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apparent sequences in the order in which the beds tad been 
laid down; that the different strata could be distinguished by 
their fossils ; that this order of succession of different groups 
was never inverted; and, further, that they might be iden- 
tified at very distant points by their peculiar organic remains. 
This classification of the sedimentary rocks became then es- 
tablished, each division being marked by its peculiar fossils. 
The founders of the Geological Society of London thus directed 
their attention to this theory of deposition, and the active 
members of the Society have almost exclusively confined then- 
attention to this view of the science from that time to this day. 
The ideal geological sections have made this order ot deposi- 
tion familiar to all who have paid any attention to geological 
works. The ascending order of the sedimentary beds is a^ 
follows: — 1st, Cambrian and Silurian; 2nd, Old lied Sand- 
stone; 3rd, Carboniferous; 4th, New Red Sandstone; oth, Lias; 
6th, Oolite; 7th, Chalk; 8th, Tertiary As far as the sedi- 
mentary beds of England are concerned, these sections might 
be accepted as representing the general order and character ot 
the beds, provided they are not made to appear to cover each 
other over the whole area. Although this order of the beds is 
not inverted, they are not of equal extent, and are merely 
found in patches here and there, and partially overlapping 
each other, where the beds are reduced in thickness and taper 
away. Hence the sections which represent the beds as 
uniformly piled on each other, and as of equal extent, from 
the Silurian and Cambrian below to the Tertiary above, are 
erroneous. With regard to the Silurian formation, it has not 
only absorbed the Cambrian, but actually also embraces (very 
improperly) the primary slates. The first mistake made by 
geologists, in establishing this classification of the fossihferous 
rocks, was in assuming that this variety of beds was univer- 
sally the same in all parts of the world. They further erred m 
attempting to assign to each system a distinct creation, and 
in naming the series of beds in other countries according o 
the English type, without demonstrable proof of their corre- 
spondence. This hasty and very incorrect generalization, 
too-ether with the assumption that the fossils were, all remains 
of extinct species, different from those now existing, av o 
caused a very great injury to the progress of geological science, 
by giving encouragement to extravagant theories. 
A mere glance at a geologically coloured globe will show 
how insignificant, for instance, is the extent of the area ot the 
carboniferous formation as compared with the entire surface ot 
the earth. The same may be said of every other division ot the 
sedimentary series, from the Cambrian below to the iertianes 
