Reviews — Sun Pictures of Bocky Mountain Scenery. 173 



time to time attempt their arrangement under some system or theory. 

 If we could insure our possessing every single fact of the case, 

 such a theory or system could not be other than the true one ; for 

 knowing all the facts, we should be able to correct it and test its 

 accuracy. So long, however, as we have not arrived at such a 

 desirable consummation, it must nevertheless be admitted that 

 science may be benefitted by occasionally attempting — as in the 

 present instance — to bring all the facts already obtained under 

 some systematic hypothesis, even if this be regarded as but a 

 temporary arrangement and subsequently found to require much 

 modification in order to accommodate itself to the advances of our 

 knowledge of the subject. 



lazEj-sruE-vsTS. 



I.^Stjn Picttjbbs of Eocky Mountain Scenery; with a Descrip- 

 tion of the Geographical and G-eological Features, and some 

 account of the resources of the Great West ; containing Thirty 

 Photographic Views along the Line of the Pacific Eailroad, from 

 Omaha to Sacramento. By P. V. Hayden, M.D., U.S. Geologist, 

 Professor of Mineralogy and Geology in the University of 

 Pennsylvania. Quarto, pp. 158, with 30 full-page Photographs. 

 (London : Triibner & Co., 8 and 60, Paternoster Kow.) 



THE construction of the Pacific Eailroad led to the production of 

 a series of fine photographic views by Mr. A. J. Eussell, of 

 New York, who spent more than two years along the line of road in 

 the employ of the Union Pacific Eailroad Company. From these 

 photographs thirty have been chosen, mainly with a view to the 

 illustration of some special feature of physical geography and geology, 

 to which Dr. F. V. Hayden has contributed 158 pages of excellent 

 descriptive text. 



The district chosen for illustration in these sun pictures commences 

 with the first range of mountaias west of Cheyenne, and continues 

 thence to Salt Lake City, thus serving as an illustrated guide to 

 those who may desire to study those grand geological features which 

 the Pacific Eailroad opens to enterprising tourists. 



Prior to the travels of Lewis and Clark in 1803 and 1804, it was 

 supposed that the Eocky Mountains formed a single ridge, extend- 

 ing from north to south ; or at least of one main range, with a few 

 minor ranges. We now know that this name includes an almost 

 limitless series of ranges of every variety of form. From the eastern 

 slope westwards, we pass over range after range for a thousand miles 

 or more, until we descend the western slope of the Coast Eange to 

 the Pacific Ocean. 



Dr. Hayden shows us how the features of the country have been 

 as it were developed. He points out that in proceeding westward 

 from the Missouri or Mississippi rivers there is a gradual ascent. 

 At first not more than one foot per mile, but steadily increasing 

 until we reach the base of the mountains, where the ascent is fifty 



