in Nottinghamsliire and Lincolnshire. 257 



Rampton Beds. At Lincoln the Green Beds are well developed, but 

 the lithology of the normal Waterstones is so similar to that of the 

 Keuper Marls that they were thought to be absent. This led to the 

 coarse red sandstone (some beds pebblj-), below the Green Beds, being 

 assigned to the Keuper Sandstones— as I think, quite erroneously. 

 The fact that water was struck at 1,561 feet, and that no cores were 

 then obtained until a depth of 1,577 feet was reached, also bears out 

 my interpretation, for it frequently happens that there is a strong 

 rush of Bunter water, which washes out the loose sandy top of the 

 Pebble Beds, when the Green Beds are passed through in borings. 



It has been stated ^ that in Lincolnshire the Triassic beds form one 

 series " displaying modifications in texture, colour, and composition, 

 which have no more than a local value ; it is in some cases even 

 difficult to decide where a boundary can be drawn between the Marls 

 • and the Sandstones, for beds of sandstone occur in the Marls and beds 

 of marl in the Sandstones from top to bottom of the series". A.t 

 Lincoln, however, the Green Beds represent a distinct horizon whose 

 value has been shown to be of more than local importance, and one 

 which is independent of whether the Waterstones are of the sandy or 

 marly type. 



In the Haxey (Southcar or Idlestop) boring for coal it is difficult 

 to fix the base of the Keuper, but it probably occurs (on the evidence 

 of the quantity of blue marl) somewhere near the level given in the 

 table. 



Interpreting the Scunthorpe section in the light afforded by those 

 at Hampton and Lincoln, I should place the base of the Waterstones 

 at 1,027ft. Sin. from the surface, throwing all the pebbly sandstone 

 (the Waterstones in Notts are almost invariably free from pebbles, 

 except in their basal conglomerate) below it (525 ft. 4 in.), and at 

 present assigned to the Waterstones and Keuper Sandstone, into the 

 Bunter, to which a thickness of only 196 ft. 11 in. is allotted. This 

 classification receives confirmation from the succession determined 

 by a boring near Crosby, situated a very short distance from the 

 Scunthorpe site. 



Conclusions. It will thus be seen that although the Green Beds, 

 in the present state of our knowledge, do not form a very trustworthy 

 guide to the underground position of the Bunter surface in the district 

 north of Gainsborough, they are to he depended upo7i in the area which 

 extends from that place as far south as the Yale of Belvoir, and as 

 far east as Lincoln. They should therefore be of peculiar interest to 

 all who may have occasion to probe the Pebble Beds beneath their 

 overlying cover. 



The average dip of the Bunter Pebble Beds determined from their 

 contoured surface (see Map) is roughly 94 feet per mile, but near the 

 outcrop the dip is slightly higher,^ viz. 105 feet per mile. 



^ Professor P. F. Kendall, Final Bex^ort of the Royal Commission on Coal 

 Supplies, pt. ix, p. 33. 



* Geology of the Coimtry around OUerton (Mem. Geol. Surv.), 1911, p. 25. 



DECIDE V. — VOL. IX. — NO. VI. 17 



