30 REVIEWS CLIMATOLOGY OE THE UNITED STATES. 



the Eocky Mountains ia also given, arranged in meridional belts 

 5° in width from the 100th meridian westward. 



In instituting a comparison between the old and new worlds, with re- 

 spect to their physical geography, the author considers that there are 

 features now sufficienly apparent in North America which hitherto 

 have been considered as peculiar to the older continents. 



" The great point of interest lies iu tlie new features of our physical geography, 

 or in the views which differ so far from those previously held, as to require a change 

 in all deductions based upon surface and vertical configuration, as ail those of 

 climatology must be to some extent. The most important of these recent deter- 

 minatious is that of a much greater altitude for the western interior than was be- 

 fore assigned to it, and that high and arid plateaus and basins exist in nearly as 

 great a proportion to the general area of the continent as in Asia and Europe. 

 There are conditions of surface and configuration similar to those which have been 

 thought peculiar to Europe and Asia belonging to great regions here, and -^e are 

 to look for correspondence in climate, and in vegetable and animal life, and if this 

 last does not now exist, we ascertain such a correspondence to be possible, and 

 may adapt our practical interests accordingly. Guyot, and other writers on phy- 

 sical geography, have contrasted the temperate latitudes here with those of Europe 

 and Asia, in the view that this is wanting in the high desert plateaus of these, and 

 assuming for this less altitude, a greater proportion of plains, and, consequently, 

 the analogies of sea climates in contrast with the extreme continental peculiarities 

 of Asia. Our recent surveys have shewn that lofty plateaus, lofty mountains, and 

 extended districts of the most extreme continental character, exist here in nearly 

 the same relation to the whole miss of the continent as in the old world, and the 

 comparison of the two thus becomes much more direct and more necessary than 

 before, as essential to a proper understanding of our climatology. In short we 

 may compare the two as mainly equal and similar in the physical features of sur- 

 face and configuration, and we must do so to correctly estimate the consequences 

 upon climatology, which are always most directly dependent on physical geography." 

 pp. 84, 85. 



The Alleghanies have been often considered as forming a line of 

 demarcation between two very different elimatological areas : it would 

 seem, however, from more recent investigations, that the elevation 

 of these mountains has but little influence in interrupting the uni- 

 formity of climate, excepting in the moderate degree produced by 

 altitude alone, and that it is the Rocky Mountains that we must re- 

 gard as the true barrier between two regions climatologically distinct. 



"The great chain of the Rocky Mountains is next in the surface configuration, 

 and from this point forward aH the uniformity belonging to the Eastern United 

 States disappears, and the greatest and most abrupt contrasts occur. As in the 

 north of India and in other parts of Asia, everything here depends on configura- 

 tion and surface ; and not only on these directly, but also on the relation of any 

 point or locality to an extreme of configuration in the vicinity. Thus the valleys 



