We have thus an accredited explanation for the extraordinary behaviour of the river Derwent and its tributaries, including practically the whole of the drainage south of the Esk, which instead of taking the obviously simple and direct course to the sea, flow in the opposite direction to the slope of the rocks and the grain of the country. After passing through the ravine at Kirkham Abbey the stream eventually mingles with the Ouse, and thus finds its way to the Humber. The splendid canon to the north of Pickering, known as Newton Dale, with its precipitous sides rising to a height of 300 or even 400 feet, must have assumed its present proportions principally during the glacial period when it formed an overflow valley from a lake held up by ice in the neighbourhood of Fen Bogs and Eller Beck. This great gorge is tenanted at the present time by Pickering Beck, an exceedingly small stream, which now carries off all the surface drainage and must therefore be only remotely related to its great precursor that carved this enormous trench out of the limestone tableland. Compared to the torrential rushes of water carrying along huge quantities of gravel and boulders that must have flowed from the lake at the upper end, Newton Dale can almost be considered a dry and abandoned valley. [Illustration: A Diagrammatic View of Newton Dale during the Lesser Ice Age. The overflow of the glacier dammed lakes at the head of the dale came down Newton Dale and poured into Lake Pickering.] At Fen Bogs, where there is a great depth of peat, Professor Kendall has discovered that if it were cleared out, "the channel through the watershed would appear as a clean cut, 75 feet deep." The results of the gouging operations of this glacier stream are further in evidence where the valley enters the Vale of Pickering, for at that point a great delta was formed. This fan-shaped accumulation of bouldery gravel is marked in the geological survey maps as covering a space of about two square miles south of Pickering, but the deposit is probably much larger, for Dr. Thornton Comber states that the gravel extends all the way to Riseborough and is found about 6 feet below the surface, everywhere digging has taken place in that direction. The delta is partly composed of rounded stones about 2 feet in diameter. These generally belong to the hard gritstone of the moors through which Newton Dale has been carved. Dr. Comber also mentioned the discovery of a whinstone from the great Cleveland Dyke, composed of basaltic rock, that traverses the hills near Egton and Sleights Moor, two miles above the intake of Newton Dale at Fen Bogs.