Chap. XVI.] 
PALAEOZOIC SUCCESSION. 
405 
Infinitely more intense, therefore, must have been that much more 
deeply seated agency which, giving rise to such internal writhings of the 
earth, inverted thousands of feet of strata over vast areas, and, in some 
tracts bending them like reams of paper, placed them abruptly in others 
over deposits formed at immeasurably subsequent periods. Striking, how- 
ever, as are the above-mentioned features of inversion, still grander ex- 
amples will be adverted to in the last Chapter. 
After all, such phenomena are only local exceptions, as respects the 
surface of the globe, on which, fortunately, the original impress of order 
is visible over very large regions. Eeverting, then, to such order, I annex 
the accompanying Table of the natural divisions of the Devonian and 
Carboniferous rocks of the Continent as compared with their equivalents 
in the British Isles, the whole surmounted by the Permian rocks de- 
scribed in the Thirteenth Chapter. In this Table, the student sees at 
one glance the whole of the Upper Palaeozoic succession, — the Silurian 
System comprising the larger portion of the Lower Palaeozoic rocks. The 
Table is substituted for one on a more limited scale given in the first 
edition of this work, relating to the tracts described in this Chapter only, 
and which was prepared chiefly to show both the triple subdivision of 
the Devonian rocks, and also that not one of those groups, as based upon 
the distribution of former life, is in unison with the lithological groups 
and systems of the late M. Dumont*. That eminent geologist, who had 
so admirably reduced to order the complicated and often inverted strata 
of his native country around Liege, undervaluing the weight of fossil 
evidence, proposed a classification based solely upon the mineral character 
of each succeeding mass. Such a division, being found to be inconsistent 
with the great principle of modern geology (strata identified by their 
organic remains), is no longer adverted to, and the Table now laid before 
the reader, though still susceptible of improvement, will, I trust, be found 
applicable to wide areas of the earth's surface. 
* See ' Siluria,' 1st ed. p. 381. 
