SCIENCE. 



[N. S. Vol. V. No. 105. 



carried on at Cumberland, and at various 

 points between there and Wheeling. He 

 also remarks upon the Blowing Springs, 

 and said he had no opportunity of testing 

 whether they sent out gas or only air. He 

 frequently mentions fossils observed, encri- 

 nites and productus, but does not attempt to 

 define geological horizons by them, but only 

 to judge whether the limestones were primi- 

 tive (without organic life), transition or 

 secondary. 



1832. In 1832 Mr. Schoolcraft, under a 

 commission from the government, com- 

 manded an expedition to the country about 

 the sources of the Mississippi Eiver, which 

 he discovered took its rise in Lake Itasca, 

 a narrative of which was published in 1834, 

 and again enlarged in 1855. 



1832-6. The expeditions of Capt. Bon- 

 neville, U. S. A., made famous by Irving's 

 two narratives, were not, strictly speaking, 

 government expeditions, being conducted 

 under the auspices of the American Fur 

 Trading Company, while he was on leave of 

 absence from the army. No geologist was 

 attached to the expedition, but the geographi- 

 cal results were very important, as by them 

 was first determined the enclosed nature of 

 the great interior basin, which had hitherto 

 been supposed to have an outlet to the 

 Pacific Ocean through the mythical Rio 

 Buenaventura. 



1834-5. G. W. Featherstonaugh, of 

 whose origin little seems to be known ex- 

 cept that he was a foreign traveler, was 

 employed by Lewis Cass as Secretary of 

 War, during the years 1834-5, to make geo- 

 logical investigations in the Ozark Moun- 

 tains and along the elevated plateau sep- 

 arating the Missouri Eiver from the St. 

 Peter, or Minnesota River, known as the 

 Coteau des Prairies. The report upon the 

 first of these regions was published in 1835, 

 and that upon the second in 1836. 



In Featherstonaugh's time, light was 

 commencing to come to the minds of Ameri- 



can geologists out of the obscurity of ideas 

 concerning the existing division of rocks 

 into primitive, transition and secondary. 

 It was already practically recognized that 

 different horizons could be correlated in 

 different parts of the world more safely and 

 accurately by fossils than by lithological 

 characters. Featherstonaugh found Car- 

 boniferous fossils widespread throughout 

 the United States, on which he makes the 

 following comments : " Although these fos- 

 sils are not identically the same as their 

 equivalents in Europe, yet many of them 

 are strictly so; and in all cases I would as- 

 sert the generic resemblances to be stronger 

 than the specific differences. On this con- 

 tinent, where the Carboniferous limestones 

 extend uninterruptedly for more than 

 1,000 miles, we find an equal amount of 

 generic resemblance and specific difference, 

 and it is certain that the specific difference 

 between the most powerful species of living 

 animals here and those in trans-Atlantic 

 countries seems to be much greater than 

 that which prevails among fossils of the two 

 hemispheres." With regard to what had 

 been generally known as primitive or inor- 

 ganic rocks, however, he is not willing to 

 accept the Wernerian or Plutonic theory of 

 origin. Their differences with each other, 

 except statuary marble, he remarks, result 

 only from a difference in proportions of cer- 

 tain mineral constituents, which gives rise 

 to the opinion that they had a common 

 origin and " that they have all at some 

 period been either ejected from central beds 

 by the expansive power generated there, or 

 that they have been great intumescing 

 masses which on cooling have resolved 

 themselves into various stages of crystalliz- 

 ation, and that their varying products have 

 been brought by fusion or solution into 

 distinct central localities." 



In his report Featherstonaugh publishes 

 a section 12 feet long, extending from the 

 Atlantic Ocean to Texas, which presents a. 



