On the Geological Distribution of Gold. 27 



and huge masses of gravel, sand, and clay were carried 

 forth from the more elevated tracts of South America to- 

 wards the sea, where, among others, the gigantic Megatherium 

 and Mylodon (Sloths) and the Glyptodon (Armadillo), which 

 occupied the vast plains of Las Pampas, were destroyed, as 

 testified by their remains in this and similar localities. 



What has been distinguished by "diluvial detritus," 

 whether with or without gold, is the produce of this geological 

 date, consequently the first appearance of gold among 

 fluvial depositions may, with other eventful arrangements, 

 be classed among the last of the tertiaries, i.e., the Pleis- 

 tocene period* But where we find the remains of occa- 

 sionally numerous proofs of the occupants existing pre- 

 vious to the catastrophe represented by these fosiliferous 

 depositions, we have to consider that the destruction of 

 these organic beings had been caused by a prior and prepa- 

 ratory arrangement to that of the deposition of the entombing 

 detritus, viz., the preliminary work of denudation, for certainly 

 a denudation took place previous to the successive depositions ; 

 because, wherever we observe the detritus of the epoch in 

 question, we find that it rests on the naked rock, consequently, 

 life and vegetation of the previously existing period naturally 

 suffered first the effects of the devastation which worked 

 its way down to the more solid rock, or the bed prepared for 

 the materials employed in levelling the rugged surface of 

 the earth. 



Great and awful do those preparatory geological changes 

 appear, when we view the existence of a luxuriant vegetation, 

 animated by organic life in numerous forms and enjoying a 

 tranquil possession of their respective abodes, when the hour 

 of destruction arrived, and the last denudation that our 

 globe had to suffer came to hand. It appears that among 

 the agencies employed, the most powerful consisted in those 

 from meteorological soiu-ces. We admire the wonderful effect 

 of these, though with but a faint idea about their extent, as 

 far as our present notions of such agencies reach, because, 

 since the epoch we now contemplate, our globe has not ex- 

 perienced any such floods as those producing the denudation 

 and consequent distribution of the fluvial-detritus containing 

 gold — which may be considered as partial and local changes, 

 carried on in succession all over the world. The portion 

 thus exposed to the catastrophe, became deprived ; of all 



* Pleistocene, the last of the geological divisions of the Tertiary epoch — ■ 

 revealing the recentness of the great majority of fossils. 



