826 PICTURESQUE SKETCHES 



distances from the parent rock, are facts distinctly 

 made out. Such blocks, also, are not confined to 

 northern Europe, but are met with both in North 

 and South America, and in other parts of the world. 

 It is, however, certain, that true gravel with rolled 

 blocks of stone is not universally distributed; and the 

 effects thus produced have been as partial as they 

 were frequent, the result being often quite different. 

 It thus happens that while in most cases common 

 gravel, or transported and erratic blocks and boul- 

 ders, have been deposited, we find elsewhere only 

 great masses of mud and clay, mixed with stones, 

 sand, or any other material, drifted into recesses, and 

 left there by the iceberg or the retiring wave. 



It is not likely that a great system of eleva- 

 tion can have acted during a long period, bursting 

 asunder in some districts the hard and brittle rocks 

 at the surface, and sending up granite in a soft and 

 pasty or melted state ; tearing asunder in others the 

 tough superficial beds, and allowing the escape of 

 gaseous vapours and currents of molten rock ; while 

 in others, again, wide tracts were slowly but per- 

 manently lifted above their former level, without 

 a re-action having taken place after the force had 

 ceased to act, causing a general or partial subsidence 

 over some vast areas. Possibly, the more extreme 

 and Arctic temperature which many things seem to 

 indicate as characterising a late geological period, 

 may have been connected with a more uniform ex- 

 panse of land near the poles, the general level of 

 that land being also somewhat higher than at pre- 

 sent. After this partial elevation there may also 

 have been a partial depression, especially, perhaps, in 



