ever with the underlying Old Red Sandstone and Carboniferous formations. Let any one consult a geological map of the district or county with which he is most familiar, and he will find how little information it conveys respecting the superficial accumulations; and then let him reflect on the connection between these accumulations and the aspect and fertility of the country, and he will perceive at a glance the importance of such delineations as we are now contending for. As well, indeed, might the artist attempt to present the aspect and outlines of the human form by its skeleton, as the geologist the physical geography or geology of a country without its superficial formations.

But altogether independent of their practical or industrial value, such mappings are absolutely necessary in a purely scientific point of view. The geology of a country by no means closes with even the latest of the so-called "Stratified systems." The old boulder-clays and glacial drifts, the carse-clays, the lake-silts, and peat-mosses, have all their tales to tell of change and time-of changes as important in the history of the globe as those that accompanied the older rock-systems, and of time so vast that we vainly endeavour to reckon it by any standard of years and centuries. What changes have taken place in the physical aspects of these islands of ours since the glacier filled their mountainglens and the iceberg floated on their estuaries; what mutations in their vital aspects since the whale and the seal frequented their sea-lochs-the mammoth, the reindeer, and Irish elk their plains and valleys-and the beaver, bear, and wild boar their rivers and forests; and what revolutions in human history since the pre-Celtic savage paddled his log-canoe across their lakes, made his feast of shells by their sea-shores, or sheltered himself in their caverns! And

yet of all these changes we have no other record save that preserved in these old carse-clays, lake-silts, peat-mosses, and cave-earths-those Superficial Accumulations, in fine, which, though often described in words, are seldom or ever attempted to be delineated on our geological maps, or traced in our geological sections.

IN THE FIELD!

WE have searched for plants, dredged for shell-fish, and, as the sneer goes, "hunted for butterflies;" but of all natural-history pursuits, that of geology is, to our mind, the most exhilarating and thought-inspiring. Botany and zoology have no doubt their charms and attractions, require much research and discrimination, and bring us in contact with some of the subtlest problems that can engage the human intellect; but they deal with the recent, and with a phase of the world which at best is but temporary and external. Geology, on the other hand, deals with the internal as well as with the external, with the past as well as with the present; lifts the veil from the extinct, and marshals in chronological order the long line of events, physical and vital, which constitutes the history of our globe from the current hour back to the remotest ages. All physical change, all vital relationship, all continuity of law and of order, come within the range of its cognisance, requiring the minutest observation and the most exact and sequential reasoning. Even as a mere field exercise, geology has higher and more permanent allurements. Botany and zoology, however attractive their objects, are restricted in a great measure to certain seasons of the year, whereas

the objects of geology are ever patent-in the precipice, ravine, and sea-cliff; in the quarry, mine, and road-cutting -wherever there is a rock-surface exposed, or a section presented to investigation. Be it the excitement of searching for fossils, the bracing exertion of climbing over ledge and scaur, the deeper thought inspired by a survey of wild ravines and hoary mountain-heights, or the freer breathing and wider scope of the breezy upland, there is something ennobling in a geological field-day that we seek for in vain in any other pursuit. Even the ordinary objects of the public highway become invested with interest to the geologist unknown to other travellers, presenting fresh subjects for examination at every turn, and suggesting new problems for solution. Let us glance at some of these objects, and the new importance they assume when viewed from the stand-point of the working geologist.

Breakfasted, and off at eight on a fine summer morning with staff in hand, bag a-shoulder, and hammer and chisels in waist-belt, the young geologist is presented with a thousand objects beneath and around him that would pass unobserved by the ordinary excursionist. Out of, but scarcely beyond, the suburbs of the town, there is the stone-breaker busy at his heap of blocks and boulders gathered from the adjacent fields, or carted from the neighbouring sea-shore. A mere heap of road-metal! True, but what a wonderful assemblage of rocks-quartzites, granites, porphyries, greenstones, felstones, and jaspers-enough to teach the whole science of lithology, or fill a cabinet with specimens of the primitive rock-systems! And then, what wonderful incidents in world-history these despised blocks and boulders suggest! Wear and waste from far-off hills; grinding and rounding by ages of attrition; transport by ice-sheet or iceberg in distant epochs, when this island of

ours lay mantled in snow and ice, or, sunk beneath the ocean, received the drift of berg and floe as they melted away in the upper sunshine. Let no one who values the teachings of his science pass indifferently by the heap of road-metal, whether consisting of miscellaneous boulders from the fields, shingle from the sea-shore, greenstone from the hills, chert from the limestone scaur, or flint from the chalk-pit. Each has its own lesson fraught with information, or its problem to suggest. Nor let him despise the knowledge of the homely stone-breaker, or refuse to listen to his quaint questions and often quainter theories. There may be curious ideas simmering in that bonneted grey head; strange intelligence peering through the wire-gauze that shades those twinkling eyes of his. We have been led to a knowledge of some of the finest intersecting dykes of basalt, and some of the strangest varieties of chalk-flints we ever witnessed, by a friendly chat with an honest labourer as he took his simple meal by the dusty wayside. And what has been the luck of one may readily be the luck of all, if they will only exercise a little frankness and affability to secure it.

Onwards our young friend goes, and the road which would seem dull and monotonous to the uninitiated, presents to him objects of interest and instruction even in its very fences. These, for the most part, are built of the nearest and readiest material-here of sandstone, there of green

here of blocks trenched from the neighbouring fields, and there of limestone too impure to be reduced to quicklime. These road-fences form in general the best and readiest indices to the geology of a district, and he who notes them attentively is not only premonished of the rock-formations that lie around him, but sees also the manner in which they are affected by exposure to the weather. Often has the examination of a roadside wall led to the knowledge