33 



SOME TRACES OF AN ANCIENT (KEUPER) BEACH 

 AT CASTLE DONINGTON. 



JAMES SHIPRIAN, F.G.S., 



A nthor of papers on ' The Drift and Alhnnal Deposits of the Trent I 'alley -near Nottingliavt *; 

 ' Triassic Rocks of Cheshire mid NottiiigJiain '; ' Story of the Hemlock Stone '; 



(Abstract of a paper read l)efore the Nottingham Naturalists' Society, November 1886.) 



Excavations for the extension of the gasworks and the laying down 

 of a new gasholder at Castle Donington, about twelve miles south- 

 west of Nottingham, in the autumn of 1884, exposed to view for a 

 short time a rather interesting section. The gasworks are situated in 

 a lane that runs at the foot of the Trent escarpment, on the north 

 side of the village, and stand on a narrow strip of Carboniferous 

 rocks that are shown on the Geological Survey map of the district as 

 rising to the surface here from beneath the Lower Keuper, which 

 forms the escarpment. The excavation happened to be made on the 

 line of junction of the two formations, and so exposed to the light 

 of day a fragment of the beach of the old Keuper lake. The section 

 not only revealed the Lower Keuper resting across the truncated 

 edges of the Carboniferous strata (Fig. i), but also showed that for a 

 time at any rate, during the early part of the Keuper period, this spot 

 formed probably the northern boundary of the great inland salt lake 

 in which we know the greater part, if not the whole, of the Keuper 

 sediments were laid down. Many other sections have been described 

 at one time or another in various parts of the Midlands, all more or 

 less interesting, wherein the Keuper strata have been seen resting on 

 older rocks ; and in some of them — notably, those where the Keuper 

 is seen resting on the flanks of the pre-Cambrian rocks of Charn- 

 wood Forest — there is vivid evidence of how the old land that 

 surrounded this ancient lake, or that still reared its head above the 

 waters in the form of islands, as a large part of what is now Charn- 

 wood Forest must have done at this period, slowly sank until it was 

 ultimately overwhelmed with the red sediments that now constitute 

 what vv^e call the Keuper. But no exposure that I am aware of has 

 ever exhibited terraces so well-marked or showing such distinct 

 evidence of the shape of the ancient shore line that, for a time, as I 

 have said, formed the northern boundary of this part, at least, of the 

 Keuper lake as was afforded by this section. Unfortunately, how- 

 ever, the lower and most important part of the section at Castle 

 Donington — ^the part showing the actual junction — was circular, 

 being, in fact, the well of the gasholder, and therefore did not itself 

 show quite the true shape of the junction as it would have appeared 

 had the cutting been made in a straight line. But by the aid of 



Feb. 1887. D 



