GEOLOGY OF PATAGONIA. 221 



height of 3000 feet at the foot of the Cordillera. 

 I have said that within the period of existing sea- 

 shells Patagonia has been upraised 300 to 400 feet : 

 I may add, that within the period when icebergs 

 transported boulders over the upper plain of Santa 

 Cruz, the elevation has been at least 1500 feet. 

 Nor has Patagonia been aftected only by upward 

 movements : the extinct tertiary shells from Port 

 St. Julian and Santa Cruz cannot have lived, ac- 

 cording to Professor E. Forbes, in a gi-eater depth 

 of water than from 40 to 250 feet ; but they are 

 now covered with sea-deposited strata ft'om 800 to 

 1000 feet in thickness : hence the bed of the sea, 

 on which these shells once lived, must have sunk 

 downwards several hundred feet to allow of the ac- 

 cumulation of the superincumbent sti'ata. What a 

 history of geological changes does the simply-con- 

 sti'ucted coast of Patagonia reveal ! 



At Port St. Julian,* in some red mud capping 

 the gravel on the 90-feet plain, I found half the 

 skeleton of the Macrauchenia Patachonica, a re- 

 markable quadruped, full as large as a camel. It 

 belongs to the same division of the Pachydermata 

 with the rhinoceros, tapir, and pala30therium ; but 

 in the structure of the bones of its long neck it 

 shows a clear relation to the camel, or rather to the 

 guanaco and llama. From recent sea-shells being 

 found on two of the higher step-formed plains, 

 which must have been modelled and upraised be- 

 fore the mud was deposited in which the Macrau- 

 chenia was intombed, it is certain that this curious 

 quadruped lived long after the sea was inhabited 

 by its present shells. I was at first much surprised 



* I have lately heard that Capt. Sulivan, R.N., has found nu- 

 merous fossil bones, embedded in regular strata, on the banks of 

 the Rio Gallegos, in lat. 51° 4'. Some of the bones are large ; 

 others are small, and appear to have belonged to an armadillo. 

 This IS a most interesting and important discovery. 

 T 2 



