^{page 359 note 1} It may be found advisable to class the Upper Palæozoic Rocks, like the Lower, into one system with three Primary divisions. In that case the term Devonian would be applied, in a better sense, as the lowest of the Primary Divisious in that system.

^{page 359 note 2} The term Silurian may possibly occur to some as suitable, but to my mind it seems entirely out of the question, as comparatively only a few of the groups,—none indeed of the more important of the lower groups,—occur anywhere within the limited area formerly occupied by the Silures.