Vol. 67.] THE PEKMIAN AND TRIAS OF NOTTINGHAMSHIRE. 91 



shallow- water formation, as is shown by its frequent cross - 

 bedding", the presence of sand-grains, and the breccia into which 

 it passes at Nottingham. Sorby (1879, p. 85) considered it to have 

 been formed partly by precipitation and partly from organic debris ; 

 but it may be, in part at least, of detrital origin and formed from 

 the denudation of the Carboniferous Limestone of the Pennines. 



Rock-specimens were collected from points along the line of 

 section of fig. 4 for microscopic examination, namely: (1) from 

 Baxter Hill, overlooking Pleasley Vale ; (2) from the ' lied Sand- 

 stone' of Mansfield ; (3) from the sandrock in the Permian Marl 

 above the ' White Sandstone,' at Messrs. Lindley's quarry ; and 

 (4) from a gritty band in the Lower Mottled Sandstone, at the 

 quarry of the Mansfield Sand Co., Ltd., south-east of the town. 

 The first three differed from the fourth in being dolomitic, but the 

 insoluble residues were all of the same character. The bulk of 

 each residue consisted of quartz-sand, the grains differing somewhat 

 in size in the different specimens, the larger being the more 

 rounded. In addition, the residues contained more or less chert, 

 felspar, and quartzite. These latter constituents are interesting, 

 as their presence was to be expected in sediment derived from 

 the Carboniferous limestones and grits of the Pennines. A speci- 

 men taken from near the top of the Pebble Beds, in the railway- 

 cutting between Daybrook and Nottingham, may be mentioned 

 here for comparison. The insoluble residue consisted of coarse 

 quartz-sand with felspar, and a few small grains which are probably 

 chert. 



The large outlier between Mansfield and Skegby has been 

 mentioned above (p. 86), but nothing was said of the evidence which 

 it affords of a lateral passage of Permian Marl into sandrock. 

 From Skegby, as far eastwards as Eight Men's Intake, the Permian 

 Marl maintains its normal character and thickness ; but, as we 

 trace it still farther eastwards, it is seen to become much more silty, 

 and, at the large clay-pit of the Mansfield Stone & Brick Works, 

 300 yards south-east of Eight Men's Intake, it is intermediate in 

 character between Permian Marl and Bunter — in fact, it resembles 

 closely the passage-bed seen in the Great Central Railway, already 

 described. The section being an important one, details are given 

 here : — 



Thickness in feet inches. 



Soil 2 



Keel marl with green streaks 1 6 



Red marly sandstone seamed with marl; green sti-eaks... 1 6 



Red marl with green streaks 1 6 



Hard red marly sandstone I 3 



Do. do. with green streaks 1 



Eed marl 4 



Eed fine-grained sandstone 1 1 



Red marl 1 



