in the Coal-Measures of Nova Scotia. 223 



that the great river is joined by most of its larger tributaries. 

 Taking the quantity of sediment at one-third less than that 

 assigned by Mr Everest for the Ghazipore average, the 

 volume of solid matter conveyed to the Bay of Bengal would 

 still amount to 20,000 millions of cubic feet annually. The 

 Ganges, therefore, might accomplish in 375,000 years the 

 task which it would take the Mississippi, according to the 

 data before laid down, upwards of two million years to 

 achieve. 



One inducement to call attention to such calculations is the 

 hope of interesting engineers in making accurate measurement 

 of the quantity of water and mud discharged by such rivers as 

 the Ganges, Brahmapootra, Indus, and Mississippi, and to lead 

 geologists to ascertain the number of cubic feet of solid mat- 

 ter which ancient fluviatile formations, such as the coal-mea- 

 sures, with their associated marine strata, may contain. Sir 

 Charles anticipates that the chronological results derived from 

 such sources will be in harmony with the conclusions to which 

 botanical and zoological considerations alone might lead us, 

 and that the lapse of years will be found to be so vast as to 

 have an important bearing on our reasonings in every depart- 

 ment of geological science. 



A question may be raised, how far the co-operation of the 

 sea in the deposition of the carboniferous series might ac- 

 celerate the process above considered. The lecturer con- 

 ceives that the intervention of the sea would not afford such 

 favourable conditions for the speedy accumulation of a large 

 body of sediment within a limited area, as would be obtained 

 by the hypothesis before stated, namely, that of a great river 

 entering a bay in which the waves, currents, and tides of the 

 ocean should exert only a moderate degree of denuding and 

 dispersing power. 



An eminent writer, when criticising, in 1830, Sir Charles 

 Ly ell's work on the adequacy of existing causes, was at pains 

 to assure his readers, that while he questioned the soundness 

 of the doctrine, he by no means grudged any one the appro- 

 priation of as much as he pleased of that " least valuable of 

 all things, past time." But Sir Charles believes, notwith- 

 standing the admission so often made in the abstract of the 



