310 ANNUAL OP SCIENTIFIC DISCOVERY. 



I 



firmly-rooted sigillariee to have continued erect for many years in the Car- 

 boniferous period, when the sea happened to gain on any tract of sub- 

 merged land. Submergence under salt water may have been caused either 

 by a local diminution in the discharge of a river in one of its many 

 mouths, or more probably by subsidence, as in the case of the erect col- 

 umns of the Temple of Serapis, near Naples, to which serpulse and other 

 marine bodies are still found adhering. Sir Charles next entered into 

 some speculations respecting the probable volume of solid matter con- 

 tained in the carboniferous formation of Nova Scotia. The data, he said, 

 for such an estimate, are as yet imperfect, but some advantage would be 

 gained could we but make some slight approximation to the truth. The 

 strata at the South Joggins are nearly three miles thick, and they are 

 known to be also of enormous thickness in the district of the Albion 

 mines, near Pictou, more than one hundred miles to the eastward. There 

 appears, therefore, little danger of erring on the side of excess, if we take 

 half that amount, or 7,500 feet, as the average thickness of the whole of 

 the coal measures. The area of the coal-field, including part of New 

 Brunswick to the west, and Prince Edward's Island and the Magdalen 

 Isles to the north, as well as the Cape Breton beds, together with the con- 

 necting strata which must have been denuded, or must still be concealed, 

 beneath the waters of the Gulf of St. Lawrence, may comprise about 

 36,000 square miles, which, with the thickness of 7,500 feet before as- 

 sumed, will give 7,527, 168,000,000,000 cubic feet (or 51,136.4 cubic miles) 

 of solid matter as the volume of the rocks. Such an array of figures con- 

 veys no distinct idea to the mind, but is interesting when we reflect that 

 the Mississippi would take more than two million 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. Forshey, 450,000 cubic feet per 

 second throughout the year, and the total quantity of mud to be, as esti- 

 mated by Mr. Riddell, 3,702,758,400 cubic feet in the year. We may, how- 

 ever, if we desire to reduce to a minimum the possible time required for 

 such an operation, (assuming it to-be one of fluviatile denudation and dep- 

 osition,) 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 

 respect 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, indicating an ancient soil now under- 

 ground ; 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 up- 

 wards below the level of the sea. As the strata pierced through contained 

 fresh-water remains of recent species of plants and animals, they imply a 



