350 GEOLOGICAL SURVEY OF THE TERRITORIES. 



gorges, but not glaciers. The case must have been far different at the 

 Eocene time, where the great atmospheric humidity is manifested by the 

 formation of the lignite-beds. 



From these remarks, and as a short resume, I am, I think, author- 

 ized to deduce the following conclusions : That the great Lignitic group 

 must be considered as a whole and well-characterized formation, limited 

 at its base by the fucoidal sandstone, at its top by the conglomerate 

 beds ; that, independent from the Cretaceous under it and from the 

 Miocene above it, our Lignitic formations represent the American 

 Eocene. 



Part II.— THE LIGNITE 5 ITS FOEMATION. 



The greatest geologist of our time, Lyell, takes as a preamble of his 

 Principles this admirable remark of Playfair : 



Amid all tlie revolutions of the globe, the economy of nature has been uniform, and 

 her laws are the ouly things that have resisted the general movement. The rivers and 

 the rocks, the seas and the continents, have been changed in all their parts ; but the 

 laws w hich direct those changes and the rules to which they are subject have remained 

 invariably the same. 



Certainly, every geologist is disposed to admit the exact truth of the 

 above assertion ; but how few of those who are called to teach geology 

 are disposed to follow the advice implied in it and "to begin their in- 

 structions in studying the changes and phenomena on which the pres- 

 ent surface of our globe is dependent, and of which, too, it is, at least 

 for a given time, the immediate result. 



The want of precise information on actual phenomena, whose under- 

 standing is important for the pursuit of geological studies, is perhaps 

 nowhere more evident than in considering how little the formation of 

 our combustible minerals is understood. It is indeed generally believed, 

 and rightly admitted now, that we have, in the peat-deposits of our 

 time, a. formation analogous to that of the coal, and that therefore we 

 have only to study this present and active production of nature to be 

 able to understand the origin of the deposits of combustible mineral of 

 former epochs. But how to make this study ? Nature's works are of 

 such a complex immensity that, simple as they appear to the mere 

 looker-on, a whole human life is often fully employed in the abortive 

 trial of unraveling the details of one of its minutest jiroductions. Peat- 

 bogs are not a comi^ouud or a mere heai) of dead matter, brought up 

 like the mud and sand of the rivers by some appreciable force. That 

 the peat has grown, and is still growing, in basins which it tends to fill 

 up to a precise degree, is well known. But this general and vague 

 assent of a truth says nothing on the mode of growing, on the materials 

 which supply the compound, on the elements necessary to its preservation, 

 on the influences affording those subsequent transformations by wbich 

 nature secretly elaborates some apparently useless vegetable debris, 

 restores them after a time as lignite, coal, anthracite, even diamond, all 

 matters adapted to the wants of our civilization. All these questions, 

 to be clearly understood, demand in botany, in chemistry, in physics of 

 the earth, not mere notions, but an intimate acquaintance which, even 

 for one of these specialties, cannot be obtained by a whole life of study. 

 There is, however, another cause of the ignorance of the phenomena 

 which accompany the formation of the peat-bogs of our time, and of the 

 Jaws which promote it. Peat-bogs have nothing attractive, nothing 

 which speaks at first to an imaginative mind, which charms it and 

 tempts it to investigation. They are like cemeteries, mere resting-places 



