Mr HOPKINS, ON RESEARCHES IN PHYSICAL GEOLOGY. 81 



as to the respective claims of two theories, one of whicli sliould assign 

 tiie phenomena of elevation, in which the law of parallelism is observ- 

 able, to the partial, and the other to the general action of an elevatory 

 force, the terms general, and partial being taken in the sense in which 

 I have heretofore used them, (see p. 1.) It must not, however, be sup- 

 posed that our theory would lead us to the conclusion, that the whole 

 elevation of any elevated range must have been communicated to it at 

 once. It requires only that \\\e first movement should have been general, 

 and sufficient to produce at least the commencement of the systems 

 of fissures, by which the range may subsequently be characterized, 

 (Art. 58). Elevations, partial or general, may afterwards take place 

 without producing other fissures following any law different from that 

 of the preceding ones. 



In the present state of geological theory, this deduction will not, 

 I conceive, be deemed unimportant. It forms no part, however, of my 

 present purpose to examine the merits of the different theories of ele- 

 vation, which have been propounded by geologists ; nor have I entered 

 into these investigations in the spirit of advocacy of any peculiar and 

 preconceived notions. ]\Iy object has been simply to develope the 

 necessary or probable consequences of certain definite hypothetical causes, 

 and to compare them with those results which appear to be at present 

 best established by observation ; but, at the same time, leaving the 

 theory of elevation founded upon our hypotheses, open to that refu- 

 tation, or more complete verification, which must arise from the com- 

 parison of the results of more extended and accurate geological research 

 with those of theory, deduced not by vague and indeterminate methods, 

 from assumptions still more vague and indeterminate, but by accurate 

 methods, from hypotheses the most simple and definite, which the nature 

 of the subject will admit of. 



In our own country the elevated range extending from Derbyshire 

 to Northumberland, seems peculiarly calculated to afford us an oppor- 

 tunity of comparing tlie results of observation with those of the theory 

 we have been investigating. On tlie slightest inspection of a map 

 of this portion of the island, the direction of the central line of ele- 

 VoL. VI. Part I. L 



