474 Mr. Hopkins on the Elevation and 



Modes of Transport — Glacial Theory. — This theory, in its appli- 

 cation to the transport of blocks across Stainmoor, involves such 

 obvious mechanical absurdities, that the author considers it totally 

 unworthy of the attention of the Society. Polished and striated rocks 

 were, however, detected by Dr. Buckland, and pointed out by him 

 to the author in various places. The author does not feel himself 

 called upon to offer any decided opinion as to the cause of such 

 phaenomena ; he here speaks of the glacial theory only with re- 

 ference to the solution it offers of the problem of the transport of 

 blocks or detritus to distant localities. 



Iceberg Theory. — There appears to be no doubt that floating ice 

 may have played an important part in some cases in the transport 

 of large blocks, but the author doubts whether such agency has been 

 at all employed in the case under consideration. In the first place, 

 he cannot but consider it absurd to attribute the formation of a bed 

 of diluvium spread out with approximate uniformity over an extended 

 area to the action of floating ice. Such a distribution of the trans- 

 ported matter is the necessary effect of broad currents of water, 

 which, at most, is the merely -possible effect of floating ice. Se- 

 condly, there appears no adequate reason why blocks transported 

 by floating ice should diminish in size as their distance from their 

 original site increases ; why the Cumbrian blocks on the eastern 

 coast of Yorkshire should be generally much smaller than those less 

 remote from the place whence they came. Thirdly, the theory in 

 its application to the case before us involves a great physical diffi- 

 culty — a depression of temperature, for which no adequate cause 

 has yet been assigned. The author does not admit the parallel 

 which has been drawn between this case and that of places in equal 

 latitudes in South America or that of the island of Georgia. 



Transport by Currents of Water. — It has already been remarked 

 that the spreading x>ut of diluvial matter into a horizontal stratum 

 may be regarded as the necessary consequence of broad general 

 currents, and that this has been the agency by which the mass of 

 diluvium covering the surface of Lancashire has been carried there 

 does not admit, in the author's opinion, of the smallest doubt. He 

 accounts for the existence of currents diverging from the centre of 

 the district in question by a repetition of paroxysmal elevations. 



Suppose a certain area at the bottom of an ocean to be suddenly 

 elevated ; and, for the greater clearness, suppose the elevated area 

 to be a circle of twenty miles in diameter, its elevation to be 50 

 feet, and the depth of the ocean 300 or 400 feet. If the elevation 

 were sufficiently gradual no sensible wave would result from it, but 

 if it were sudden the surface of the water above the uplifted area 

 would be elevated very nearly as much as the area itself, and a 

 diverging wave would be the consequence. Its front would be steep, 

 like that of the tidal wave in some rivers called the bore, so that the 

 highest part or summit of the wave would not be far from its front. 

 The height at its summit would be approximately equal to the ele- 

 vation of the uplifted area, or, in the case supposed, nearly 50 feet. 

 The velocity with which the front would diverge would depend on 



