THE CRYSTALLINK ROCKS NEAR ST. JOHN, N. B. 19 



Overlying all these arc deposits wliieli hav^e not yet 

 been consolidated into rock. These are : 



6. Glacial debris, or " drift," covered in places by gravels. 



7. Marine clays, or " Ledaclay," formed whea the land 



was lower than at present. 



8. Marine sands, " Saxicava sand," formed in a shallow 



sea. 



9. River alluvium and salt marsh, (the land at or near its 



present level, and) the deposit still forming. 



It is only with the first two members of the series of 

 stratified rocks that I propose to deal at present. The 

 later rocks, showing clearly their original character of 

 sand and mud, and yielding unquestionable evidence of 

 their age in the form of fossils, are of interest chiefly to 

 the palreontologist. But the pre-Cambrian rocks contain 

 practically no direct evidences of life, and are, besides, so 

 much changed that it is often difficult to tell what they 

 originally were. 



The Metamorphism op Kocks. 



One is apt to think of a rock as something fixed and 

 unchangeable — and so indeed it is, if we measure by our 

 own short span of life. But in the time-scale of the 

 geologist, rocks, like living forms, are seen to change 

 with changing conditions. 



To go back to the beginning, the first crust of the 

 earth must have solidified from a molten mass, or 

 *' magma," as it is called, much like the lavas of modern 

 volcanoes. Whether this crust formed over a liquid 

 interior, or one mostly solid, is a matter of conjecture, 

 though the weight of evidence tends to show that now, 

 at all events, the earth is solid throughout, and molten 

 areas, if they exist, are only of local extent. The rock 

 of the original crust would be composed of minerals 



