lyo 



HARDWICKE'S SCIENCE-GOSSIP. 



wells in the city to a depth of over 70 feet below the 

 surface. The boulder clay with its accompanying sands 

 and gravels — in which some fine sections showing most 

 curious contortions were exhibited at the time the 

 new station was being built — is now unfortunately only 

 exposed in a few railway cuttings, and these are not 

 of any particular interest, so that we must pass to the 

 more recent deposits which are so well seen near 

 York. The warp, or lacustrine clays, with their inter- 

 vening sands, are exposed in several fine sections in 

 the numerous brickpits to the south and east of the 

 town ; they consist usually of two beds of clay with 

 an intervening bed of sand, the lower clay being 

 always finely laminated. 



York being thus situated between the two regions 

 of greatest geological interest, and at some consider- 

 able distance from either of them, it will best suit 

 our purpose, and also of those who wish to join the 

 excursions of the Association, to describe the two 

 districts separately. Firstly, the Palaeozoic forma- 

 tion, which comjirises the range of hills in the 

 western half of the county ; and secondly, the Meso- 

 zoic rocks, which include the moorlands of north-east 

 Yorkshire and the wolds in the East Riding. 



The first of these districts, which is entered at 



"Vf. Vi'tsttm Moorlands 



limestone proper, and in many cases when the cal- 

 careous matter has been exposed to air and moisture 

 has the appearance of pumicestone. 



The Millstone Grit, which next succeeds the 

 Yoredale beds, is also well seen in this neighbourhood, 

 the lowest portion (the Kinderscout) Grit occurs in 

 three separate beds, and is exposed in ,the railway 

 cutting to the south of the town and also in the 

 romantic hillside of Birk Crags ; but perhaps the 

 most peculiar outcrop of the rock is that at Almes 

 Cliff, some little distance to the south-west, where a 

 mass of the rock devoid of vegetation, stands up in 

 a very conspicuous manner above the surrounding 

 country. This curious rock may be seen from York, 

 and even from much greater distances, where it has 

 rather the appearance of a stumpy volcanic cone than 

 a grit escarpment. Above the Kinderscout Grit are 

 one or two beds known as Follifoot Grit ; they are 

 associated with a seam of coal, but are not of 

 particular note, although they underlie an interest- 

 ing little bed very full of fossils, an unusual circum- 

 stance in beds of Millstone Grit age. The Plumpton 

 Grit, the uppermost bed of the Millston Grit in this 

 district, is more largely developed than any of the 

 foregoing ; it is noted for the peculiar and fantastic 



VORK 



TheWoUs E. 





Fig. 99.— Diagram showing geology west to east across Yorkshire. 



about twelve miles from York, is composed almost 

 entirely of Carboniferous rocks, with a narrow belt of 

 Permian measures on its eastern margin. The Car- 

 boniferous rocks are divided into Carboniferous Lime- 

 stone, Yoredale Rocks, Millstone Grit, and Coal 

 Measures ; the Permian Measures include an upper 

 and a lower limestone, with two or three beds of j 

 marl associated with them. 



The lowest beds of the Carboniferous series lie 

 mostly to the north-west of the county and at too 

 great a distance from York to come within the scope 

 of this notice, although perhaps an excursion may be 

 arranged to visit the celebrated cliffs of Malham and 

 Gordale which have been produced by that laro-e 

 dislocation known as the Craven fault, the throw of 

 which is estimated to be under Ingleborough not less 

 than 3000 feet. 



The Yoredale beds maybe seen at Harrogate, where 

 they are brought up along an anticlinal axis ranging 

 north-east and south-west ; they consist principally 

 of shale with bands of cherty limestone associated 

 with a massive bed of grit. The limestone, which is 

 locally known as "roadstone," is a peculiar rock 

 containing the remains of Encrinites in great numbers, 

 the rock frequently being rather an aggregated mass 

 of the silicified skeletons of these creatures than a 



shapes which the weathering of the rock causes it to 

 assume. Plumpton Rocks andBrimham Crags are both 

 formed by this grit, and perhaps there are few excur- 

 sions to the north-west of York which will better 

 repay a visit from the Association than to these 

 romantic spots. At Knaresborough this grit crops 

 up in the bed of the river and is overlaid by the 

 Magnesian Limestone, the unconformable junction of 

 the two being well seen in the picturesque gorge 

 below the Castle. The grit is frequently of a reddish 

 colour, and was at one time thought to be the equiva- 

 lent of the Rothliegende of Germany, and consequently 

 to belong to the Permian formation. 



The Permian Measures consist of an upper and 

 lower bed of limestone with an intervening bed 

 of marl or soft sandstone, and occasionally an 

 upper marl over the top limestone, and also, al- 

 though very rarely, a third bed of marl below the 

 lower limestone. The Lower Limestone, however, 

 is the principal rock of the series, and forms a 

 narrow tract of country extending by Conisborough, 

 Pontefract and Knaresborough to the neighbourhood 

 of Ripon, which from its gentle undulating contour 

 and steep wooded banks is singularly beautiful. 



To the east of the Permian Measures we enter upon 

 the great vale formed by the Trias, which in the 



