94 MR. E. L. SHERLOCK ON THE RELATIONSHIP OF THE [Feb. I9II, 



Fox-Strangways, 1 at Warsop Colliery Junction, on the Lancashire, 

 Derbyshire, & East Coast Kailway, to some extent fills this 

 gap. The Magnesian Limestone was seen to be arched into an 

 anticline, and covered by horizontal Permian Marl and thin flaggy 

 limestones which merged laterally into marl. These thin limestone- 

 bands appear to be ' skerries ' — that is, the equivalents of the sand- 

 stone bands which occur in the Marl in the country to the south. 

 Just as the sandstone bands increase in importance towards the 

 top of the Marl, until they replace it altogether and give rise to 

 the Bunter, so here it may be that the thin limestones mark the 

 incoming of the Upper Magnesian Limestone which overlies the 

 Marl farther north. 



Mr. Bernard Smith informs me that he has found bands of 

 almost pure dolomite interbedded with the Keuper Waterstones at 

 several places, and especially at Westhorpe, near Southwell. 

 These dolomite bands occur in exactly the same manner as the 

 sandstone bands, which are themselves dolomitic. This is a good 

 illustration of how a limestone band such as the Upper Limestone 

 may have been formed contemporaneously with the sandstone of 

 an adjacent area. 



Although where the junction of the Lower Limestone and 

 Permian Marl is seen, south of Warsop, it is an abrupt one and is 

 sometimes an unconformity, Mr. J. B. Hill 2 has noticed a passage 

 between the two in the Shirebrook district. 



At Cuckney, where the Permian Marl can again be recognized, the 

 Survey map represents it as having a wide outcrop ; and on it, 

 at Collingthwaite, is mapped an outlier of the Upper Magnesian 

 Limestone, the southernmost appearance of this member of the 

 series. The outlier is now represented by fragments of weathered 

 limestone lying on the ploughed fields at the top of a hill, and 

 Aveline himself does not seem to have seen more than this. His 

 own account is as follows 3 : — 



' On the larger of the two outliers the limestone has been quarried. This 

 quarry has been filled up, but the fragments of the stone are strewn plentifully 

 over the field. It is a fine and close-grained stone, of a yellow colour, and it 

 appears from the fragments to be stratified in thin flag-like beds. No fossils 

 were seen in these scattered fragments, though they occur plentifully in the 

 equivalent beds in the north. The existence of the smaller outlier is only 

 indicated by the loose stones lying on the field.' 



The second outlier here mentioned is situated about half-a-mile 

 to the north-west of the larger one. The road to Holbeck Wood- 

 house, immediately under the hill capped by the smaller outlier, 

 shows a good section, in sand rock, which presents precisely the 

 appearance of typical Lower Mottled Sandstone. Aveline, 4 who 

 refers it to the ' Permian Red Marl and Sandstone ' (that is, the 



1 C. Fox-Strangways, 1898, p. 160. 



2 ' Summary of Progress for 19U8 ' Mem. Geol. Surv. 1909, p. 18. 



3 W. T. Aveline, 1879, pp. 18-19. 



4 Ibid. p. 18. 



