Revieivs — Haydeti's Atlas of Colorado, 365 



IV. — Geological and Gteographical Atlas of Colorado, and 

 Portion of Adjacent Territories. By P. V. Hayden, U.S. 

 Geologist-in-Charge. Published by the Department of the 

 Interior, under the United States Geological and Geographical 

 Survey of the Territories, 1877. 



WE have just received, through the agency of the Smithsonian 

 Institution, this grand contribution to the Geology of America. 

 Most of our readers are aware that a general survey of the very large 

 and important, though often very inaccessible areas, known as " The 

 Territories," was organized in the year 1867, and those who are 

 observers of American progress have watched with increasing in- 

 terest the vast advances which have been made in this Survey under 

 Dr. F. V. Hayden. Very few weeks have elapsed since we received 

 Vol. VII. of the Memoirs of the Survey, being a large quarto vol. of 

 370 pages and 65 plates, on the Tertiary Plants of the West, of 

 which another similar volume (VI.) formed the Cretaceous Flora. — 

 1877 saw the appearance of a very large volume on North American 

 Eodentia (for the researches of this all-embracing Survey are directed 

 to many subjects besides Geology), while a year or two before we 

 had a volume on the Cretaceous Vertebrata by Cope, illustrated with 

 57 beautifully executed plates. The Bulletin (of shorter papers) has 

 already reached the middle of Vol. IV. — In 1873, the work of 

 the Survey was systematically commenced in Colorado. And here 

 we have the results of four years' labour (1873-74-75-76) produced 

 and published in a finished state in the year 1877 ! 



And such four years of labour as these must have been ! an area 

 exceeding that of Ireland, in parts most inaccessible, everywhere diffi- 

 cult to travel in, open to disturbances, or fears of disturbance, from 

 unsettled Indian tribes, where everything had to be carried with 

 the observer, and he thrown entirely on his own resources, and 

 such limited aid as he could bring with him ; such an area has been 

 triangulated, measured, physically examined, and mapped ; its drain- 

 age carefully determined, its economic and agricultural divisions 

 noted, and its geological structure carefully investigated. 



We have no hesitation in saying that Prof. Hayden may justly 

 point to this as a success, rarely ever approached, probably never 

 equalled. And may justly recount with pride the names of those 

 few who have so ably and so untiringly carried out his wishes. 



The Atlas consists of twenty sheets of large double elephant size. 

 These are in two series : first, of 4 sheets, which are general, and em- 

 brace the entire area on a scale of 12 miles to one inch. These show 

 (1) The Triangulations, (2) The Drainage, (3) Economic Map, (4) 

 General Geological Map. The second series consists of 12 sheets,. 

 in pairs, six representing (plain) only the topographical features of 

 different parts : N.W., N., Central, W., S.W., and S. Central Colo- 

 rado. And six sheets exactly corresponding, on which the geologi- 

 cal lines and colours are given ; then there are two sheets of 

 geological sections, and two of panoramic views. The detailed 

 maps are all on the scale of four miles to the inch, and embrace each 

 2J degrees of longitude, and 1^ degree of latitude — thus covering 



