Coal Measure times, to those of sandy 

 shelving sea-shores, shallow muddy estuaries, and deeper (but 

 not ver^ deep) sea-bottoms abounding in the sea-life of coral 

 regions. The wreck of this fauna it preserved to us in the shape of 

 beds of calcareous rock almost entirely made up of the hard parts 

 of the creatures then living, entire or in fragments, encrinites, 

 brachiopod shells (and especially those belonging to the genus 

 Froductus), branching compound corals (such as Lithostrotion 

 junceum and other species of the same genus), and foraminifera, 

 predominating. It is worth noting that the last-named, so often 

 regarded as almost the only organic limestone makers, although 

 common enough when carefully sought for in the Bernician 

 limestones of Northumberland, are yet quite of secondary import- 

 ance as rock builders here, when compared with the more bulky 

 organisms before alluded to. On the whole, then, the long Ber- 

 nician period, represented in some parts of this County by more 

 than 8,000 feet of numberless alternations of strata, was evidently 

 one of incessant oscillation, land succeeding sea and sea land, 

 again and again without intermission. 



Taking (as is most convenient to do) the uppermost bed of 

 limestone as the upper limit of the Series within the boundaries 

 of the tract described, we have the following easily determined 

 Limestones to which we may look for lines subdividing the 

 Series in a useful manner. They are in descending order : — 

 The Felltop Limestone No 4 Limestone 



No 2 Limestone The Little Limestone 



No 3 Limestone The Great Limestone 



Of the above The Felltop, Little, and Great Limestones are 

 practically continuous across the County from Alston to the sea. 

 The first-mentioned is well seen in the bed of the river at the 

 sudden bend half a mile east of Styford Hall. It is full of 

 fossils here, and it is remarkable that these are as a rule 

 different from those which characterize the bed at Harlow 

 HiU. They agree, however, with the faunula of the same 

 horizon at Foxton HaU near Alnmouth, of which I gave 

 a description some years ago in these Transactions. Nos 2, 



