Leo Lcsquereux. — OrUm. 293 
expanded into a theor}^ which covers the oriiiin of Ijy far the 
Largest part of our valuable accumulations of coal. The 
theory, variously supported and reinforced by American facts 
though not without grave difficulties, holds decidedly the first 
place today among the theories of coal formation in the geo- 
logical world. 
But it was not in the theoretical subject of coal formation, 
many of the problems pertaining to which are difficult and 
perhaps for the present insoluble, that Dr. Les(iuereux's great 
Avork was to be done. It is the plants, high and low, that have 
covered the earth in the past, and especiall}^ those assemblages 
of them which we denote coal floras, that were to be illustrat- 
ed by his patient labor and illuminated by his wide and in- 
creasing knowledge. Attached to the descriptions of a great 
number of these fossil plants, including many of the most 
abundant and important of the most valued floras of all time, 
the cabalistic letters "Lsqx." will remain as long as paleonto- 
logical science is cultivated. Dr. Lesquereux's labors covered 
the great Appalachian coal field, as it occurs in a half dozen 
states, and from the bottom of the series to its summit. Equal- 
ly fruitful were his studies of the floras of the later coals. 
The most valuable single contribution that he has made to 
paleobotany is unquestionably "The Coal Flora of Pennsyl- 
vania", published by the Second Geological Survey of that 
state. There is no other American work on the subject that is 
even to be named in comparison with it. It was written when 
the venerable author had long passed his three score years and 
ten, and Avhile embodying all his knowledge and experience, it 
shows no signs of flagging strength or failing powers. A list 
of his most important contributions to science will be given at 
the close of this paper. It stands for a prodigious amount of 
labor of the highest grade, accomplished under the fearful dis- 
advantage of total deafness. 
For the last forty years, the name of Leo Lesquereux has 
been known and honored throughout the scientific world. He 
was made a member of a score of the leading scientific socie- 
ties of Europe and was the first elected member of the Nation- 
al Academy of Sciences, of the United States. In 1875, he re- 
ceived the degree of Doctor of Laws from Marietta College. 
He maintained intimate relations by a constant and most kind- 
ly correspondence with all the leading paleontologists of Eu- 
