298 Apparent objections to the Glacial Theory. 



of it was a triangular piece of granite, about a yard in diameter, 

 resembling in composition the red granite of Finland." " In a late 

 voyage of discovery made in the antarctic regions in 1839, a dark 

 coloured angular mass of rock was seen imbedded in an iceberg, 

 drifting along in mid-ocean in lat. 61° S." — Prin. Geol. p. 370- 

 379. 



These instances are sufficient to show, that modern icebergs are 

 instrumental to the deposition of angular boulders, and that although 

 they also carry large quantities of rounded pebbles and blocks, yet 

 the probability is in favour of these latter having been uplifted from 

 districts previously strewed over with the water- worn detritus of a 

 former epoch ; while therefore the true ancient erratics are rounded, 

 the modern iceberg deposits, if composed of fragments recently 

 torn from rocks in situ are angular or possessing their sharp edges ; 

 it still remains then to account for the rounding of ancient erratics. 



It has often been objected, that the transient passage of a body 

 of waters over the land could not have imparted to transported 

 matter, the rounded and often polished surface which its pebbles 

 and boulders exhibit ; but there are conditions attending the de- 

 position of ancient erratics, to which due weight does not appear to 

 have been accorded. The sharp and rugged outline almost invari- 

 ably apparent among members of the primary class, and the curious 

 step-like structure of the trappean rocks, to all of which an igne- 

 ous origin is now pretty generally assigned, have long since attract- 

 ed the attention of observers ; and controversies have occasionally 

 arisen as to whether molten or fused matter could have assumed the 

 acute and steeple-shaped form of granitic peaks ; or whether it 

 ought not rather to have arranged itself over the surface after the 

 manner of modern lavas. The fact, that at the time when primary 

 and plutonic rocks were upheaved, the strata of the earth were 

 horizontal beds beneath the deep enveloping waters of the sea, seems 

 to have been entirely lost sight of, or disregarded in these contro- 

 versies. If, however, we admit this fact, it must be evident, that 

 when the igneous rocks first burst through the upper strata of the 

 earth, and came in contact with the cold waters of the superincum- 

 bent ocean, a sudden cooling and contraction of the heated mass 

 must naturally have ensued, which would have caused the surface to 



