Exactly similar characters belong to rocks similarly circumstanced in the new red series, in many other parts of England; and have always been considered good evidence of the shore-line of the sea of the new red period. These pebbly deposits are, in fact, the seabeach of that era, and are usually covered up by, and intermixed with, sands, as modern beaches are mingled with sandbanks. The lands below the calcareous conglomerate receive the title of the lower new red or Rotheliegende, and have been described by Professor Sedgwick near Whitehaven, lying immediatly above the coal. Those which rest upon the calcareous beds constitute the new red sandstone. Above these sands, probably deposited in calmer water, usually occur finer and more argillaceous sediments, locally yielding gypsum, and in other parts of England rock-salt. These are the latest of the regularly stratified seadeposits in and around the Cumbrian Lake district. Records of many long periods succeeding this epoch, have been observed in other parts of the British Isles ; but the geological history of this particular district is here interrupted, and a wide interval of unknown duration separates the date of the new red strata from the next point of geological time, discernable in the natural monuments of the Lake districts. These monuments represent the country as subject to great surface waste, by forces acting nearly at the close of the latest of the great geological periods which preceded the commencement of historic time.

DILUVIAL AND GLACIO-DILUVIAL DEPOSITS.

The geologist who is well acquainted with the distinctive peculiarities of the rocks of the Lake district may often recognize numerous fragments, and occasionally large blocks of them, in the plains of Cheshire and Staffordshire, and on the hills and sea-cliffs of Yorkshire. If, surprised by the phenomenon, he endeavours to investigate its cause, he will remark, that, from the plains

of Cheshire, an almost uninterrupted stream (so to speak) of these travelled stones can be followed on the west of the mountainous lands of Derbyshire, Yorkshire, and South Lancashire, till it terminates in the granites and slates of the country, near Ravenglass; while from the Yorkshire coast another stream, or series of streams, of such gravel can be followed to a converging channel across the high chain of the Yorkshire hills, at Stainmoor, and from thence over the vale of the Eden, and the Crags of Orton, to the granites and slates of Shap Fells, and the syenites and elvans of Carrock and High Pike.

What has given to these streams of pebbles their determinate courses, lifting them above great inequalities of level, and yet not enabling them to overpass, except in the hollow of Stainmoor, and in one other situation in the valley of the Yorkshire Calder, the great ridge of the carboniferous mountains?

To this question four answers of a speculative character have been returned, partly founded on the general advance of geological opinions, partly on the progress of inquiry touching the phenomena of erratic boulders.

1. The phenomenon has been called Diluvial, and pronounced to be due to the great oceanic floods, uplifted and thrown suddenly, and with violence, over the land, so as forcibly to bear away fragments of the rocks and quantities of detritus, for considerable distances, over hills and valleys, and leave them in a peculiar state of aggregation. The direction which these floods have followed in the British Isles has been generally from north-west to south-east. (See Buckland's Reliquiæ Diluviana, 1821.)

2. The same effects have been ascribed, not to one cataclysmal agent, but to a succession of upward movements of the bed of the sea; which, by generating oceanic action in succession, at all points of the Lake region, would necessarily cause a drift of the disintegrated masses seaward; and the movement being supposed to happen parallel to a right line from north-east to southwest, the drift would be to the south-east, which accords

with the observations. (See Philips's Treatise on Geology, 1837.)

3. Following the traces of Charpentier among the glaciers of the Alps, M. Agassiz has given us the speculation of the transport of erratic blocks far from their original sites by the action of glaciers, believed to have occupied anciently larger areas, to have risen to greater elevations, and to have extended themselves, and carried the fragments of rocks and heaps of detritus, which usually encumber their surface and move with the moving icy mass, to greater distances. As applied to the case of the travelled detritus of the Lake mountains, this speculation requires the supposition that the whole mountain region was covered with perpetual snows, so as to become a fountain of glaciers which moved in different directions, and carried from the eastern borders of Cumberland the granites and syenites of Shap and Carrock to Stainmoor, Thirsk, and Flamborough; and from the western side, the granites of Ravenglass to Lancaster, Preston, and Manchester, leaving them in heaps and ridges like the moraines of the Alps.— (Agassiz, Etudes sur les Glaciers.)

4. The experience of Arctic and Antarctic voyagers has suggested a fourth hypothesis. In high northern and southern latitudes, icebergs-which are often only the broken-off ends of glaciers-are met with bearing loads of the rocks which originally fell on the glacier. In the course of melting, by the interference of currents, or by grounding in shallow water, these ice-rafts lose their equilibrium or their flotation, and their load of surface detritus falls on the bed of the sea, making heaps similar in several respects to the moraines left on land by glaciers, but bearing more or less of the usual characters of deposits in water, some marks of stratification, some attrition of the materials, some sorting of the masses according to weight and magnitude, some admixture of the exuviæ of animals living in the sea at the time. (Murchison's Silurian System; Lyell's Geology.)

To discuss these hypotheses at length would be equivalent to writing a treatise on the whole of the later periods of Geology. The first supposition, the uplifting of the sea, is contrary to experience, and cannot be supported by evidence collected in and around the district of the Lakes, for all the phenomena which have been cited in its favour seem to be more easily accounted for by the second hypothesis-the uprising of the land. This, however, requires the additional postulate, that nearly the whole of the mountain regions of the north of England, which had been uplifted prior to the new red sandstone, had again sunk prior to the era of detrital deposits.

The third or glacial hypothesis, perhaps, requires us to admit, on the contrary, that these mountain tracts were elevated previous to that era; and for evidence of this we are referred to the appearance of smoothed and scratched rocks, such as appear in the valleys of Switzerland, and accumulations of moraines, such as everywhere mark the actual or ancient limits of glaciers.

A remarkable case of scratched rocks was noticed by the writer in the limestone district of Conishead, near Ulverston, where the rocks were cleared from beneath a covering of detritus; but cases of this description are at least not so common nor so clear in the Cumbrian as in the Snowdonian chains.

Finally, the fourth or iceberg hypothesis, implies the elevation of the Cumbrian district, its covering of ice and snow, and its streams of glacier; and, further, requires around this elevated tract, wherever the detritus spreads, sea-channels and sea-currents. This latter condition is very easily admitted, and may, in fact, be regarded as proved (by the occurrence of marine shells), for the low vale of Eden, the low vale of York, and the low plains of Lancashire and Cheshire; that is to say, for surfaces not more than 300 or 400 feet above the actual sea level. This proof may be hereafter extended, but we must not forget the discoveries of quadrupedal bones in gravel, clay, and caverns, which appear to

prove that large surfaces in Yorkshire and the eastern parts of Lancashire were contemporaneously dry land. And thus, upon the whole, it is probable that for the distribution of the erratic boulders from the Cumbrian mountains, we may keep in view two hypotheses, viz :—

1. The rising of the whole Cumbrian region out of the sea, by gradual or periodical efforts, and the consequent littoral violence and oceanic currents which might drift the boulders and gravel over the sea-bed; and,

2. The covering of the already uplifted mountains, with glaciers, and the drifting of the broken ends of these glaciers (" icebergs"), with their load of detritus across the sea, till they melted, stranded, or overturned. But which of these views contain most of true theory, will be determined by further observation, and the general progress of geological reasoning.

PHYSICAL GEOGRAPHY.

The establishment of a correct theory of the dispersion of erratic rocks from the Cumbrian mountains is the more desirable, because its postulates involve one of the grand conditions on which the explanation of the actual surface features of the Lake district must be founded. These conditions are, in fact, four; first, the nature of the various rocks; secondly, the position in which they have been placed by disturbances in the crust of the earth; thirdly, the state in which the district was left after its elevation above the sea; and finally, the effect of subsequent atmospheric agencies.

The whole surface of the earth is undergoing momentary changes by the operation of atmospheric influences. The mountains are wasted, the valleys are