266 



THE WORLD. 



have existed in the places where it has left them. Indeed,', ne 

 proofs of elevation and subsidence, are everywhere too palpable to 

 be mistaken. Stratified rocks, or rocks deposited by the agency 

 of water, form the summits of the highest mountains, elevated 

 many thousands of feet above the level of the sea. In these 

 strata, the remains of shells, fishes, and other marine animals are 

 imbedded. When in addition to this, we observe these strata 

 not horizontal, but nearly vertical, we cannot resist the conclusion 

 that they have either been violently upheaved by some tremen- 

 dous convulsion, or gradually raised by the irresistable agency 

 of a long continued subterranean force. The evidence of dis- 

 turbance of the strata, afforded by certain marine worms is im- 

 portant, and is an instance of the subservience of the actions of 

 even the meanest of created beings, to the elucidation of truth. 

 It is well known that certain of these worms, inhabiting straight 

 and tubular shells, bore the sand in a vertical direction, as repre- 

 sented in this figure, and if the strata remained undisturbed the 



direction of the bore would be always vertical. But the shells 

 are found in various strata, making various angles with the hori- 

 zon according to the elevation of the strata, as shown in the K<r- 

 ure below, and occasionally, a more recent shell will have the 



vertical direction as at a, boring the cavity subsequently to the 

 elevation of the strata. Beds of pebbles, once deposited in reg- 

 ular horizontal strata, are found making angles with the horizon, 

 thus witnessing the same fact. 



We will now briefly consider some of the most remarkable 

 earthquakes which have occurred within the historic period. We 

 commence with the well known one which nearly destroyed the 



