feet thick, now constituting the London clay. The clay with which this chalk basin has been filled up, forms the site of the British metropolis and neighbourhood; it extends on the north and west to the Chalk Hills of Wiltshire, Berkshire, Oxfordshire, Buckinghamshire, and Hertfordshire. On the east it reaches to the sea, and on the south terminates at the North Downs. At the period when the deposit was being formed, the temperature of the locality was of a much higher character, and the neighbouring shores produced a variety of tropical plants and animals. The abundance of vegetable fossils found, resembling the cardamom, date, areca, cocoa, and a berry analagous to coffee, gives rise to the supposition that the neighbouring land constituted a group of spice islands, the shores of which were, judging from the animal remains, the haunt of various species allied to the crocodile, the turtle, the shark, &c. In excavating this formation in making the railway, immense numbers of marine shells of extinct species, remains of crabs, lobsters, &c., sharks' teeth, bones of fishes, crocodiles, and turtles, and a variety of tropical vegetables were found, which latter appear as if they had been drifted by a current into the ancient gulph.

The Oxhey Lane cutting is about a mile and a half in length, and in its excavation 372,000 cubic yards of earth had to be removed. It is crossed by several bridges, the principal one of which is the Oxhey Lane bridge, which has three arches, and is remarkable for the height it stands above the line. It is just before we arrive at the bridge that the imagin

ary line which separates the counties of Middlesex and Hertfordshire crosses the railway. On leaving the excavation, the train dashes along an embankment nearly as high as the cutting was deep, and from this may be gained an extensive view of the surrounding country. The train now enters another cutting, and just after we pass the Watford Heath Bridge, which has three arches, and is of a gigantic character, the line runs on the Watford embankment, and crosses the London road, on a viaduct of five arches, the central one of which spans the coach road. We are now

on the great Watford embankment; the town is beneath it on the left, and the train is flying above the house tops of the good townsfolk, upon a mound of the most gigantic nature, which great work has sprung into existence in consequence of the Earl of Essex's

opposition to the line going through his park. The view all along the embankment is extensive and pleasing; on the left is the PARK of Mr. King, in which groups of deer may be observed. Behind the park, on the river Colne, are the SILK MILLS of Mr. Shute, and looking onwards, in the same direction, the scene is closed by woodlands belonging to the PARKS of Lord Grosvenor and Baron Vau han. Close to the line is the town, partly hid by the trees; the gasworks, workhouse, and church spire of which, are conspicuous: the river Colne, which we cross on a viaduct of five arches, winds close to the embankment.

On the right side, the Colne may be seen fringed with willows, meandering down the valley, amidst rich meadows and pastures, and the uplands in the distance crowned with woodlands. The embankment is about a mile and a half long, and in places upwards of forty feet high; the materials of which it is composed, are chalk and gravel, of which it took nearly one million cubic yards to make this enormous mound, which is the largest on the line. The viaduct by which the Colne is crossed, is 312 feet in length, from one end of the parapet to the other, and fifty feet in height from the river; it is made of brick, with stone cornicing, and has an elegant appearance from the meadows below; the whole rests for a foundation on platforms of wood, which are fixed in the loose soft clay which composes the valley. The erection cost nearly 10,000l. Owing to the want of stability in the soil of which the Colne valley is composed, many slips have taken place in the embankment, and much anxiety given to the engineers,