Notes inserted on imperfect maps, or deduced afterwards from memoranda, are less authentic; and the process is frequently neglected.
PORTABLE-BAROMETERS, with detached thermometers, are desirable; and the best instruments are ultimately the cheapest.

But, unfortunately, barometers of every construction are very easily damaged or deranged.

The accurate determination of heights, however, though very interesting to physical geography, is comparatively of little importance to the geologist.
If the collector be a surveyor, he will know best to what purpose a Pocket Sextant, or small Theodolite, is applicable: the measurement of distances, of heights, and of the inclination of strata, etc.
...
CONTENTS OF APPENDIX C.
GENERAL SKETCH OF THE COAST.
GEOLOGICAL REMARKS.
1.

List of Rocks.
2.

Rocks identical with those of Europe.
3.