352 Darwin and Geology 
In a letter to Henslow in 1834 Darwin says: “I have just got 
scent of some fossil bones...what they may be I do not know, but if 
gold or galloping will get them they shall be mine’.” 
Darwin also showed his sense of the importance of the discovery 
of these bones by his solicitude about their safe arrival and custody. 
From the Falkland Isles (March, 1834), he writes to Henslow: “I have 
been alarmed by your expression ‘cleaning all the bones’ as I am 
afraid the printed numbers will be lost: the reason I am so anxious 
they should not be, is, that a part were found in a gravel with recent 
shells, but others in a very different bed. Now with these latter 
there were bones of an Agouti, a genus of animals, I believe, peculiar 
to America, and it would be curious to prove that some one of the 
genus co-existed with the Megatherium: such and many other points 
depend on the numbers being carefully preserved”.” In the abstract 
of the notes read to the Geological Society in 1835, we read: “In 
the gravel of Patagonia he (Darwin) also found many bones of the 
Megatherium and of five or six other species of quadrupeds, among 
which he has detected the bones of a species of Agouti. He also met 
with several examples of the polygonal plates, etc.®.” 
Darwin’s own recollections entirely bear out the conclusion that 
he fully recognised, while in South America, the wonderful signi- 
ficance of the resemblances between the extinct and recent mammalian 
faunas. He wrote in his Autobiography: “During the voyage of 
the Beagle I had been deeply impressed by discovering in the Pampean 
formation great fossil animals covered with armour like that on the 
existing armadillos*.” 
The impression made on Darwin’s mind by the discovery of these 
fossil bones, was doubtless deepened as, in his progress southward 
from Brazil to Patagonia, he found similar species of Edentate 
animals everywhere replacing one another among the living forms, 
while, whenever fossils occurred, they also were seen to belong to the 
same remarkable group of animals’. 
1M. ZL. 1. p. 15. 
2 Extracts from Letters ete., pp. 13—14, 
3 Proc. Geol. Soc. Vol. 11. pp. 211—212. 42.1.1 p. 82. 
5 While Darwin was making these observations in South America, a similar 
generalisation to that at which he arrived was being reached, quite independently and 
almost simultaneously, with respect to the fossil and recent mammals of Australia. In 
the year 1831, Clift gave to Jameson a list of bones occurring in the caves and breccias of 
Australia, and in publishing this list the latter referred to the fact that the forms belonged 
to marsupials, similar to those of the existing Australian fauna. But he also stated that, 
as a skull had been identified (doubtless erroneously) as having belonged to a hippo- 
potamus, other mammals than marsupials must have spread over the island in late 
Tertiary times. It is not necessary to point out that this paper was quite unknown 
to Darwin while in South America, Lyell first noticed it in the third edition of his 
Principles, which was published in May, 1834 (see Edinb, New Phil. Journ. Vol. x. [1831], 
