J. SHIPMAN : ANCIENT BEACH AT CASTLE DONINGTON. 



35 



The lowest bed of the Keuper in other locahties is occasionally a 

 brecciatecl conglomerate, and it seemed not unlikely therefore that 

 this breccia formed the base of the Keuper here. In order to test 

 the question I had a trial hole made to the depth of three or four 

 feet. No Carboniferous rock was met with, however ; but, instead, 

 a chocolate-red argillaceous sandstone, containing lenticular seams of 

 greenish-yellow fine-grained clayey sand, that somewhat resembled 

 Lower Mottled Sandstone. Mr. Horace Erowm had a similar trial 

 hole made during our visit in 1884, in order, if possible, to reach the 

 Carboniferous rocks through the " feather edge ' of the Keuper, as 

 they were nowhere else visible ; but with no better success. A few 

 weeks afterwards the sinking of the large well for the new gasholder 

 showed that we had got down to within a few inches of the Carboni- 

 ferous rocks in each case. 



The gasholder-well was excavated to a depth of twelve feet below 

 the level of the road, and was about seventeen yards in diameter 

 It passed through the lowest beds of the Keuper, and penetrated the 

 Carboniferous strata to a depth varying from two to tv^'elve feet. It 

 was then seen that the Keuper not only rested on the highly inclined 

 and truncated edges of the Carboniferous strata, but that the Keuper 

 rested on a succession of terraces, which had been cut back into the 

 Carboniferous shales and grits. Indications of three distinct terraces 

 could be made out, the middle one extending very nearly the full 

 width of the excavation. The Carboniferous rocks consisted of 

 thin alternations of red, yellowish-brown, purple, white, and pale 

 mottled greenish shales, containing in the upper -part of the series 

 exposed (i) beds of hard brown and bluish-grey sandstone, with 

 traces of plant remains ; (2) concretionary hematite ironstone, and 

 (3) very hard compact purple grit, one of the beds of the latter being 

 nine inches thick. The strike of the Carboniferous strata trended 

 from S. 40^ E. to N. 40' W., or roughly south-east and north-west, and 

 therefore the true direction of the dip was S. 50^ W., or nearly 

 south-west. 



A curious fact in connection with the dip of the Carboniferous 

 strata was that the inclination shown in the opposite sides of the 

 excavation did not tally, as might be expected, one side (the east) 

 showing a maximum dip of 34°, the other (west) a dip of 45 \ Nor 

 did the beds altogether match on the two sides of the excavation as 

 they ought to have done. This suggested some disturbing agent. 

 There was no distinct evidence of a fault, however. On the west 

 side there was some appearance of a hitch or slip having taken 

 place, but it could not be traced passing across to any other point, 

 though the exposure of the Carboniferous on the south side was so 



Feb. 1887. 



