GEOLOGY. S37 



as to the time taken for the accumulation of the whole mass, laid down, as 

 it must have been, under circumstances utterly unlike those now existing. 

 The mud of the old delta of the Nerbudda, in Guzerat, now forming a bank 

 of seventy feet in thickness, the surface of which, above Broach, twenty 

 miles from the Gulf of Cambay, is thirty feet above the highest flood, divides 

 into flakes of from one-fourth to one-eighth of an inch; and yet we are not 

 certain that each of these may not be the deposit of a single freshet of a few- 

 days' or hours' duration, rather than the accumulation of an entire season. 



" The layers of sharp desert sand, seen in many places on the banks of the 

 Nile below Cairo to alternate with the mud, may probably have been depos- 

 ited on the dry surface of the soil, during some of the movements referred 

 to. A descent of the land, after this had occurred, would permit the mud, 

 now lying many feet in thickness over them, to be deposited without dis- 

 turbing them ; running water would have removed the sand, and mingled it 

 with the mud. The extreme abruptness of the transition from delta silt to 

 desert sand, from extreme fertility to absolute barrenness, astonishes the 

 stranger; near the pyramids you may actually, and without figure, have 

 one foot on arable land, and the other ankle deep in desert sand." 



With regard to the remains found in morasses and peat-mosses, Ronnie, 

 in his essay " On the Natural History and Origin of Peat-moss," has shown 

 that the rapidity of growth of these deposits is so great as to have produced 

 an immense mass of accumulation during the time which has elapsed since 

 the Roman invasion ; Roman roads and causeways being frequently trace- 

 able for miles among the mosses of Annandale, Lanark, and Perthshire. 

 The well-known case of the Guadaloupe skeletons, which were found im- 

 bedded in hard limestone, among the detritus of sand, shells, and corals, at 

 the base of steep cliffs on the northeast coast of the island, and which arc 

 now generally considered to be those of a tribe of natives, which was slaugh- 

 tered by a hostile tribe and buried on the sea-shore not more than one 

 hundred and fifty years ago, would seem to belong to the former rather than 

 to the present division, in which Dr. Anderson has placed it. 



Under the third head are included the remarkable bone-caves which have 

 been found, often at a considerable elevation above the sea, in various parts 

 of the British islands, in the neighborhood of Palermo, and in other places, 

 in which human bones, together with flint implements of human manufac- 

 ture, have been found in company with the remains of carnivorous animals 

 of great size, some belonging to genera which have been long extinct. The 

 argument which has been grounded on these discoveries depends upon the 

 conclusion that these human and animal remains must necessarily be of 

 contemporary origin. According to Dr. Anderson, this conclusion is not 

 only no necessary sequence from, but is actually inconsistent with, the 

 observed facts. If the human beings and carnivorous animals whose bones 

 are now found mingled in one common tomb had ever been alive together, 

 we should have expected to find the remains of the former gnawed and 

 broken; a condition in which, apparently, they do not occur. Dr. Anderson 

 concludes that these caverns, already containing the fossil remains of ani- 

 mals, were from time to time used as habitations by men. Their elevation 

 above the sea he accounts for by the upward movement which, as is now 

 well known, the coast-lines of many countries are even at this moment 

 undergoing; and he further suggests that such upheaval, if sudden and 

 rapid, as in the neighborhood of volcanic centres at least it mitiht well be 

 supposed to be, would cause fissures in the rocks, into which a mixture of 



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