622 
APPENDIX. 
[C. 
latter case they have some resemblance to the trunks or 
roots of trees. — A mass, which seems to have been of this 
description, is stated to have come from a height of about 
two hundred and fifty feet above the sea, at Bald-head, on 
the South Coast of Australia. These specimens, however, 
do not really exhibit any traces of organic structure; and 
so nearly resemble the irregular stalactitical concretions 
produced by the passage of calcareous or ferruginous so- 
lutions through sand that they are probably of the same 
origin ; indeed the central cavity of the stalactite still re- 
mains open in some of the specimens of this kind from 
Sweer’s Island in the Gulf of Carpentaria. The specimens 
from Madeira, presented to the Geological Society by Mr. 
Bowdich, and described in his notes on that island! , ap- 
pear upon examination to be of the same character. — But 
there is no reason to suppose that the trunks of trees, as 
well as other foreign substances, may not be thus incrusted, 
since various foreign bodies, even of artificial production, 
have been so found. Professor Buckland has mentioned a 
specimen of concreted limestone from St. Helena, which 
contains the recent shell of a bird’s eggj; and M. Peron 
states that, in the concretional limestone rock of the South 
Coast of New Holland, the trunks of trees occur, with the 
vegetable istructure so distinct as to leave no doubt as to 
their nature §. 
* Tubular concretions oi ferruginous matter, irregularly ramify- 
ing through sand, like the roots of trees, are described by Captain 
Lyon as occurring in Africa. — Lyon’s Travels, Appendix, p. 65. 
t Excursions in Madeira, 1825, p. 139, 140; and Bull, des 
Sciences Naturelles, vol. iv. p. .322. 
t Geol. Trans, vol. v. p. 479. 
§ Peron, ii. p. 75. 
