of hills as this of Hampstead and Highgate, very much increase one's interest in a landscape.

The horizon's rocky parapet

is to us what the outlines of a venerable and ruinous building are to the archæologist. These broken sky-lines in Nature's architecture show the ruins of a pre-existing world as clearly as broken walls and gables reveal the ruins of an ancient and timehonoured pile raised by some human architect in the far past. For, as we have already seen, the valleys of Middlesex are but breaches and clefts in an original mass of deposit which once lay superimposed for 500 feet above what is now the bed of the Thames. How insignificant the age of the most venerable buildings and monuments of man's erection, compared with the terrestrial structure whose broken horizon Nature here stretches around us,

And ruin seems of ancient pile!

But what of the climate which prevailed here in Middlesex at the time of the deposition of this London Clay, when Nature was sowing here and over a large part of Europe

The dust of continents to be!

The facts are so startling as to give us a topic for further talk as we ramble in these Hornsey pastures.

No. VI.

THE OLD SEA-BED IN MIDDLESEX-(Continued).

Where æons ago with half-shut eye,
The sluggish Saurian crawled to die.

Pictures from Appledore.--Lowell.

Prodigious rivers roll their fattening seas,
On whose luxurious herbage half-concealed,
Like a fallen cedar, far diffused his train.
Cased in green scales the CROCODILE extends.

THOMSON.

HE remains of ancient turtles have been found in abundance, embedded in the London Clay, but they haven't yet found an Alderman !" For this disrespectful correlation of Aldermen and turtles an eminent contemporary naturalist is responsible. Addressing an audience of a youthful character, Professor Huxley was seeking to inveigle them pleasantly into geological regions, and tempting them to make inquiries and researches of their own into the structure of the ground beneath them. The occasion was a pardonable one for so gentle a joke. On many successive Monday afternoons during the summer of the present year, the London Institution was the centre of attraction for a host of boys and girls from middle-class schools far and near. Soon after the hour of three, Finsbury Circus began to be invaded by caravans and troops of youngsters, most of them under fifteen years of age. They had come to hear the Professor's course of lectures on Physical Geography. They swarmed up the steps to the theatre, and overflowed the vestibules long before the time for opening the doors. The Janitor of the place had to dodge the eager crowd in the way peculiar to theatres of a more histrionic * 1869.

*

character. He opened the portal stealthily, noiselessly, surreptitiously, as if accustomed to evade human torrents bursting their barriers and carrying all before them. These youngsters-there were eight hundred or nine hundred of them, both boys and girls, mostly girls were the field-naturalists of the future-ramblers round London when the environs shall inclose their four or five millions of inhabitants. We watched their faces as they sat at Professor Huxley's feet. With earnest apprehensive looks, and with pencil in hand they took in voraciously the tale, "How this England of ours, with its 70,000 feet of sedimentary water-laid strata, has been built up," and how to compute the time the building of it has taken. The fluviatile turtles of the London Clay, and the large crocodiles whose eggs the turtles devoured, became as real to them as the contemporary turtles which have now to be imported 4,000 miles from West Indian waters; as genuine as the citizens with whose appetites the turtle-community are associated. Soon these budding naturalists will spend their Saturday afternoons in geological rambles, scanning the ground beneath them for open sections, trespassing on new railway embankments, waylaying British navvies at their work, and harassing old collectors for fossil specimens.

You have seen that our excursion into the old geological environs of London this Saturday afternoon has resulted in our acquiring a fossil trophy of the London Clay. The shark's tooth we have got from the clay-field near Finsbury Park-sharp, brilliant, and perfect as it was when the broad, shovel-headed creature sank æons ago into the mud of the sea to die-has been duly labelled with place and date of collection, and committed to our stores. We continue, as we journey, to discuss its history and the circumstances of its discovery. How can we so explain them to incredulous strangers as to command their intelligent apprehension, and belief in our story? The geologist's version of the origin and history of this London Clay, and of the animal remains we find in it, implies that a climate more West Indian than English once prevailed under this Middlesex sky. Let us stay on our route and inquire, and interchange the information we have severally gained on the subject. At this spot we may well pause and converse, for we can, at the

same time, take in the beauties of a charming Middlesex landscape. The view from Mount Pleasant, Hornsey, is one of the most pastoral and pleasing we have in our London environs. A soft and lovely northern foreground slopes down to the pretty village of Hornsey, where a few red-tiled houses amid the trees maintain the older rural aspect against contiguous suburban villas. Our hill commands as well the plains of Hertfordshire, and the meadows and woods of Essex, as they stretch to the far-off horizon. These fertile scenes belong to the basin of the river Lea, and on our left is the water-shed that divides them from the basin of the Thames. From the Highgate and Muswell heights in front of us you can turn in a moment to see across the Thames the solitary summit of Shooter's Hill in Kent, and the vivid lights which play about the roof and towers of the glass palace at Sydenham. You can see, too, almost into the heart of the great City. Towers and spires and huge roofs looming on the horizon tell you of well-known ways that lie beneath the smoke. In the foreground are

The villas with which London stands begirt,
Like a swarth Indian with his belt of beads.

From these you turn again to the soft green hills and meadows of the North.

What lover of the picturesque, what poet or painter with the eye of Thomson or Constable, could enjoy more than we the bright and living landscape before us! And yet, we remark, how much larger the canvass, and how much grander the scale, on which a Murchison or Lyell would interpret the scene! How much more impressive, and even romantic, is Nature around us in the light of her remote aboriginal history and vicissitudes than in the aspect she wears to-day. On the site of the great City, and of these fair green landscapes, a deep and vast perspective seems to open before us. The fossil worlds of distant geological ages look through the thin and transparent veil. For a moment the surface about us sinks down from the sunlight, and the marine waters of the London Clay once more extend to the horizon around. The green hills submerged become once again the reefs and shoals of an ancient sea,

For ever haunted by the Eternal mind,

though never looked upon by the eye of man. In the tepid waters gigantic sharks and crocodiles again seek their prey! Such is the vista discovered by science in landscapes which to-day in our London environs look so immutable, placid, and fair.*

The climate of the London Clay period, if the flora and fauna of the time are to be trusted, was almost tropical, instead of temperate or sub-Arctic, as now. It has been shown that reptiles of warm climates, and shells and fishes of sub-tropical seas, swarmed in this latitude. The existence of crocodiles here, whose fossil skulls have been found in the Isle of Sheppey and in other parts of the London district, is considered to give a valuable clue to the question of the former temperature of sea and land under these Middlesex skies. It has led Professor Owen to observe that,

"At the present day the conditions of earth, air, water, and warmth, which are indispensable to the existence and propagation of these most gigantic of living saurians, the crocodiles, occur only in the tropical or warmer-temperate latitudes of the globe."

Mr. Prestwich, our greatest authority on London geology, adds that two species of crocodile have been met with in the clay around London. He tells us that one bears a resemblance to the Nile species; and that the other resembles in some respects both the gavial of the Ganges and the crocodile of Borneo. In his lectures he has figured the fossil skull of the first as Crocodilus toliapicus. The fossil skull of this creature appears to be more than two feet in length. It was obtained from Sheppey.

Of the mammals of the London Clay little is known, but the most common belongs to "that curious class of extinct thick-skinned animals, which have their nearest analogue in the existing tapir of South America and Sumatra, but surpassed them by one-third in size."

Other evidences of the tropical character of the temperature are

* Some of the Old Masters in landscape art show that they too perceived the infinite and unhuman side of Nature. How vast, unsympathetic, and Sphinx-like is often the scene to which the unimportant human inci

dent of the picture is allowed to give its name. For some remarks on "the mysterious silence and inexorable deafness of Nature," see Studies in Poetry (p. 244), by Prof. Shairp.