MINERAL PRODUCTIONS OF UITENHAGE. 121 
— when fresh broken, inclining to grey with 
some lustre — contains in 100 parts : — 
Carbon, or charcoal S7~ 
Volatile, or earthy matter 37f 
Ashes, or earthy matter 25 
It is also impregnated with magnetic iron. 
In the same vicinity, about ten miles inland 
from the ocean, several small fossil shell-fish 
have been found ; together with large beds of 
sea-shells, which are now frequently collected 
and burnt for lime.* 
to Avermon's " Practical Mineralogy," p. 40, in which the following 
passage occurs, relative to this ore of copper, as found in North Ame- 
rica ; 1 There are very few instances in which the ore in these veins 
will pay for the labour and expense of excavation and transportation.' 
" I record these few observations, merely for my own satisfaction, to 
show what my opinions really are, and the ground I have — or fancy 
I have — for entertaining them. I have not, hitherto, and I do not 
now conceal that my opinions of the paying qualities of these mines 
are not favourable : but I shall be most happy to find that I have been 
mistaken. I believe a very erroneous notion is widely prevalent, to 
the effect that men, who take an interest in science, are so tenacious of 
their opinions, as to wish to support them through right and wrong. 
I totally disclaim any such feeling for myself, and, I believe, may 
safely do so for the majority of my brother amateurs in science. I 
have often had to change, and to modify, opinions on points of science, 
and would always rather be convinced that I am wrong, than remain 
in error." — E. Eoubridge, M. D., Algoa Bay. 
*** The above, as here inserted, was presented to the Author, for 
use, by the Hon. W. Fleming, of Port Elizabeth, South Africa, to 
whom his best thanks are due. 
* Many of the shells, both as fossils and in their present perfect 
state, belong to that species of the miocene formation in the tertiary 
deposits, which geologists style the Cardita Ajar. It is worthy of 
note, that this shell, in its fossil state, is largely found throughout 
England and France at the present day, although it exclusively be- 
longs to Africa, in its animated and inhabited form. 
