Mr. J. Boaz on the Si rue tare of the Earth, Sfc. 201 



conspicuous ; as well as the many extensive caverns of vast 

 dimensions, through which water having found a passage has, 

 in the course of ages, worn down, dissolved and cai-ried off 

 those materials which otherwise would have accumulated and 

 entirely filled them. 



In other cases, after every corner of every cavity has been 

 filled or cemented, we see the effects of fresh disruptions, de- 

 nudations, and separations of materials, and subsequent fillings 



"P- ... 



In all the classes of animal and A-egetable bemgs, it is easy to 



know, by their appearance, nearly the length of time they have 

 existed ; but, except in the instances in which we surprise na- 

 ture at work in her laboratory, in the art of repairing, by her 

 liquid petrifactive solder, the ghastly fissures and fractures of 

 the shell we inhabit, it is impossible to ascertain the age in 

 which any of these masses assumed their present shape. 

 When however we see that a rock has been cracked and ce- 

 mented, it is reasonable to conclude that the mending has 

 been a subsequent operation to that of the formation. Again, 

 when we see stratified masses of equal thickness having a de- 

 clination of 4-5 degrees, we may rest assured that these masses 

 are not reposing in the situation in which they were originally 

 formed: for, were a flat level field to be covered over with 

 fluid mud, it would, on drying, form a stratum of nearly equal 

 thickness throughout : — on the other hand, if the same mud 

 had been deposited on the side of a mountain, the stratum 

 would be shallow high up, and deeper at the bottom. In some 

 parts of the world, we see immense chains of Viigh mountains 

 composed of matter stratified in every direction from the dead 

 level to the vertical. These also we may fairly conclude were 

 not originally so. 



Every mountain, whether of soft or hard materials, has a 

 tendency by the gravity of its particles to find a lower situa- 

 tion. The mouldering tooth of time, aided by frosts, rains, 

 winds and chemical afhnities, fritters away the most flinty pre- 

 cipices, and pulverizes them so sufficiently as to be blown down 

 by every breeze, or washed and floated away by innumerable 

 currents of water to the great receptacle, the ocean, and there 

 deposited, in stratum super stratum, often at immense depths, 

 until an event shortly to be mentioned brings them up again 

 to the face of day. 



In Holland, the lowest of all low countrie.s, excavations have 

 been made several hundred yards deep, aiul nothing but beds 

 of alluvia found. The highest lands, — Quito, the Andes of 

 America; the Ilinii'ila mountains in Asia, still higher; and 

 othcr.s, on all of which marine debris has been found, — must 



Vol.61. No. '299. March 182.3. C c one 



