$64 Mr. Hopkins’s Abstract of his Memoir on Physical Geology 
unsupported by any analogies drawn from the known opera- 
tions of nature. 
VI. There is another point on which I have touched inci- 
dentally in the conclusion of my memoir—the application of 
the principles already explained to the theory of Elie de Beau- 
mont, respecting the parallelism of mountain-chains of con- 
temporaneous elevation. I have before stated, that in what- 
ever manner we may conceive an elevatory force to be pro- 
duced, there seems no reason why we should not suppose it, 
in some cases, to have acted at a much greater depth than in 
others. Now I have already explained (p. 278) the reason 
for concluding that the formation of a system of fissures, ac- 
cording to our theory, must be simultaneous; and also how 
the simultaneous formation is facilitated by the circumstance 
of time being necessary for the transmission of the relaxation 
of the mass produced by the opening of a fissure. From that 
explanation it will easily be seen, that if a number of fissures 
commence simultaneously in the lower portion * of an elevated 
mass of great thickness, and great superficial extent, it is most 
probable that those only will reach the upper surface which 
are remote from each other. These fissures will be large, 
and all the phenomena resulting from them may be expected 
to be on a proportionate scale. Anticlinal lines + will almost 
necessarily be formed along them; and thus it is as easy to 
account for two parallel mountain ranges, as for two neigh- 
bouring anticlinal lines on a scale of comparatively small mag- 
nitude; and our theory will thus assign a physical cause for 
the Jaw of parallelism in mountain chains of contemporaneous 
elevation, as contended for by M. Elie de Beaumont, if, at 
least, the application of that geologist’s theory be restricted 
within certain limits. I have no intention, however, of now 
insisting on this extensive action of the physical cause I have 
been considering ; but I would observe, that the extent of this 
action can only be determined by that of those portions of the 
earth’s surface throughout which the laws of observed phzeno- 
mena may be continuous, and in accordance with our theore- 
tical deductions. 
To persons not habituated to the investigation of the accu- 
rate relations between mechanical causes and their effects, 
much of the previous reasoning may appear too refined to be 
applicable to our subject; but it must always be recollected, 
that this reasoning is immediately applied to hypothetical pro- 
* Lhave shown that these fissures must generally commence in some 
lower portion of the elevated mass. See Memoir, p. 43. 
+ See Memoir, p. 51. 
