98 ME. E. L. SHEELOCK ON THE EELATIONSHIP OP THE [Feb. I9II, 



A good general account of the Yorkshire Permian was given 

 by Wilson, 1 who classified the beds as follows : — 



Upper Marls. 50 feet. A maximum. 



Upper Limestone == Brotherton Beds. 30-120 feet. 



Middle Marls. 50-30 feet or less. 



t ~„,„„ -\/r„~„^; t; t-™~ / Small-grained Dolomite, about 200 feet. 



.Lower Magnesian .Limestone. < T s- . , / ' inn . , * 



° [ Lower Limestone, about 120 feet. 



Quicksands, Marl Slates, and basal breccia, local and variable. 



The Small-grained Dolomite would seem to be the representative 

 of the limestone which forms the knolls of Mansfield Woodhouse. 

 The Lower Limestone is stated to be either thickly or thinly bedded, 

 oolitic or crystalline, with thin marly partings and occasionally 

 ripple-marks. Kirkby 2 gives a list of 31 species of fossils obtained 

 from it in South Yorkshire : of these it has eleven species in 

 common with the Compact Limestone of Durham (lowest division) ; 

 but 29 species occur also in the Middle (Shell) Limestone of 

 Durham. The Small-grained Dolomite is practically unfossili- 

 ferous. The Middle Marls are very variable in thickness. 

 Sedgwick 3 states that they are absent north of the Wharfe ; and 

 south of that river also they are sometimes absent (as, for example 

 Tadcaster). 



The Upper Limestone (or Brotherton Beds) comprises thinly- 

 bedded, white or grey, red or yellow strata, with little or no 

 magnesia. They exhibit marly partings, ripple-marks, and sun- 

 cracks. The fossils are of very few species. 



The Trias of Yorkshire is divided into two broad divisions 4 : 

 an upper, consisting almost exclusively of marls with gypsum ; 

 and a lower, more variable division, in which sandstone greatly 

 predominates. These divisions correspond broadly with the 

 Keuper and the Bunter. 



The Bunter is not capable of subdivision, even in the south of 

 Yorkshire ; and north of Bipon it cannot be separated at all from 

 the rest of the Trias. Deep borings have increased rather than 

 diminished the confusion, for Keuper characteristics may occur in 

 rocks which, from their position, ought to be Bunter. Prof. Kendall 

 remarks that the most that it is prudent to assert is, that Keuper 

 characteristics are more frequent at the top of the sandstone series,, 

 while those elsewhere diagnostic of Bunter prevail more near the 

 base. 



1 E. Wilson, 1881, p. 189. 



2 J. W. Kirkby, 1861, p. 310. 



3 A. Sedgwick, 1829, p. 103. 



4 P. F. Kendall, ' Geology ' in the ' Victoria County History of Yorkshire 

 1908, p. 5 (reprint). 



