444 MIS,. E. M. DEELEY ON THE PLEISTOCENE 



would be necessary to carefully niap the whole area. A rough 

 survey showed that the Early Pennine Boulder-clay probably extends 

 some distance along the south side of the valley between Rearsby 

 and Frisby. No sections are to be seen, but its presence was 

 inferred from the results of some shallow borings. 



On the north side of the Wreak, though the deposit is better 

 exposed, its relationship to the later sands and clays is not so easily 

 traced, owing partly to the presence of numerous lateral valleys, and 

 partly to subsequent disturbances. 



At Thrussington, in Woldgale Lane, a clay-pit shows a deep 

 section of Boulder-clay capped by what appears to be Quartzose Sand 

 about 9 feet thick. The sand, which is here reddish, is probably 

 much thicker than the section showed. In this pit is exposed at 

 least 30 feet of fine, tough, silty Boulder-clay, with included masses, 

 streaks, or irregular beds of unstratified moraine. These morainic 

 masses have been forcibly intruded or even dropped into the sur- 

 rounding clay. Though the main mass of the deposit is a tough 

 silty clay, it is thickly studded with very small fragments of rock 

 and occasional boulders. The boulders are well striated, especially 

 the Lias limestone. Keuper marl, green mar], quartz pebbles, and 

 a few Pennine rocks also occur. The quartz and quartzites are 

 most plentiful in the intruded morainic portions. Oolitic and Cre- 

 taceous rocks are quite absent. 



The clay extends at least as far as Hoby, and maintains a con- 

 siderable thickness throughout the whole distance. Its junction 

 with the underlying rock is nowhere exposed, but at Thrussington 

 it is said to become more stony and sandy towards the bottom. 



Many sections which will be referred founder the Middle Pennine 

 Boulder-clay stage perhaps really belong to the present one, but 

 owing to the lithological similarity of the deposits of the two stages, 

 and the absence of the Quartzose Sand from the sections, their 

 absolute ages cannot be determined with any degree of certainty. 

 My main reason for deferring their consideration to a later stage is 

 due to the much more positive evidence we have of intense glacial 

 conditions towards the close of the Older Pleistocene Epoch. 



2. Quartzose Sand, 



Passing beneath Middle or Newer Pleistocene deposits, capping 

 the hills at considerable elevations, or interbedded with Older 

 Pleistocene Boulder- clays, there are deposits of fine, light yellowish 

 or reddish false-bedded sand or gravel. 



That the submergence which these deposits indicate was very 

 considerable in this part of Britain is proved by the occurrence of 

 Quartzose Sand at Blackwall, near Kirk Ireton ; on the Long HiUs 

 north-north-west of Nottingham ; and on the hill-top east-north-east 

 of Gelston, 6 miles north of Grantham. 



At Blackwall, one mile south-west of Kirk Ireton, in Derbyshire, 

 there is a very fine section of this sand. It is about 25 feet thick, and 

 consists of coarse sand or grit derived apparently from the breaking 

 up of the Yoredale Sandstone which forms the ridge upon which it 



