222 Sir C. Lyell on Fossil Reptilian Remains 



solid matter as the volume of the rocks. Such an array of 

 figures conveys no distinct idea to the mind ; but is interest- 

 ing when we reflect that the Mississippi would take more 

 than two millions of years (2,033,000 years) to convey to the 

 Gulf of Mexico, an equal quantity of solid matter in the shape 

 of sediment, assuming the average discharge of water in the ( 

 great river, to be, as calculated by Mr Forshay, 450,000 cubic 

 feet per second, throughout the year, and the total quantity 

 of mud to be, as estimated by Mr Riddell, 3,702,758,400 cubic 

 feet in the year.* 



We may, however, if we desire to reduce to a minimum 

 the possible time required for such an operation (assuming 

 it be one of fluviatile denudation and deposition), select as 

 our agent a river flowing from a tropical country, such as 

 the Ganges, in the basin of which the fall of rain is much 

 heavier, and where nearly all comes down in a third part of 

 the year, so that the river is more turbid than if it flowed in 

 temperate latitudes. In reference to the Ganges, also, it 

 may be well to mention, that its delta presents in one re- 

 spect a striking parallel to the Nova Scotia coal-field, since 

 at Calcutta, at the depth of eight or ten feet from the surface, 

 buried trees and roots have been found in digging tanks, in- 

 dicating an ancient soil now underground ; and in boring on 

 the same site for an artesian well to the depth of 481 feet, 

 other signs of ancient forest- covered lands and peaty soils 

 have been observed at several depths, even as far down as 

 300 feet and upwards below the level of the sea. As the 

 strata pierced through contained fresh-water remains of re- 

 cent species of plants and animals, they imply a subsidence 

 which has been going on contemporaneously with the accu- 

 mulation of fluviatile mud. 



Captain Strachey of the Bengal Engineers has estimated 

 that the Ganges must discharge 4 J- times as much water into 

 the Bay of Bengal, as the same river carries past Ghazipore, 

 a place 500 miles above its mouth, where experiments were 

 made on the volume of water and proportion of mud by the 

 Rev. Mr Everest. It is not till after it has passed Ghazipore, 



* See Principles of Geology, 8th Ed., p. 219. 



