[Sidenote: Proofs of time from aqueous effects,] We must pass by a copious mass of evidence furnished by aqueous causes of change operating on the earth's surface, though these add very weighty proof to the doctrine of a long period. The filling up of lakes, the formation of deltas, the cutting power of running water, the deposit of travertines, the denudation of immense tracts of country, the carrying of their detritus into the sea, the changes of shores by tides and waves, the formation of strata hundreds of miles in length, and the imbedding therein of fossil remains in numbers almost beyond belief, furnished many interesting and important facts. Of these not a few presented means of computation. It would not be difficult to assign a date for such geographical events as the production of the Caspian and Dead Seas from an examination of the sum of saline material contained in their waters and deposited in their bed, with the annual amount brought into them by their supplying rivers. Such computations were executed as respects the growth of Lower Egypt and the backward cutting of Niagara Falls, and, though they might be individually open to criticism, their mutual accordance and tendency furnished an evidence that could not be gainsaid. The continual accumulation of such evidence ought not to be without its weight on those who are still disposed to treat slightingly the power of geological facts in developing truth. [Sidenote: and from the movements of the earth's crust.] To such facts were added all those, with which volumes might be filled, proving the universality of the movements of the solid crust of the earth--strata once necessarily horizontal now inclined at all angles, strata unconformable to one another--a body of evidence most copious and most satisfactory, yet demonstrating from the immensity of the results how slowly the work had gone on.