534 PROCEEDINGS OF THE SAINT LOUIS MEETING 



" good, bad, and indifferent," and laid down the foundation colors. This 

 done, he constructed thirteen cross-sections and drew to a scale several 

 hundreds of local sections, diagrams, and sketches, the whole work 

 occupying eighteen months of 1842 and 1843. 



Having completed his theological course, Lesley was licensed to preach 

 by the Presbytery of Philadelphia in 1844 and at once went to Europe, 

 where he made a pedestrian tour through France and Germany, which 

 he closed with a brief course of study at the University of Halle. Return- 

 ing to America, he undertook col portage work in northern Pennsylvania 

 for the American Tract Society, which he pursued with characteristic 

 energy and success for two years. In December, 1847, Professor Rogers 

 asked him to come to Boston, where for five months he was busy in pre- 

 paring duplicate copies of the geological map and sections, which were 

 to be placed in the state capitol at Harrisburg. While in Boston he 

 received and accepted a call to the pastorate of the Congregational 

 church at Milton, Massachusetts, where he remained until 1851. In 

 this interval his views respecting some theological matters developed 

 along lines not wholly acceptable to his ministerial associates, so that at 

 the end of four years he resigned his charge, abandoned the ministry, 

 and returned to Philadelphia, where he began to practice as consulting 

 geologist. At once his services were sought again by Professor Rogers, 

 who had obtained an appropriation for preparation of the final report, 

 and for more than a year he was engaged upon the revision work. 



Thenceforward for forty years his labor was incessant. He was recog- 

 nized at once as the most competent of geological experts, and his time 

 was fully retained. Yet from 1855 to 1859 he was secretary of the Amer- 

 ican Iron Association, for which he published in 1859 a huge volume, 

 the "American Iron Manufacturers' Guide," a remarkable compendium 

 of theory, practice, and statistics, which even now is of much value. 

 From 1858 to 1885 he was secretary and librarian of the American Phil- 

 osophical Society, rarely absent from its meetings and seldom failing to 

 present a paper or to take part in the discussions. He made elaborate 

 surveys of the Cape Breton coal field, of the Pennsylvania coke region, 

 of the Broad Top area, of the Cumberland Valley iron ores, and of many 

 other areas outside of his own state, and besides found abundance of time 

 in which to learn several languages and to prosecute special studies in 

 several departments of literature and philosophy. In 1872 he was made 

 professor of geology and dean of the faculty of science in the University 

 of Pennsylvania, but in 1878, owing to the pressure of other duties, he 

 resigned the deanship. The Second Geological Survey of Pennsylvania 

 was authorized in 1874, and he was placed in charge of the work, which 

 he conducted until compelled by failing health to relinquish it, in 1895. 



