SUCCESSION AMONG ROCKS. 281 



less unreasonable to expect an absolute correspondence 

 between those of Paris and the Isle of Wight, or 

 among the whole of these that have been discovered, 

 than that the secondary strata should adhere to a 

 constant order all over the world. There is a general 

 analogy throughout nature in the successions, as 

 there is in the characters of rocks ; but the particular 

 instances are modified by laws of a local nature, ope- 

 rating in a limited spot, and subject to uncertain 

 modifications in many of these. I might add, that 

 they might even differ in the same deposit or cavity, 

 on a principle formerly laid down, namely, that the 

 present submarine deposits of the English channel, 

 the probable types of past strata, if not the germs of 

 future ones, are not everywhere similar and corre- 

 sponding in order. 



It remains to say a few words on that which has 

 been sometimes used as an expedient for preserving 

 the integrity of this theory. It applies equally to the ?# 

 primary and secondary strata; and the examination-*/ 

 of it has therefore been reserved to the last place. ^ 

 The term subordinate, already noticed, forms the 

 whole of this contrivance ; but it is necessary here to 

 explain its application. If a series be produced in 

 proof of irregularity, consisting of gneiss, argil- 

 laceous schist, and quartz rock, and if it is a part of 

 the theory that gneiss only should be found in it, the 

 other rocks are called subordinate. If, in any place, 

 two or more beds of some particular sandstone should 

 alternate with limestone, the integrity, place, and 

 order of the sandstone is preserved for the purpose of 

 the hypothesis, by calling the latter subordinate. In 

 all these cases indeed, it is usual to drop altogether 

 the name and history of the intruding beds. Fidelity 



