Ermyn Street or Stane Street of the maps, which English tongues here have named Pebble Lane, skirts Ashtead Park by the south-east, at first a wide green lane, afterwards a narrow path sometimes half-choked by trees, sometimes, in wet weather, impassable with mud, but always driving straight as the Roman roadmaker drove his pick towards the cap of Mickleham Downs. The narrow lane to which the road has shrunk is less than the Roman made it, but Mickleham Downs can look very little different to-day from the downs which the legionary knew. He, too, like the modern traveller tramping by the yews and box trees, saw the sunlight on the dark, shining leaves, and watched the wind ruffle the whitebeams on the shoulder of the hill. [Illustration: _Mickleham Church._] Below the downs lies Mickleham, halfway between Leatherhead and Dorking, and famous in all the guide-books for the "swallows" of the Mole. The "swallows" are described as deep, blue pools, into which the Mole disappears underground, and, except from the most carefully written accounts, you would imagine that the whole river dives completely into the earth and jumps up again at Leatherhead. But if you ask at Mickleham to be directed to the "Swallows," the chances are that you will have to explain that you do not mean birds. The fact is that it is only in seasons of great drought that they would be noticed. In summers when there is very little rain the Mole is said to run dry between Burford Bridge and Thorncroft Bridge near Leatherhead, but I have never happened to see it do so, and had the greatest difficulty in discovering the Swallows, which, when I saw them, were brimming with very muddy water; the stream was as full as possible. The best comment on the legend of the diving Mole is Thomas Fuller's in the _Worthies_:-- "I listen not to the country people telling it was experimented by a goose, which was put in and came out again with _life_ (though without feathers); but hearken seriously to those who judiciously impute the _subsidency_ of the earth in the interstice aforesaid to some underground hollowness made by that water in the passage thereof." The Swallows are really fissures in the chalk bed of the stream, which runs as it were over the top of a long chalk sponge. In rainless summers there is only enough water to fill the bottom of the sponge, and the top channel runs dry. Brayley has some amusing calculations as to the amount of water which the sponge drinks:-- "From calculations made on different days, after measuring the height and velocity of the current received into these pools, it was ascertained, when both were in activity, that the swallows of the outer pool engulphed 72 imperial gallons per second, 4,320 per minute, and 259,200 per hour; and those of the inner pool, 23 imperial gallons per second, 1,380 per minute, and 82,800 per hour."