68 Dr Boue’s Observatiom on M. Beudanfs Opinions^ 
line rocks of the red and’coal sandstones are not so dearly a N'ep- 
tunian product as this philosopher supposes, (Voyage en Hon- 
grie^ p. 195 .), I must recall to mind that the opinion of the ig- 
neous origin of these rocks is founded upon their miner alogical 
composition and structure^ upon their imbedded minerals^ and 
upon their geognostical position^ as I have shewn at full in my 
Essai sur VEcosse^ p. 431. It would certainly seem that proofs, 
supported by observations made upon these three points by geo- 
logists of repute, might be sufficient to induce M. Beudant, as 
well as others, to adopt a different opinion, especially when we 
find that he admits, with few restrictions, the veracity of these 
observations ; and it would seem that this being, the case, the 
opinions advanced by the volcanists have a right to be considered 
as something more than “ mere conjectures, derived simply from 
the comparison of rocks, without giving themselves the trouble 
of discussing the facts, or without attending to the geognostical 
position.” (See Travels in Hungary^ vol. iii. p. 195, line 16.) 
This remark, which has probably escaped without due reflec- 
tion on the part of its author, who on other occasions manifests 
a becoming degree of caution, is the more surprising, that among 
the proofs which he enumerates, with perfect impartiality as he 
professes to believe, as tending to establish the igneous origin of 
the trap and porphyry rocks, there is not a single one deduced 
from the geological relations of these problematic masses. 
Far be it from me to reproach this candid inquirer with par- 
tiality ; yet I cannot help observing, that perhaps he has not 
himself seen enough of similar formations, or that he does not 
think he can repose entire confidence in the detailed observations 
which many geologists have related, of the anomalous position, 
and various appearances, seen in the neighbourhood of the rocks 
in question. In the enumeration of the proofs of the igneous ori- 
gin of secondary porphyry and trap rocks, he begins with shew- 
ing the perfect identity of the secondary pitchstones with those 
of the trachytic countries, and follows out this similarity through 
nearly all its details of composition, (p. 196) ; but afterwards 
(p. 199) he tells us, among the pretended Neptunian proofs 
which he adduces, that this analogy of the pitchstone rocks of 
two different epochs, is not so complete, “ when these rocks are 
compared under more general relations.” (P. 199? line 10.) 
