48 REPORT — 1866. 



perhaps insuperaWe, and wliicli my knowledge does not enable me to gi-apple 

 with ; viz., that if the shrinkage that contorted the strata were slow, the heat 

 resultino- from it might never have attained sufficient intensity to have produced, 

 with the aid of alkaline waters, those common metamorphic masses, known as 

 gneiss, granite, syenite, &c., and others less commonly recognized as metamorphic, 

 such as some of the quartz porphyries, for the heat thus generated may have 

 escaped as fast as it was formed. But I cannot now enter on these details. 



It has often been customary to speak of the Cumbrian moimtains as a great 

 dome, forces from below having heaved up the strata towards a central point, 

 fi'om whence the main valleys radiate as great rents produced by that upheaval. 

 But the strata of Cumberland are not dome-shaped in the true geological sense. 

 If it were so, the strata ought to dip from the centre. But instead of that we find 

 Lower and Upper Silurian strata from the equivalents of the Llandeilo flags to 

 the Ludlow beds, which though contorted, yet form an ascending series aU across 

 Cumberland from Cockermouth to Ambleside, A\ith an average south-easterly dip. 

 There is, indeed, nothing cone-Hke in the manner of their arrangement, and the 

 io-neous rocks associated with the Cumbrian strata have partaken of disturbances 

 oi the same ages as those that heaved up the Silmian rocks of Wales. Afterwards 

 the wholej series was planed across by marine denudation before the deposition 

 of the Old Red Sandstone of the area ; and then, but chiefly at later periods, the 

 valleys were scooped out from a great tableland, an old plain of marine denudation, 

 especially after the removal by denudation of the Carboniferous rocks which at 

 one time probably cased and concealed the whole of the Silurian sti-ata. In this 

 manner the character of the mountains of the country was produced, the harder 

 masses being apt to form the heights, craggy, yet often rounded by glacial action. 



Now in disturbed districts, and m many not much disturbed, faults are more or 

 less numerous, and they are of all ages and of varying amounts. On the Continent 

 of Europe and in Britain, for example, from the Middle Tertiary strata downwards, 

 somewhere or other, all the formations have been dislocated, some of the faults 

 beino- of the amount of only a few inches or yards, and others of many fjhousands 

 of feet. Several I know in \\'ales of liOOO, 5000, or even 12,000 feet in amount ; and 

 as a rule it is found that the greatest faults intersect strata that have been most 

 disturbed, while also it often happens (Ijut not always) that the oldest strata have 

 undergone most disturbance, because they have been more frequently aftected by 

 disturbino- agents. On the north side of the Alps the Miocene rocks of the Rhigi 

 are inverted and faulted agamst the older formations, and the amoimt of the throw 

 must be very large, and as many jMioceue species of moUusks are still li-\-ing, far as 

 it is removed from our epoch, this fault, by comparison with older ones, may almost 

 be said to approach our own day. 



Now the question arises whether the agencies that produced contortion of strata 

 and faults, which in certain cases have resulted in the formation of gTeat mountain- 

 chains, have been sudden in their operation, or if the changes have been as pro- 

 gressive and gradual as the operation of those agents of denudation — the sea in the 

 formation of plains of marine denudation, old and new, and the outlines of coasts ; 

 together with the work of au', rain, risers, frost, snow, and ice, that, long continued, 

 have produced the famihar sculptm-ing of hill and valley. This is a very puzzling 

 question to geologists, and various opinions have been stated. One of these is that 

 we now live in a world, as it were, nearly in a finished state, antl which will sufter 

 no more catastrophes ; another that the world now remains in a temporary state 

 of repose after a succession of spasmodic throws which broke up suddenly gi-eat 

 portions of the earth's crust, and repeatedly revolutionized the world, and that such 

 efforts may recur at later periods a long way beyond our time ; or again, that the 

 state of tranquillity we now enjoy, in which change is constant, more or less slow, 

 and very sure, has been the order for all time, as far as geologists' can trace back 

 the history of the world in the rocks that form its crust. These are the leading 

 opinions on the subject, and my own inchues to the last. 



But in the present state of our knowledge it is impossible to reduce to a demon- 

 stration the truth of this opinion. Those who fancy the world to be in a finished 

 state are seemingly forgetfid of the fact that the old rocks were made by the same 

 operations as those that are now forming ; and those who advocate sudden violence 



