Mr HOPKINS, ON RESEARCHES IN PHYSICAL GEOLOGY. 5^ 



if the elevatory force act at C with a considerably greater intensity 

 than at M, it will communicate to the mass CC'NM, together with its 

 general upward motion, a rotatory one, of which the axis will be hori- 

 zontal and perpendicular to the transverse boundaries. This motion will 

 tend to depress the extremity 31, particularly if CM be of sufficient length. 

 No such cause will exist in the adjoining mass AA'XM to loMer its 

 extremity N; and moreover it may be remarked, that this mass once 

 elevated is more likely to be supported by the debris produced by a con- 

 vulsive movement such as we are supposing, and therefore its extremity 

 A'^ will be less likely to subside than the adjoining extremity of the con- 

 tiguous mass. From these causes it would seem highly probable that 

 these two portions of the general mass should assume the relative posi- 

 tions above represented. A partial elevation and escarpment may thus 

 be produced in accordance with the general fact stated in the Intro- 

 duction, (iv. fi. p. 7.) 



We may also observe, that the fault thus formed at iV must 

 very generally possess the character mentioned in the Introduction, 



(I. 7- P 2.) 



54. In the diagram, page 46, DEFG may represent a section pa- 

 rallel to the general axis of elevation of the portion of the mass 

 which we have supposed, in the preceding article, to be subsequently 

 elevated in a greater degree than the portions contiguous to it on either 

 side, as represented in the diagram of the following page. If we conceive 

 the portion also of which the section is F'D'E'G' (p. 46.) to be raised 

 in the same manner, it is obvious that a transverse valleij will thus be 

 formed between these two partial elevations, such as described in the 

 Introduction, (v. p. 8.) 



55. A section of one of our partial elevations above mentioned, by 

 a vertical plane parallel to the axis of the general elevation and the 

 longitudinal fissures, will now present an appearance (taking the phe- 

 nomena as far as we have yet investigated them) similar to that of 

 the annexed diagram, in which DEFG represents the portion of tlie 

 mass defined by the same letters in the diagram of page 46. The broken 



