LEO LESQUEREUX. 323 



fossil plants. The material thus amassed was elaborated slowly and 

 cautiously, and with the maturity of years resulted in an astonishing 

 number of volumes, which towards the close of his life followed one 

 another in rapid succession, and we are told that there are still other 

 volumes awaiting publication. 



His first paper on fossil plants of America was apparently the one 

 entitled " New Species of Fossil Plants," in the Boston Journal of 

 Natural History of 1854, and there soon followed reports on the fossil 

 plants in the Geological Surveys of Pennsylvania and Kentucky 

 (1857), and later in the Surveys of Indiana, Illinois, and Arkansas, 

 and the National Surveys of the different Territories. Work on 

 mosses was gradually abandoned, as the work on fossil plants became 

 more and more absorbing. In the opinion of experts his most impor- 

 tant contribution to palaeontology was " Description of the Coal Flora 

 of the Carboniferous Formation in Pennsylvania," in the Second 

 Geological Survey of that State. It appeared in 1880, and showed 

 to what a remarkable extent he had retained his mental vigor un- 

 impaired, notwithstanding his infirmity and the hardships to which he 

 was subjected until he reached middle life. His pala^ontological work 

 was largely descriptive, and the number of new species of which he 

 was sponsor is very great. But in the long list of his published 

 works are to be found a considerable number in which he treated his 

 siibject in a general and philosophical way. Although his investiga- 

 tions were by no means limited to the coal measures, it is fair to say 

 that his writings show a preponderance of those in which he either 

 described plants from the coal formations or discussed in a general 

 way the origin of coal and the accompanying and resulting phenomena. 

 His early observations at Neuchatel had made him intimately ac- 

 quainted with the conditions under which, at the present day, peat is 

 formed, and the surmise of Brongniart, that in past ages coal might 

 have been formed under similar conditions, turned out to be in the 

 reflecting mind of Lesquereux a suggestion rich in practical results 

 as well as in theoretical speculations. Lesquereux was not the author 

 of any works intended primarily for instruction, although his paper on 

 "Principles of Palaeozoic Botany," in the Geological Report of Indiana 

 of 1884, might well be called an educational treatise. 



In Lesquereux we have a remarkable instance in which intelli- 

 gence and industry succeeded in overcoming both physical infirmity 

 and depressing surroundings. Although during his long scientific 

 career he was never able to take part in conversation, he was free 

 from the moroseness often found in the deaf, and, on the contrary, 



