168 The American Geologist- March, isgo 
of that Virginian flora do not render justice to the beautiful 
specimens of those fossil plants. The descriptions are gen- 
erally good ; only the reference to species and even to genera 
may be improved, as has been shown by professor Zeiller of 
the School of Mines, of Paris, and by Mr. D. Stur, the director 
of the geological survey of Austro-Hungary. 
The paper of director Stur {loc. cit.) is a very important 
and just review and criticism of professor Fontaine's mono- 
graph. Without entering into details, I shall only remark, 
that to mj^ great satisfaction, director Stur refers the very 
common Equisetum of Virginia to the Eq. arenaceum of the 
vicinity of Stuttgart, as I did in 1849; and also the very 
abundant and characteristic Calaniites to Cal. meriani of 
the Swiss Keuper, According to Mr. Stur's careful determi- 
nation of the specimens of Virginia put into his hands by the 
director of the United States geological survey, several of the 
species named by professor Fontaine pass into sj'nonymy, 
having been described by Brongniart, Jaeger, Kurr, Heer and 
Stur. From the tables published by Messrs. Fontaine and 
Stur, showing the names of the Virginia plants and their 
affinities, it is certain that we have there a Keuper flora, well 
characterized, representing and the equivalent of the Letten- 
kohl flora of Lunz and Raibl. As the plants in Virginia range 
and are distributed all over the one thousand feet thickness 
of the upper strata, being more concentrated, however, at 
about seven hundred feet below the superior sandstone, just 
as in southern Tyrol, we can say, without the least doubt, that 
the coal fields of eastern Virginia are the equivalent of the 
whole Keuper of Europe, and that the flora represents the 
flora of the Lettenkohl of Germany, as Emmons said as far 
back as 1852, using exactly the same name of LeiteiiTiohl in 
his first report of the geological survey of North Carolina. 
Professor Fontaine thinks the Virginia flora is not older than 
Rhsetic. That is to say, that the coal series of Richmond 
belong and are the equivalent of the Rha3tic formation of 
Europe. The Rhfetic is simply the '•'■ Avicula contorta zone ^^^ 
or Infra-Lias, or third division of my superior stage of the 
Keuper of the "Jura Salinois ;" the color and uppermost type 
of the Trias ; an extremely limited subdivision of the fifth 
order, whose average thickness in central Europe is only 
twenty to thirt}^ feet, while in Virginia and North Carolina the 
