Page:A Book of Dartmoor.djvu/24
But all the other considerable streams look back upon Dartmoor as their mother.
And what a mother! She sends them forth limpid and pure, full of laughter and leap, of flash and brawl. She does not discharge them laden with brown mud, as the Exe, nor turned like the waters of Egypt to blood, as the Creedy.
A prudent mother, she feeds them regularly, and with considerable deliberation. Her vast bogs act as sponges, absorbing the winter rains, and only leisurely and prudently does she administer the hoarded supply, so that the rivers never run dry in the hottest and most rainless summers.
Of bogs there are two sorts, the great parental peat deposits that cover the highland, where not too steep for them to lie, and the swamps in the bottoms formed by the oozings from the hills that have been arrested from instant discharge into the rivers by the growth of moss and water-weeds, or are checked by belts of gravel and boulder. To see the former, a visit should be made to Cranmere Pool, or to Cut Hill, or Fox Tor Mire. To get into the latter a stroll of ten minutes up a river-bank will suffice.
The existence of the great parent bogs is due either to the fact that beneath them lies the impervious granite, as a floor, somewhat concave, or to the whole rolling upland being covered, as with a quilt, with equally impervious china-clay, the fine deposit of feldspar washed from the granite in the course of ages.
In the depths of the moor the peat may be seen