Ruschenberger.] J. ID [Nov. 6, 



His report of the geological reconnoissance was presented 

 January, 1836. A note on the fertilizing efficacy of marl, taken 

 from the report of Henry D. Rogers on the Geology of New Jer- 

 sey, and a plan of the proposed Geological Survey of Virginia 

 are appended to it. Reports of the progress of the survey were 

 made annually from 1836 to 1841. It was discontinued in 18-12. 

 All his brothers were among his assistants in field and laboratory 

 work. 



He, as well as his brothers Henry and Robert, participated in 

 the organization of the Association of American Geologists and 

 Naturalists in 1840, and presided at the meetings of 1845 and 

 1847. At the latter it was changed to the American Associa- 

 tion for the Advancement of Science. 



At the meeting held in Boston, in 1842, he presented, in con- 

 nection with his brother Henry, a paper on The Laws of Structure 

 of the more Disturbed Zones of the Earth's Crust, embracing 

 what is called the wave theory of mountain chains. This theory 

 was a result of an extensive study of the Appalachian chain in 

 Pennsylvania and Virginia, and was supported by reference to 

 many geological sections and facts. They were first to assert 

 that the structure of mountain chains everywhere is the same in 

 all essential features, an assertion which has been confirmed by 

 the observations of Murchison in the Ural mountains, and by 

 Darwin in the Andes. 



The meeting was memorable. Dr. Samuel George Morton 

 presided. Among the distinguished naturalists present were the 

 elder Silliman, Professor Hitchcock, Dr. Charles T. Jackson, the 

 French astronomer, Nicollet, Sir Charles Lyell, and the palaeon- 

 tologist, Hall. Several able and elaborate essays were read and 

 discussed, but the prominent feature of the meeting was the 

 Rogers paper, which was delivered as an oral statement. William 

 B. Rogers first described the physical structure of the mountain 

 chain extending 1500 miles, from Vermont to Alabama, and then 

 Henry D. Rogers followed, explaining the phenomena and ex- 

 pounding the hypothesis deduced from them. 



John L. Hays, of Cambridge, Mass., who was present, says, 

 June 1, 1882: ; ' I have frequently read it [the paper] since. 

 To me it is now comparatively tame in expression. It lacks the 

 inspiration of the scene and the man, the illustrative diagrams, 



