SERPENTINE AN IMPORTANT MEMBER OF THE UNSTRATIFIED ROCKS. 67 



great pressure, and exposed to intense heat, fusion would be the consequence ; but the ten- 

 dency of the gas to escape under those circumstances must be great ; and if, by some cause, 

 passages should be opened into caverns in the earth, there would be an immediate escape of 

 gas with great violence, and which, by pressure on itself, might cause large quantities to 

 liquefy, by which the pressure would increase until some portion of the solid crust of the 

 earth would be found to yield, and give exit to the pent up fluids. 



Another view of the subject may be presented, though it is strictly hypothetical, and per- 

 haps there are but few data upon which to found even an hypothesis. It is supposed by 

 many geologists of the present day, that during the early periods of the earth's history, a 

 much greater quantity of carbonic acid existed in a free state than at the present time ; and 

 that it was owing to this abundance of the material, so essential to the growth of plants, that 

 we are to attribute the great preponderance of some vegetable forms over those of the present 

 day. Admitting the fact, by what means can we account for such a condition, other than by 

 bringing in the aid of limestone ignited by the more powerful operation of the elements in 

 those early periods, and for the existence of which we find so many indubitable proofs ? 

 However visionary these views may appear to others, to myself they are rational ; and if 

 admitted, they explain phenomena and facts of ancient dates in a way more clear and full 

 than the ordinary hypotheses of the day. Although it is maintained in one of the most popu- 

 lar geological systems, that the powers of nature are as active and energetic at the present as 

 in ancient periods, still, after a survey of the whole subject, and of the evidence on which 

 those views rest, doubts of their correctness remain in the minds of most geologists. That 

 a more quiescent state should now prevail, and that the former violence of the elements 

 should be restrained, or rather become more feeble by a more equable balance of the forces 

 which act and react on each other, is agreeable to reason, and the benevolence of the Great 

 Architect of the Universe. 



4. Serpentine. 



Throughout the whole of the northern primitive district, serpentine forms an important 

 member of the unstratified rocks. It is not to be understood, however, that it covers large 

 areas, or forms mountain masses ; but that it is of frequent occurrence, holds important rela- 

 tions, and in an economical point of view, is well worthy of consideration. 



In giving a detailed account of a formation, or a particular rock, one very interesting view 

 in which it is to be placed, is its resemblance to, or diiferencc from, the rocks of the same 

 species in other sections of the country. By this course, we are able to discover those causes 

 which seemed to have operated in the production of those differences, or to have preserved 

 their similarity ; and besides this, we are aided in building up a rational and satisfactory 

 theorj' of the formation of the earth. 



Pursuing our geological investigations in different sections of the country, one fact is 

 brought to light, viz. that rocks of the same name, and very properly considered the same 

 species, do in fact present many remarkable differences. Granite and serpentine, for instance, 



