The high-road to Dorking goes out under the Church, to hold up the Mole valley. But the traveller not bound, Ixion-like, to a wheel, should by all means leave it by a lane just beyond the town, crossing the Mole and striking into the path above mentioned as turning off the Guildford road beside the railway. This path takes him near the river for a couple of miles, by the lower edge of Norbury Park, between its heights and those of Leatherhead Downs, a valley that becomes the finest stretch of the Mole's scenery about Mickleham, judged by some the fairest spot in Surrey.
Here, too, come the renowned "Swallows" of the Mole, with which its name was rashly connected. This phenomenon is so much insisted on by old writers that one must take it to have been more frequent and on a larger scale in former days. Camden speaks of the river as disappearing for two miles near Mickleham so completely that flocks of sheep could feed over it. In our time it sinks only at points, or is reduced to a chain of pools, after a continuance of dry weather, its current being swallowed up in subterranean recesses, as happens notably in Derbyshire, and most markedly in the Karst region of Austria, taken as the typical stage for this freak performance of nature. An eminent geologist tells us how the chasm which lets the Mole through the Downs is honeycombed beneath by a mixture of broken masses of chalk, interspersed with looser drifts. "The Swallows are evidently nothing more than the gullies which lead to the fissures and channels in the chalk rock beneath. When the supply of water in the river is copious, these hollows will be filled from above faster than the water is discharged below, and the phenomenon disappears. But when the quantity sent down by the river is small, the subterranean channels drain off the water, and the bed of the river is left dry."
Above the pretty village of Mickleham comes the most glorious _bouquet_ of the Mole, where it makes a grand curve below an amphitheatre of woods, shown from the railway in a tantalising glimpse. The lofty and leafy bank to the west is one face of Norbury Park, that so well displays its noble timber on slopes both gentle and abrupt. Its most celebrated feature is the "Druids' Grove" of yews, thus described by Mr. L. Jennings:--