Review of the Glacial Tliforij. 261 



were causes in activity of greater inteimty or more wonderful in their 

 character, than those now in operation. If geology, as a science, 

 tends to demonstrate anything, it is uniformity in the laws of nature. 

 There are no mysterious agencies, and there have never been any in- 

 terruptions of the uniform laws of change. Continents are not now 

 lifted up or depressed ; they never have been. Such phenomena are 

 physically impossible. 



This continent is now elevated but a few hundred feet above the 

 level of the ocean, and yet it has been forming through all geological 

 time, even from the remotest. First, we had in Eozoic days an island 

 in British America; next, in Silurian ages, several islands; then an 

 archipelago marked the Devonian era ; finally, the islands were con- 

 nected together during the Carboniferous ages, at the close of which 

 the eastern part of the continent took its present form ; and later, 

 during tha Cretaceous and Tertiary periods, the southern and western 

 outlines became fixed. Thus, from the very earliest geological periods 

 to the present time, this continent has been forming. Deposition has 

 been in active operation all the time, and this has been assisted from 

 time to time by active earthquake phenomena. The most remarkable 

 earthquake elevations in modern centuries have been in Chili, where, 

 it is said, a narrow strip of land one hundred miles long was raised 

 three feet high during a single earthquake, but in that inhospitable 

 region such an earthquake is not liable to occur once in a century. 

 Such earthquakes are mountain makers. Such earthquakes in. thou- 

 sands of centuries formed the Alleghenies and the other ranges of 

 mountains on this continient. They have stamped their characters 

 upon their work too legibly to be misunderstood. No power has lifted 

 up continents, and no force sufficient to do it exists in nature. 



A theory, having its inception in an impossibility, may be expected 

 to be clothed with extravagant hypotheses, and so we find this one, 

 for the next step is not a sequence of the first, but an independent 

 statement, that there was an Arctic climate all over Ohio, Indiana 

 and Illinois, while on the mountains of Virginia and Kentucky the 

 climate was not materially different from what it is now. It was 

 intensely cold over the central part of the continent, and warm and 

 pleasant on the mountains on the border, so that the clouds of vapor 

 could readily pass over the mountains, and " wherever there was a 

 copious precipitation of moisture from oceanic evaporation that mois- 

 ture fell as snow." From this arrangement " a great ice sheet moving 

 from the north northwest covered all New England, and other glaciers 

 occupied the regions east of the Mississippi and north of the Ohio." 



Are we to believe that the continent was elevated sufficiently to 



