Extract

In venturing to lay before the Geological Society the following observations made in the course of a journey through Devonshire and Cornwall,* I do not presume to think that I have by any means: comprehended all that is interesting in the physical structure of these counties; many observations, not only of detail, but of higher importance, have no doubt escaped me: all I pretend to do is, to give a general outline of what I have seen, and to connect those observations with such as I have, made in the other countries of Europe which I have also visited.

Among the several formations † which the greater part of geologists recognize, (understanding by this term not only the nature of the rocks of a district, but likewise the general disposition of the strata, and their relation in point of position to the surrounding country) one of the most interesting undoubtedly is that of flint in chalk, which is subordinate to the secondary formation in the great and generally admitted division of rocks into primitive, transition, and secondary.

Whatever be the country, where the formation of flint in chalk or marl occurs, it is worthy of remark:

I. That it occupies a considerable extent.

II. That it belongs to flat countries stratiform or alluvial: and what appears to me a more striking circumstance is, that as far as I know, it is to be met with chiefly on the skirt of some great chain of mountains at some distance; as if