﻿350 A. J. Jukes Broione — On the Tipper Greensand, etc. 



bold crags, marked by the Ordnance station, 1350 feet above the sea- 

 level ; here the beds end abruptly, being cut off by the Craven 

 fault. The position of this fault is also shown by the abrupt termi- 

 nation of similar grit crags at Fancarl, by great disturbances of the 

 beds at Thurskell Well, near Hebden, and by disturbed beds on the 

 banks of the Wharfe near Lyth House, whence the fault runs by 

 Skirethornes, with limestone on its north side and grit on its south, 

 to join the line of bold cliffs which mark the line of the fault from 

 Malham to Settle. East of the river Dibb we have, north of the 

 Craven fault, massive white limestone, dipping north at 19°, 

 closely overlain by the grit of Grimwith Fell, from which the main 

 mass of limestone is separated merely by a thin band of mixed 

 shales and limestones. The green mass of Greenhow Hill forms the 

 dome-shaped end of this band, which is in fact an anticlinal, broken 

 up by the Craven fault. Between the river Dibb and Grassington 

 the groimd is very obscure ; but the Millstone-grits seem to be 

 separated from the great limestone by a considerable thickness of 

 shales, with but poor limestone bands. At Grassington, however, 

 the limestones swell out, and with the exception of two bands of hard 

 sandstones, known as the Dirt Pot Grits, there is solid limestone 

 from the grits of Grassington Moor to the river Wharfe. North- 

 wards the limestone gradually breaks up, and finally takes on the 

 Yoredale type, so well known from the writings of Professor 

 Phillips. 



ni. — Notes on the Correlation of the Beds constituting the 

 Upper Greensand and Chloritio Marl. 



By A. J. Jukes Browne, B.A., F.G.S. ; 

 of H.M. Geological Survey. 



ONSIDEEABLE uncertainty has for some time existed with 

 regard to the formations known by the names of Upper Green- 

 sand and Chloritic Marl. 



The series of beds which are thus denominated have been accurately 

 described as they exist in several different localities, and the strata 

 supposed to constitute these divisions have been shown to vary greatly 

 both as regards their lithologicil characters and their fossil contents; 

 but very few attempts have been made to ascertain the lateral ex- 

 tension and the exact stratigraphical relations of these component 

 beds ; they have been like the fragments of a puzzle which no one 

 has succeeded in putting together. 



Geologists, indeed, were for a long time contented to receive all 

 the sandy and glauconitic deposits intervening between the Gault- 

 clay and the Chalk-marl of any locality in England as belonging to 

 the Upper Greensand. Afterwards, when the Chloritic Marl was 

 separated from the series in the Isle of Weight, its existence in other 

 parts of England was not properly established — or, to speak more 

 correctly, different inland horizons were assigned to it by different 

 writers. 



The type of the Upper Greensand was supposed to exist in 



