120 Scientific Reviews. 
position of the masses, or the relation of one rock to another. 
And it thus belongs to the geognost to study the . differences which 
occur in the mechanical texture and chemical nature of the same 
formations, in different geographical situations,—to study the laws 
by which these rocks have been regulated in the order of their su- 
perposition, and the accidents that may subsequently have happen- 
ed to them,—to trace the relation that exists between the organic 
remains in the representatives of similar catastrophes,—and to study 
the share which the sudden or the continuous action of the agents 
employed by nature, could have had in producing the present con- 
figuration of our planet: and to these soon may be added, the in- 
vestigation of the succession of deposits, and of organic creations, 
in their relation to existing races. 
The numerous theories whose exposition adorn the beginnings of 
elementary works, are not entirely useless. They contain many 
facts of importance to be known. They show the method of rea- 
soning which ensued when geognosy first became a positive science ; 
and we think that they can but impress the reader with the absur- 
dity of attempting to unravel, by bold speculation, those sublime 
facts, which in no one case has nature allowed us to explain with- 
out patient investigation and industrious research. Of the two 
volumes under review, Dr. Ure’s work, “‘ a System,” and, besides, 
an attempt to “ reconcile modern science and sacred history,” con- 
tains most records of this kind ; and thus stand prominent, resear- 
ches on the historical character of Moses, on the illogical procedure 
of geological theorists, and on the new era of practical geology, of 
which era his notion is not, however, very complete or satisfactory. 
Of the book on the creation we must speak favourably, as being 
adapted to‘modern discoveries ; and though we do not at all admire 
discussions of that nature, yet it has always happened hitherto, that 
when the views of science did not exactly coincide with the Mosaic 
records, it has ever originated in the imperfection of our knowledge. 
And the late discoveries. of the propagation of heat, Dr Young’s 
beautiful statement respecting a disregarded property of light, and 
our increased knowledge of the properties of the atmosphere, may 
all be read with interest, as testimonies of this important truth. 
Whether we consider rocks solely according to the analogy of 
their composition, or according to the laws of their super-position, 
we shall not find that in the primitive or inferior order, the analy- 
sis of the formations given by either of the two authors, will lead 
to a very clear conception of the truth. A method wholly oryctog- 
nostical, multiplies the names of rocks more than the wants of geog- 
nosy require, when positions alone are considered ; and thus the 
study of a small granitic tract, might in some situations furnish us 
with many mineralogical varieties ; but in point of position, we are 
acquainted with, 1. Granite alternating with no other rocks, though 
affording support to many, rich in quartz, and less abundant in mica. 
2. Granite alternating with gneiss, sometimes super-imposed on the 
former, and accompanied with subordinate beds. 3. Stanniferous 
