1 64 King Georges Sound. paet i. 



casts on Bald Head ; for it is certain, that many cen- 

 turies must have elapsed since the thickets were buried ; 

 at present, owing to the form and height of the narrow 

 promontory, no sand is drifted up, and the whole sur- 

 face, as I have remarked, is wearing away, We must, 

 therefore, look back to a period when the land stood 

 lower, of which the French naturalists l found evidence 

 in upraised shells of recent species, for the drifting on 

 Bald Head of the calcareous and quartzose sand, and 

 the consequent embedment of the vegetable remains. 

 There was only one appearance which at first made me 

 doubt concerning the origin of the cast, — namely, that 

 the finer roots from different stems sometimes became 

 united together into upright plates or veins ; but when 

 the manner is borne in mind in which fine roots often 

 fill up cracks in hard earth, and that these roots would 

 decay and leave hollows, as well as the stems, there is 

 no real difficulty in this case. Besides the calcareous 

 branches from the Cape of Good Hope, I have seen 

 casts, of exactly the same forms, from Madeira 2 and 



1 See M. Peron's ' Voyage,' torn. i. p. 204. 



2 Dr. J. Macaulay has fully described (' Edinb. New Phil. Joum.' 

 vol. xxix. p. 350) the casts from Madeira. He considers (differently 

 from Mr. Smith of Jordan Hill) these bodies to be corals, and the cal- 

 careous deposit to be of subaqueous origin. His arguments chiefly 

 rest (for his remarks on their structure are vague) on the great 

 quantity of the calcareous matter, and on the casts containing animal 

 matter, as shown by their evolving ammonia. Had Dr. Macaulay 

 seen the enormous masses of rolled particles of shells and corals on 

 the beach of Ascension, and especially on coral-reefs ; and had he 

 reflected on the effects of long-continued, gentle winds, in drifting 

 up the finer particles, he would hardly have advanced the argument 

 of quantity, which is seldom trustworthy in geology. If the calca- 

 reous matter has originated from disintegrated shells and corals, the 

 presence of animal matter is what might have been expected. Mr. 

 Anderson analyzed for Dr. Macaulay part of a cast, and he found it 

 composed of — 



Carbonate of lime . « . . . .73-15 



Silica 11-90 



Phosphate of lime 8-81 



Animal matter ....... 4-25 



Sulphate of lime ...... a trace 



9«Mi 



