Vol. 67.] PERMIAN TO THE TRIAS IN NOTTINGHAMSHIRE. 83 



farther north underlies the Upper Magnesian Limestone. There 

 has never been any question raised as to the age of this Marl, 

 which was traced by Aveline from Yorkshire to Nottingham ; 

 and detailed mapping confirms the continuity of the bed, at least 

 as far as from Nottingham to Warsop. 



If this passage of Permian into Banter is accepted, there is no 

 escape from the conclusion that the Upper Magnesian Lime- 

 stone of Yorkshire is of the same age as some part of 

 the Bunter of Nottinghamshire. Although the passage is 

 an apparently perfect one, it might be thought that there is a 

 concealed break somewhere — the break representing the higher 

 Permian beds of Yorkshire. The evidence for a true passage is, 

 however, greatly strengthened by the sections exposed along the 

 Great Northern and Midland Railways, between Nottingham and 

 Kimberley. 



(6) Sections on the Great Northern and Midland 

 Railways, between Nottingham and Kimberley. 



The Great Northern sections were fully described by Edward 

 Wilson in 1876, so that a brief account will suffice here. 



The section shows Coal Measures unconformably overlain by a 

 breccia, which is succeeded by the flaggy, calcareous sandstones 

 with shales, known as ' Marl Slates.' These pass upwards into 

 the ' Magnesian Limestone, here (as usual in South Nottingham- 

 shire) a flaggy rock, composed of rhombs of dolomite set in a cement 

 of carbonate of lime. The limestone is succeeded by red Permian 

 Marls, which appear to pass upwards into a mass of sandstones 

 with bands of marl ; and these indefinite strata, which Wilson 

 considered to be a link between the Permian Marl and the Bunter, 

 and for which he therefore used the symbol ef, merge imperceptibly 

 into Lower Mottled Sandstone. Wilson, however, did not actually 

 call these indefinite strata ' passage-beds,' as they required further 

 study. A breccia, as much as 5 feet thick, though locally absent, 

 was taken as the base of the true Lower Mottled ; but Wilson shows 

 that precisely similar breccias occur well within undoubted Banter, 

 as, for example, at Kimberley Knowl, close by. 



It may be pointed oat here that the presence of breccia in the 

 Lower Mottled Sandstone in the Great Northern cutting, and its 

 absence in the Great Central cuttings previously described, is 

 readily accounted for by the proximity of Kimberley to the old 

 shore-line of the Permian sea. The thick basal breccia of the 

 Permian and the sandy ' Marl Slates ' above it, similarly contrast 

 with the thin breccia followed by grey marls, found below the 

 Magnesian Limestone near the Great Central cuttings. 



Many of the details described by Wilson can still be seen, and 

 the Midland Railway cutting, which is approximately parallel to 

 the Great Northern section, confirms the evidence of the latter. 



The presence of the indefinite band of strata between the Permian 

 Marl and the Bunter at Kimberley, 6 miles from the Great Central 

 cutting, strongly confirms the idea that there is a true passage 

 between the two formations. G 2 



