139 
considerable amount of attention has been directed to the 
dip of the beds, and the distances vertically of the upcast 
from the downcast, there appears a deficiency of published 
information connected with the horizontal distances, or with 
the horizontal extent of the fissures into which trap rock, &c. 
has been forced. Yet this information must lead to the 
most important results, if we consider the causes of a 
phenomenon to be as well worthy of philosophical inquiry 
as is the evident phenomenon itself. 
Sir It. Murchison mentions in his work, " Siluria," that 
there is a fault near Wolverhampton, which is 140 yards 
wide ; and in the same work he mentions several which 
are of great width. 
To test this matter thoroughly, it requires that the dip 
of the beds on each side should be measured, as well as 
the horizontal distance between the fractured ends. The 
horizontal distance of the beds would then require to be 
divided by the cosine of the angle of dip, to obtain the true 
horizontal distance of the beds, and hence the horizontal 
extent of the fault, after which the amount of elevation 
might be easily calculated by the following formulae : — 
C A X X Y 
C X = and A X = C A — AX. 
A B 
Where C A = present radius of Earth. 
A B = present length of strata -|- the horizontal width of fault. 
X Y = length of strata — fault. 
C X = former radius of earth. 
A X = elevation of strata since deposition. 
Probable Causes. — We will now consider the probable 
causes which have produced the elevations shown by the 
evidence of the faults, intrusions, &c, to have actually 
occurred. 
To cause vast portions of the earth's surface to be raised 
from the ' direction of the centre, it is necessary that the 
masses of matter lying deep down in the centre of the 
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