FOSSIL PLANTS. 
491 
The shale of the coal at Morris and the concretions of Mazon creek have 
furnished also a number of specimens of three species, or rather forms, of 
Palceoxyrn , a kind of organism which is considered by Brongniart, Schimper, 
and other naturalists, as a plant belonging to a higher class of the vegetable 
kingdom, that of the monocotyledonousphoenogomous plants. In describing these 
bodies, I have expressed my views on their nature. If the opinions of the Eu¬ 
ropean authors are right, we have already, from the lower part of the Coal 
Measures of Illinois, vegetable organisms of a class of plants, whose first ap¬ 
pearance has been marked in the Triassic period. Though it may only effect 
their generic affinity, the presence of these bodies in the concretions of Mazon 
creek is the more remarkable that they are there associated, as in the Permian 
of Europe, with a quantity of animal remains, especially insects of large size, 
which have, as yet, not been discovered elsewhere in the Carboniferous for¬ 
mations. 
There has been found in the Coal Measures of England and Nova Scotia, 
specimens of fossil wood, referable by their tissue, a compound of large woody 
cells or fibres, marked by vertical circular spots, to the Conifers or Pine family. 
It is remarkable that most of the fossil wood of our Devonian strata indicates 
the same characteristic form of cells, and that as yet, neither in Illinois nor in 
other parts of our true Coal Measures, no kind of branches, leaves, or petrified 
wood distinctly related to this order of vegetables, have ever been observed. 
The fragments described from a nodule of Mazon creek in vol. 2, p. 447, pi. 
xxxvii, fig. 3, of this Pteport, under the name of Lycopodites astcropliyllitsefo- 
lius, resembles, indeed, a branch of some kind of Conifer, but it is as well com¬ 
parable to some species of Lycopodiacese. We have also obtained from the 
lower strata of the Coal Measures of Illinois and of Pennsylvania, specimens 
of Artisin transversa, Sternb., a species whose affinity is still uncertain, it being 
considered by Dawson a Conifer, while most of the European palaeontologists 
describe it with the Lycopodiacese. Our specimens are all transformed into 
sandstone, with no other part preserved but the mold, do not afford any light 
on this question. From this uncertainty as to the true affinity of these vege¬ 
table remains, and what is said above concerning other orders of fossil plants 
found in the Carboniferous strata, it would seem proper to conclude that the 
flora which has furnished the materials for the formation of our coal, and which 
covered the bogs of our continent at the Carboniferous epoch, was limited to a 
single group of vegetables, that of the acrogenous cryptogams. (1) The same 
(1) Prof. Goppert considers the genus Sigillari'a as rather related to a gymnospcrm family. 
Its relation with the genus Lepidodenclron is too evident to permit this conclusion; the cones 
and seeds of Sigillana have moreover been found in our Goal Measures, of the same charac¬ 
ter as those described by Goldenberg. 
