NARRATIVE. 75 



the flames to seize upon each fresh tree, winding round it hke ser- 

 pents, crackling and rushing furiously through its branches to the 

 top, until every fragment of dry bark, lichen, &c., was consumed. 

 The fire seems too dainty to take the more solid parts, and so, for 

 instance, the bunch of upright cones at the top of the balsams, re- 

 mains distinguishable in the forest as a blackened tuft. Our beautiful 

 bear-berry lawn looked now more like a peat-bog. When we left, 

 the fire was in full progress, and was proba^bly stayed only by a 

 swamp beyond. 



Nature, however, generally provides that no land that can be of 

 much value to man shall be subject to this fate, for the heavily-tim- 

 bered (and thus fertile) land of these latitudes is mostly too wet to 

 burn, except the solitary birches, which if you set a torch to them, 

 go off like rockets, but do not set fire to the other trees. 



We passed terraces several times to-day, and in one place in par- 

 ticular, on a grand scale at the bottom of a bay, forming a series of 

 vast unbroken arcs of about a mile chord, ascending one above the 

 other to the height of several hundred feet, and, from the scantiness 

 of the vegetation, evidently compjosed of sand. 



Camped on a beach of coarse, dark sand, under a high abrupt prom- 

 ontory, enclosing it with precipitous walls. Among the rocks in our 

 neighborhood were discovered veins of copper, suggesting to the Pro- 

 fessor some remarks, which he illustrated on his black canvas, 

 pinned against the side of his tent : 



" Veins are formed sometimes by the cracking of igneous rocks as they 

 cool; sometimes also by the subsidence of strata; cracks being formed, are 

 filled from the melted mass below, pressed upon by sinking strata and 

 thus forced upwards, or thrown up by other causes. The injected mass, 

 even though originally the same as that into which it penetrates, may yet pro- 

 duce a vein of a different character, from the difference of cooling. Where 

 the injected mass is very great it alters the surrounding rock, more or less 

 in proportion to its vicinity to the melted substance. In these metamorphic 

 rocks, as they are called, such as we have seen in great abundance 

 throughout our passage along the lake shore, there is accordingly the 

 greatest variety of character, and one species of rock passes into a,nother by 

 so many intermediate forms that it is often difficult to say what name should 

 be given to it, the rock, originally sandstone, perhaps, with various admix- 



