42 VESTIGES OF THE 



Tlie interior of the globe has now been inspected in 

 this way in many places, and a tolerably distinct notion 

 of its general arrangements has consequently been 

 arrived at. It appears that the basis rock of the earth, 

 as it may be called, is of hard texture, and crystalline in 

 its constitution. Of this rock, granite may be said to be 

 the type, though it runs into many varieties. Over this, 

 except in the comparatively few places where it projects 

 above the general level in mountains, other rocks are 

 disposed in sheets or strata, with the appearance of 

 having been deposited originally from water. But these 

 last rocks have nowhere been allowed to rest in their 

 original arrangement. Uneasy movements from below 

 have broken them up in great inclined masses, while in 

 many cases there has been projected through the rents 

 rocky matter more or less resembling the great inferior 

 crystalline mass. This rocky matter must have been in 

 a state of fusion from heat at the time of its projection, 

 for it is often found to have run into and tilled up lateral 

 chinks in these rents. There are even instances where 

 it has Ijeen rent again, and a newer melted matter of the 

 same character sent through the opening. Finally, in 

 the crust as thus arranged, there are, in many places, 

 chinks containing veins of metal. Thus, there is first 

 a great inferior mass, composed of crystalline rock, and 

 prol3ably resting immediately on the fused and expanded 

 matter of the interior \ next, layers or strata of aqueous 

 origin ; next, irregular masses of melted inferior rock 

 that have been sent up volcanically and confusedly at 

 various times amongst the aqueous rocks, breaking up 

 these into masses, and tossing them out of their original 

 levels. This is an outline of the arrangements of the 

 crust of the earth, as far as we can observe it. It is, at 

 first sight, a most confused scene ; but after some careful 



