360 Dr Daubeny on the Volcanoes of Auvergne. 
settle our belief as to the long-agitated question of the igneous 
or aqueous origin of trap-rocks in general. 
These being the objects of my journey, you will not expect 
from me any attempt to lay down in a map the boundaries of 
the strata, or to determine with precision their geological rela- 
tions. 
Such an employment, indeed, seems to belong at all times 
rather to the native of the province, or at least of the countrv, 
who has frequent opportunities of repeating his observations at 
successive periods, than to the foreigner, whoj with all the dis- 
advantages of defective information, and want of familiarity with 
the language and manners of the people, devotes a few weeks to 
the examination of an extensive district. In the present instance, 
however, a Geological Survey of Auvergne (had it been prac- 
ticable) was foreign to the object of my visit, which had chiefly 
in view the ascertaining whether there was such an analogy be- 
tween the rocks of Auvergne and those in Scotland and the 
north of Ireland, which we usually find compared to them, as 
would oblige us to extend to the latter the same inferences 
which seem adopted by almost universal consent with regard to 
the former country. 
I shall, therefore, begin by assuming, that the rocks which in 
Auvergne are found to occupy so large a surface, are the re- 
lics of volcanoes, and that there is among them such a distinc- 
tion of character as leads us necessarily to infer that they are of 
very different dates, and may be distinguished by the names of 
Ancient and Modern. 
If there be any of your readers that object to this division, as 
founded upon theoretical considerations, it may be replied, that 
there is that marked difference in character between the rocks 
which we refer to the one or other of these classes, as perfectly 
warrants our placing them under different heads ; and there- 
fore, that such as do not agree in their interpretation of the facts, 
may still follow us in the order in which we arrange them. 
Now, the volcanic rocks which we have chosen to distinguish 
as above, are known by this important circumstance : The ancient 
like rocks of Neptunian origin in general, are cut through 
by the valleys which now exist ; whilst the modern follow exact- 
ly the inequalities of the ground, so as to afford the most con- 
