Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.3)

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 ( Macrauchenia PatachonicaJ, mentioned at p. 208, which in some respects is allied to the Camelidaa, 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 (vo\. iii-, p- 24) says, " It is possible that the horse ought to VOL.111. 2q*