GEOLOGY lying about, appears to be at least 300 yards long and 100 yards across. The nearest point from which this mass can have come is at Waltham-on-the- Wolds, about 5 miles to the north-east. Other large transported masses of rock occur near Belton, Ashby Magna, and south of Lutterworth. VALLEY DRIFT A later deposit of clay and stones is found in many of the valleys. This, although not a true Boulder-clay, appears to have been formed in late glacial times, as the material is often thrust into the underlying beds, showing that some ice existed at the time. It is of no great thickness, and is only found along valleys that have been cut through the older Boulder-clay. These beds evidently mark a very late period merging into the time when the terraces of the existing rivers were laid down ; and consequently the separation of them from the river beds is very obscure. They in fact form a connecting link between beds of glacial age and the alluvial deposits of the present rivers. They are best seen at Barrow-on-Soar, but occur also in the neighbourhood of Market Bosworth and other places. RIVER-GRAVELS AND ALLUVIUM All the main rivers of the district are flanked by well-marked river terraces, composed of well-stratified gravel and loam. They form terraces at from fifteen to twenty feet above the present alluvium of the rivers, from which they usually rise in a sharp bank. These gravels make considerable spreads at the junction of the Wreak and Soar at Syston, and along the Trent Valley north of Kegworth and other places. They extend in many places up the lateral valleys, and in the upper part join on to the alluvium of the present streams. A great number of mammalian remains have from time to time been found in these gravels. 1 These beds have been deposited at a time when the rivers flowed at a higher level, and when there was a greater volume of water than at the present time. With regard to the modern alluvium which flanks all the larger streams there is little to be said beyond that it forms fertile meadows and pastures, while the gravel terraces above are mostly arable land. The general inference to be drawn from the Drifts of this district is that the glaciation which produced these deposits of Boulder-clay and gravels emanated from two distinct sources. The earliest had its origin somewhere to the north-west, and derived its material solely from rocks older than the Trias. This glaciation, however, does not appear to have been so extensive as that which succeeded, and which, bearing Cretaceous and Jurassic rocks mingled with material from the earlier Boulder-clay, must have come from an easterly direction. The large quantity of gravel and sand associated with this Boulder- clay seems to point to the fact that the termination of the glacier cannot at times have been far from this district, although it varied somewhat at different periods. In fact there is every probability that the Midland counties occupied what was the fringe of the great glaciation that occurred at this period ; and that the frequent advance and retreat of the ice-sheet over this district produced along its edge the complicated series of torrential and swampy deposits which now form the Glacial beds of this part of England. 1 Montagu Browne, The Vertebrate Animals of Leicestershire and Rutland. 1 17 3
