AMERICAN GEOLOGY EATONIAN ERA, 1820-1829. 291 



was but little given to theorizing-, at least so far as is shown by his 

 published works, and announced few, if any, new principles. His 

 fame rests rather upon the extension of the geographic boundaries of 

 our knowledge and the development of economic resources. 



The matter of the relative age of rocks as indicated by their position 

 with respect to horizontal ity, which had been discussed by Cleaveland 

 in 1816, Maclure in 1825, and Jackson in 1828, was again taken up by 

 Vanuxem in 1829. In a paper in the American Jour- 

 vanuxem's Views, na j Q £ Science in this year he called attention to sev- 

 eral errors promulgated by the American geologists, 

 the first of which related to the existence of Alluvium and Tertiary 

 rocks in the Southern Atlantic States, as he had previously announced 

 in conjunction with Morton. 



Of almost equal importance was the objection raised at this time to 

 the prevailing assumption that all of the so-called secondary rocks 

 were horizontal in position, or, on the other hand, that all horizontal 

 rocks were, therefore, secondary. He pointed out that rocks com- 

 posed of mechanical particles when undisturbed would form horizon- 

 tally lying masses, but that both uplifting and downfalling forces had 

 existed and there was no certainty that such had acted in a uniform 

 manner, giving rocks of the same age the same inclination. There- 

 fore the position of beds as regards horizontal ity, he. argued, could 

 not be relied upon to indicate age. "The analogy or identity of 

 rocks," he wrote, "I determine by their fossils in the first instance 

 and their position and mineralogi-cal characters in the second or last 

 instance." This is perhaps one of the most important generalizations 

 that had thus far been made by any American geologist. 



Vanuxem was a Philadelphian by birth, but received his mineral- 

 ogies,] and geological training at the School of Mines in Paris at the 

 time when Brongniart and Hauv were both active. Graduating in 

 1819, he returned to America and assumed the chair 

 vanuxem. of chemistry in Columbia College, South Carolina, 



resigning in 1826 to undertake some private mining 

 work in Mexico. In 1830 he removed to a farm near Bristol, Penn- 

 sylvania, which continued to be his home during the rest of his life, 

 though connected with the New York State survey during 1837-13. 



He is represented as a man of slight build, active and energetic, and 

 with great powers of endurance; one who loved his work for the 

 work's sake, and was always averse to receiving pay for his services 

 excepting when circumstances rendered it absolutely necessary. 



According to his biographer, he had the reputation of being vision- 

 ary and full of untenable theories. Be this as it may, his published 

 writings show no such failing, and there are few men of his day who 

 saw more clearly or reasoned more correctly. His published writings 

 were, for that time, remarkably free from error. As a geologist he 



