83 



the river Salado, which flows through the flat alluvial plains to the south of tne city of 

 Buenos Ayres. They were placed at the disposal of Sir Woodbine Parish, K.H., by 

 Don Hilario Sosa, the owner of the property on which they were found, and were pre- 

 sented by Sir Woodbine to the Eoyal College of Surgeons. They form the subject of 

 the Memoir by William Clift, Esq., F.R.S., published in the ' Transactions of the Geo- 

 logical Society,' Second Series, vol. iii. p. 437. 



In 1834 Mr. Charles Darwin discovered remains of the Megatherium on the shores 

 of the bay called ' Bahia Blanca,' in latitude 39° S., about 250 miles south of the Rio 

 Plata : they were impacted in a mass of quartz shingle, forming an irregularly stratified 

 mass divided by curved layers of indurated clay, and constituting the lower bed of the 

 cliff called ' Punta Alta,' about 18 miles from Monte Hermoso, North Patagonia. The 

 pebbles are cemented together by calcareous matter, probably resulting from the decom- 

 position of numerous imbedded shells. These remains are preserved in the Museum of 

 the Royal College of Surgeons, and are described in the volume of the ' Fossil Mam- 

 malia of the Voyage of the Beagle,' &c, 4to. 1840, p. 100. pi. 30. 



In 1837 a second nearly entire skeleton of the Megatherium was discovered by Signor 

 Muniz in the river Luxan, near the locality of the first discovered specimen : this was 

 deposited in the Museum at Monte Video. In 1838 Dr. Decalzi discovered on the 

 estate of Don Manuel Rosas, called ' Las Averias,' north of the Rio Salado, various 

 bones of the Megatherium. Other specimens, subsequently discovered at Luxan, were 

 transmitted by Mr. Falconet, in 1845, to London, and were purchased by the Trustees 

 of the British Museum : they are noticed at p. 11, and form, with the specimens pre- 

 viously transmitted to London, the subjects of the descriptions and figures in the 

 present work. 



From the foregoing summary it appears that the Megatherium ranged from the State 

 of New York to Northern Patagonia, being restricted by the nature of its food, its 

 habits and organization, to the latitudes most favourable to the growth of trees. 



The geological and palseontological evidences concur in showing that the formations 

 in which its remains have been found are of the newer pliocene period, coeval apparently 

 with those which contain the remains of the Mammoth and Megaceros in Europe. Of 

 twenty-three kinds of shells determined by Mr. Sowerby in the collection brought by 

 Mr. Darwin from the Megatherium-shingle at Punta Alta, twelve are certainly iden- 

 tical with existing species, and four are probably so, the doubt partly arising from the 

 imperfect condition of the specimens. These species, moreover, still inhabit the bay on 

 the shores of which they are found fossil. 



The conclusion to which Mr. Darwin arrived as to the comparatively recent period 

 of the shingle strata at Punta Alta, is nearly the same as that to which he was led by 

 observations on the beds in which the megatherian remains were imbedded in the 

 Pampas and river-courses of the province of Buenos Ayres. "We may suppose," he 

 writes, "that whilst the ancient rivers of the Plata occasionally carried down the 

 carcasses of animals existing in that country, and deposited them in the mud of the 



