OEIGIN OF CRYSTALLINE EOCKS. 23 



whether, with the help of modern physical and chemical science, and our present knowledge 

 of geological facts, it is jiossible to devise such a one. After many years of reflection and 

 study, the present writer ventures to propose a new hypothesis, believing that while avoid- 

 ing all the difficulties of those hitherto piit forward, it will furnish an intelligible 

 solution of a great number of hitherto unsolved problems in the i^hysiology of the globe. 



II. — The Development of a New Hypothesis. 



§ 47. The history of the beginning and the growth of the new hypothesis here proposed 

 to explain the origin of crystalline rocks is necessarily to a great extent personal, since 

 it covers the work of many years of the author's life. The lines of investigation which have 

 led to this hypothesis may be described as first, that of the order and succession of the 

 crystalline stratified rocks of the earth's crust ; secondly, their mineralogy and lithology ; 

 thirdly, their history, considered in the light of physics and chemistry, involving an inquiry 

 into all the chemical relations of existing rocks, waters and gases, including the transfor- 

 mations and decay of rocks, and the artificial production of mineral species ; and fourth and 

 lastly, the probable condition of our planet before the creation of the present order. The 

 adequate discussion of all these themes, which would include a complete system of 

 mineral physiology, is impossible within the limits of the present essay, but a brief 

 outline of some of the chief points necessary to the understanding of the hypothesis will 

 here be attempted. 



§ 48. As regards the order and succession of the crystalline rocks, the author's studies 

 of them, begun in New England forty years since, and continued in Canada from 1847 

 onwards, were for many years perplexed with the difficulties of the Huttonian tradition, 

 (then and for many years generally accepted in America) that the mineral character of these 

 rocks was in no obvious way related to their age and geological sequence, but that the 

 strata of paleozoic and even of cenozoic times might take on the forms of the so-called 

 azoic rocks. It was questioned by the partisans of the Huttonian school whether to 

 the south and east of the azoic rocks of the Laurentides and the Adirondacks, in North 

 America, there were any crystalline strata which were not of paleozoic or of mesozoic age, 

 although many of these are undistinguishable from the rocks of the Laurentides. 



As I have elsewhere said, the metamorphic and the metasomatic, not less than the 

 exoplutonic hypothesis, of the origin of the crystalline rocks, by failing to recognize the 

 existence and the necessity of an orderly lithological development in time, have powerfully 

 contributed to discourage intelligent geognostical study, and have directed attention 

 rather to details of lithology and of mineralogy, often of secondary importance.*^ That a 

 great law presided over the development of the crystalline rocks, was from the first my 

 conviction, but until the confusion which a belief in the miracles of metamorphism, 

 metasomatism, and vulcanism had introduced into geology was dispelled, the discovery of 

 such a law was impossible. 



§ 49. Convinced of the essential truth of the principles laid down by Werner, and 

 embodied in his distinctions of Primitive, Ti-ansition and Secondary rocks, I sought, during 



<" Amer. Jour. Science, 1880, xix, 298. 



Sec. Ill, 1884. 4. 



