IS 6.] Progresnve Chunges of Matter. 215 



of a river from its outlet to its source in mountainous countries, 

 we almost every where meet with its tributary streams, the banks 

 of which are generally precipitous. We may here begin to com- 

 prehend more fully the graphic linger of nature. The waters 

 wore their wonted pathways after the formation of the river val- 

 ley. When travelers of civilized nations began to visit the val- 

 ley of the Nile, and contemplate those stupendous pyramids and 

 other massive monuments of lock, it w«s somewhat difficult to 

 conceive from whence the materials were procured; but as these 

 travelers visited the upper Nile, and became familiar with the 

 quarries in that locality, they could see the origin of these won- 

 ders of the lower Nile. So time-enduring were these rocks, that 

 holes drilled in them for the purpose of cleaving blocks, remained 

 almost as perfect as when the workmen abandoned their labors. 

 Slabs of this material were partly finished. Although these 

 quarries were abandoned nearly three thousand years ago, the 

 remark was made that you now see where the workmen left off 

 laboring. In taking a more enlarged view of a river in moun- 

 tainous districts, as the Hudson for instance, we can see that its 

 cataracts have formed a deep channel from its mouth to Glen's 

 falls, where the waters for the time being seem to have left off 

 their labors. The same remark cati be made of the Mohawk river 

 at the Cohocs, of the West Canada creek at Trenton. The same 

 phenomena are seen in almost every river and rivulet on the face 

 of the earth. The proof that rivulets or tributaries have worn 

 their channels from the river valley, becomes more apparent from 

 the fact that the kind of material of which their banks are com- 

 posed, is carried onward toward the river, and most frequently 

 turns its channel to the opposite bank. 



Before going into a detailed statement of the changes that have 

 taken place on the surface of the earth, we will state the order or 

 laws by which new formations are made. Every body whether 

 animal, vegetable or insect is formed from the elements of pre- 

 existent bodies, and necessarily implies a transposition of matter. 

 The tree although it grows out of the earth without any per- 

 ceptible diminution of the soil, yet nevertheless derives its sub- 



