CAMBRIDGE ESSAYS : IIOPKINs' '^GEOLOGY." 429 
displacement h V may not exceed, in some cases, a few feet, while in 
others it may amount to several hundred feet. In the latter case, the 
faults usually extend for many miles. 
" These faults are intimately associated with large deviations of tho 
strata from horizontality. They are almost invariably parallel to tho 
neighbouring anticlinal and synclinal lines, which themselves observe 
the same laiv of imralldism. One of the most gratifying results of tho 
labours of the field-geologist consists in this evolving of law and order 
amidst the apparent irregularity and confusion usually presented to us 
in the external features of a mountainous district. 
" Tlie complete evidence of the facts which wc have now 
described in broad outline must, of course, be sought in the labours of 
geological observers. "When the geological sense, however, is once 
awakened, we can scarcely cast our eye on a sea-cliff, a mountain- 
escarpment, or even a railway-cutting, without seeing evidence of some 
such facts as those above stated." 
Tho general arrangement of the fossiliferous or stratigraphical portion 
of the earth's crust is then given, and a concise table of the general 
arrangement of the animal kingdom. 
The latter wc transci'ibe, as it may prove useful to some of our 
readers : — 
Sub-kingdom Vcrtclrata. 
Class Mammalia. 
„ Aves. 
lleptilia. 
Pisces. 
Sub-kingdom Mollusca. 
Class Cephalopoda. 
Sub-kingdom Articutata. 
Class Crustacea. 
„ Arachnida. 
„ Insecta. 
,, Ancllata. 
,, Cirripedia. 
Gasteropoda. 
Pteropoda. 
Lamcllibranchiata. 
Branchiopoda. 
Tunicata. 
Sub-kingdom Itacliata. 
Class Piadiaria. 
„ Polypi. 
,, Entozoa. 
,, Infusoria. 
Tho first of these sub-kingdoms consists of animals of tho highest 
