366 <A. R. Horwood—Upper Trias, Leicestershire, 
5. Trcronics anp River DrveLopmeEnt. 
Any consideration of tectonic structure must be, to some extent, 
affected by the evidence of denudation preceding and following the 
formation, of which the structure is discussed. 
There is considerable local evidence of pre-Triassic denudation in 
post-Carboniferous and pre-Permian times. ‘This is shown by the 
absence of higher beds in the Ashby district. It is shown also by 
the occurrence of hematite nodules in Permian beds containing 
plants derived from the Coal-measures. There is evidence in the 
Permian that locally the deposits are non-sequential, due either to 
land-oscillation or denudation. The Lower Keuper, as has been 
intimated, is locally deposited on the eroded surface of the Bunter, 
a feature noticed also in the Newark district. The character of the 
Triassic sediments indicates that the Palseozoic rocks were greatly 
worn down to furnish the source of their material. 
The evidence of the Drift deposits shows that much of the Trias 
has been denuded by glacial agency, the extent of which cannot be 
estimated. Furthermore, the probable formation of an earlier pene- 
plain between Liassic and recent times and a later one giving rise to 
present drainage systems must account for much modification in the 
configuration of Central England. The loss of the Keuper between 
Mesozoic and Pleistocene times was probably considerable, evidence 
of which is afforded by marls low down at 880 feet at Bardon, and 
the existence of outliers of Rhetic beds at Needwood Forest, west of 
the Charnian range. ; 
The general structure of the Upper Trias may be summed up as 
‘follows: The Lower Keuper is characterized by the sloping nature 
of the scarps formed by the sandstone features. A series of stone 
beds near the top forms a small escarpment below the Orton Sand- 
stone Series, as in the east of the Mease Valley and south of the 
River T'rent. The marly beds form flat country as in the Mease 
Valley, and less so north and south of the Trent. 
The lower part of the Red Marls present gentle slopes up to the 
escarpments of the sandstones of the Orton Group in the Mease Valley, 
and between Castle Donington and Kegworth, exhibiting sinuous 
flexures. ‘he sandstones form ridges, a medified plateau on plateau 
structure along the top of the escarpment, and where they broaden 
out and are exposed at the surface they afford flat tablelands. ‘The 
marls below exhibit gentle dip slopes. 
The Upper Keuper Sandstones, Dane Hill Series, occur as high 
eround witha steeper, less marked dip slope, and as the sandstone 
beds are more massive, but local, the hills present only small plateaux. 
In Notts the Red Marl is characterized by steep slopes with 
sharply defined upper margins bordering the flat plateaux, which 
descend gradually to the south-east, representing the dip slope of 
the marls. Here, though the position of certain skerries can be 
ascertained, their extent as in Leicestershire cannot be followed, 
and in this district the Drift obseures wide tracts: The skerries 
give rise to flat plateaux, and on the gentle dip slopes form sandy 
belts. ‘This character is noticeable also in Leicestershire. In the 
Melton district, in the absence of features formed by skerries, 
