BRITISH ASSOCIATION" MEETING AT NEWCASTLE. 



369 



interesting lists and parallels of fossils prepared by Mr. Salter for the two 

 last numbers of the ' Iron Ores of Great Britain,' in the memoirs of the 

 Geological Survey. The rich stores obtained by zealous collectors in 

 South Wales, and yielded by the productive strata of the Potteries' coal- 

 field, have been formed under his careful hands into a very valuable foun- 

 dation, upon which I hope that we may soon see in course of erection a 

 systematic and comparative natural history of the British coal-fields. 



On Coke, Coal, and Coal Mining in Northumberland and Dur- 

 ham. By Messrs. Wood, J, Taylor, and J. Marley. — The Northern Insti- 

 tute of Mining Engineers will publish this paper, with several illustrations. 



On the Fossil Teeth of Horse found in Bed Clay at Stockton. 

 By Mr. J. Hogg. — As many human bones had been dug up in the same 

 field, it was supposed that a battle had been fought there, and that horses 

 and riders had been interred together. 



Magnesian Limestone of the County of Durham. By Messrs. 

 Forster and J. Daglish. — As the magnesian limestone covered a conside- 

 rable portion of the northern coal-field, its study was most interesting to 

 those engaged in the mining operations of the district. This arose from 

 its important bearing, not only in geological, but also in physical condi- 

 tions. Of the latter, one of the most marked was the large quantity of 

 water met with in shafts that had been sunk through the limestone for the 

 purpose of winning the coal below. In all sinkings through magnesian 

 limestone there were feeders of water, chiefly from gullets and fissures, 

 and if the shaft were not drained the water rose to a point which generally 

 remained constant. Although the line commenced at the sea-level, it nei- 

 ther continued in this plane nor followed the line of stratification nor the 

 undulations of the surface, but rose almost uniformly with the surface as 

 it passed inland. At Seaton Pit it is 226 feet from the surface, and at 

 Hetton, 3^ miles directly west, it is 108 feet ; and as the surface-level of 

 the latter is 90 feet above that of the former, it follows that the line of sa- 

 turation rises in this direction at the rate of 60 feet per mile. There is a 

 curious anomaly in the case of North Seaton and Cambois Pits. The cir- 

 cumstances which favour the remarkable accumulation of water in the 

 limestone, and the rapidity with which it is drained off into pits sunk 

 through it, is due to several causes, some of which are peculiar to this for- 

 mation, and perhaps to this district. They are — 1st. The arrangement of 

 the beds of stratification ; 2nd. The contour of the country ; 3rd. The per- 

 meability to water of this formation. The beds of stratification dip to- 

 wards the sea at an angle somewhat more inclined than the surface of the 

 ground, so that on this line of section the magnesian limestone crops out 

 with a bold escarpment, about 3| miles inland from the sea, forming one 

 of the most pleasing features in the landscape of the south-east portion of 

 Durham, An observer standing on the escarpment, and looking inland, 

 would have an extended view over the wide expanse of flat country, which, 

 owing to the softer character of the rocks of the coal-measures, always lies 

 at its base, and ever running up into the limestone in deep bays or fiords, 

 gives it the character of an ancient rugged coast-line. Seaward an entirely 

 different aspect is presented, a series of undulating hills, intersected with 

 many deeply-cut picturesque and beautiful ravines, which being low and 

 sheltered are well wooded and clothed with a luxuriant foliage. The bold- 

 ness of this escarpment is, no doubt, to a certain extent due to the soft na- 

 .ture of the "yellow sand" lying immediately below it; this sometimes 

 reaching a thickness of 50 feet, extends over the flat base to a considerable 

 extent beyond the limestone, and, being thoroughly pervious to water, 

 forms a natural absorbent for all the drainage of the district round, which 



VOL. VI, 3 B 



