GEOLOGY. 37 



In the Howardian tract this series forms a narrow terrace 

 which extends from the hollow along which the York and Malton 

 Railway runs to the Derwent at Crambeck, its beds sloping 

 towards the east and north-east. The highest part of the ridge 

 is towards the north-west, where it attains an elevation of 

 upwards of 500 feet. At Crambeck, near Castle Howard 

 station, the Millepore series is shown 60 feet above the 8 feet of 

 Dogger, with Ironstone. It can be traced hither from Hood 

 Hill, Coxwold and Owlston and is best seen in the neighbour- 

 hood of Brandsby and Terrington. The most noteworthy 

 feature which the series, in this part of its course, presents is this 

 development of the Millepore Oolite, which is well exposed in 

 the quarries above Castle Howard station, and a corresponding 

 change in the central calcareous bed, which here assumes an 

 aspect of more decided difference than heretofore as compared 

 with the sandstones which surround it. It becomes slaty and 

 fissile and is separated from the Millepore Oolite by sandstone 

 and blue clay. There is also a cap of this series over the Lias 

 in the hill at Craike near Easingwold and in the Vale of Mowbray 

 at the south end of Cotclifife wood. 



The Cleveland Basaltic Dyke. — This is a remarkable dyke of 

 dark-coloured basaltic rock, nearly vertical in position, generally 

 about 60 feet in horizontal thickness, which, although in some 

 places not exposed at the surface, can be traced with tolerable 

 certainty from within four miles of the sea, six miles S. of 

 Whitby, by way of Goathland dale and Eskdale to Great Ayton 

 and Stainton, across the Tees to Cockfield Fell in Durham and 

 actually on across the Eden valley at Armathwaite, a distance of 

 more than 90 miles in a W.N.W. direction. * The strata which 

 it penetrates are, in Durham the Mountain Limestone, the Mill- 

 stone Grit and the Coal Measures ; in North Yorkshire the New 

 Red Sandstone, the Lias and the Lower Oolite. By some 

 geologists it is supposed to be connected with the Teesdale 



* See Q. J. G. S., xl. 212 ; also Woodward's Geol. England and 

 Wales, p. 570. 



Feb. 1888. 



