ADDENDA. 



Page 76. 



I HAVE said that crystals of sulphate of magnesia, called by the Spanish 

 inhabitants, madre del sal, are scattered on the borders of the Salinas in 

 Patagonia. By a mistake a wrong bottle was examined; and the crystals, 

 I now find, are the sulphate of soda ; but it appears that some sulphate of 

 magnesia is dissolved in the underlying fetid mud. 



Page 96. 



In enumerating the fossils, which I collected at Bahia Blanca, I mention 

 a tusk like that of a boar, and , some very flat grinders. These are now 

 found to belong to the lower jaw of Toxodon Platensis. For an admirable 

 description of this wonderful animal, and likewise of the great fossil 

 f Macrauchenia Patachonica J, mentioned at p. 208, which in some respects 

 is allied to the Camelidae, I must refer to the first part of the Zoology of 

 the Voyage of the Beagle by Mr. Owen. 



Page 97. 



The remains just referred to, are said to be embedded with existing 

 species of shells. This expression requires some qualification ; the details 

 are given in my geological introduction to Mr. Owen's account of the Fos^ 

 sil Mammalia, above mentioned. 



Page 150. 



With reference to what I have said, about the bones of horses having 

 been several times brought to this country from North America, with 

 those of the Mastodon, I see Mr. Rogers, in his Report to the British 

 Association (\o\. iii., P- 24) says, " It is possible that the horse ought to 



VOL. 111. 2q* 



