210 Prof. Siuinnerton — Dreikanter Periods in S. Notts. 



Throughout 40 yards of the section tlie loose pebbles were so 

 numerous as to form lenticular accumulations of coarse gravel, which 

 at one point swelled out to a thickness of 2i feet. The only portions 

 of the Bunter conglomerate which can be compared with these are 

 the pockets of pebbles that occur here and there at the bottom of the 

 channels, which give the rock its current-bedded appearance. One 

 of these pockets cropped out at the wind-swept surface and produced 

 a slight tump which was completely covered by the gravel. Even 

 in these pebbly portions of the Bunter sand fills up the spaces between 

 the pebbles, all of which are rounded. In the gravels, on the other 

 hand, sandj'' matrix was absent and wind- worn and facetted stones were 

 common (PI. XVI, Pig. 3, /, ff, h, i). Moreover, the line of separation 

 between the gravel and the underlying Bunter was perfectly defined. 

 There can be no doubt, therefore, that these ' dreikanter '-bearing 

 gravels were laid down under very different conditions from those 

 which accompanied the formation of Bunter deposits, and that they 

 must have been formed after the latter had been subjected to the 

 action of aerial denudation for some time. 



ISTor is there any question of the gravel having been transported 

 into this position by currents of watex-, for the angles between the 

 facets show no signs of having been blunted by rolling ; on the other 

 hand, they are buried under a very fine Keuper clay which could 

 only have been laid down in tranquil water. 



Confirmation of the occurrence of this episode in the history of the 

 Trias of South Notts is forthcoming from the sand-pits at Dale Abbey, 

 which lies just beyond the western county boundary. There the 

 Bunter-like sandstone, which lies directly upon the Coal-measures, 

 yields typical 'dreikanter'. For reasons which Avill be given in 

 a later paper there is good ground for suspecting that these beds 

 really belong to the same level as the ' dreikanter ' gravels of 

 Arnot Hill. 



These Triassic wind-worn or wind-accumulated deposits are too 

 discontinuous and limited in extent to account for even a fraction of 

 the facetted and allied pebbles found in the drift. Whilst, therefore, 

 a few may come from this source, the main mass of them must have 

 been shaped by post-Glacial agencies. 



To-day, when the wind is blowing over the Bunter outcrop the 

 dust and sand raised from the landscape gives the effect of advancing 

 cavalry. Drifts of sand 3 or 4 feet deep accumulate on the lee 

 side of the hedges, and it is part of the ordinary duty of the farm 

 labourer to redistribute the sand thus displaced by the wind. Such 

 facts as these tempt one to believe that even up to the time when 

 these lands were first enclosed for cultivation, ' dreikanter ' were 

 being carved. The fact that they seem to be confined to the top 

 18 inches of soil might be taken to point the same way. Nevertheless, 

 certain phenomena associated with other gravels than those already 

 mentioned seem to limit the main period of effective wind action to 

 late Pleistocene times. 



In the vale of the Trent near Nottingham there are two sets of 

 gravels: the younger, which carpets the floor of the vale, everywhere 

 underlies the alluvium, and occasionally rises up into low flat-topped 



