GEOLOGY AND PALEONTOLOGY. 163 
group, their mode of deposition, etc., have been examined. From the facies and 
the peculiar distribution of the leaves, it is there admitted that the vegetable re- 
mains have been derived from trees or shrubs growing in the vicinity of marshy 
or muddy bottoms, and that they have been buried or fossilized at or near the 
place of their growth. This condition is based not only upon the remarkably 
good state of preservation of the fossil leaves, which are generally found hori- 
zontally flattened in the same plane or parallel to that of the deposition of the 
earthy matter, neither crumpled, rolled, nor lacerated, and with their borders, 
often even their petioles, attached to them, but also upon the distribution of the 
leaves, which at different localities generally represent different species, while at 
a short distance another group of leaves represent other species, genera, or even 
families. 
‘¢These remarks have been lately confirmed by the discovery in Ellsworth 
county, Kansas, of a very large number of leaves embedded in concretions. 
These concretionary specimens were found at more than twelve different locali- 
ties, in groups covering limited areas, the largest tract being about 100 yards, the 
others not more than seventy yards in width, altogether distributed over a land 
surface of five to eight square miles. The specimens of each locality were sepa- 
rately collected and were also determined separately, and each lot was found to. 
be composed of from one to three species, and few of them were represented in 
more than two or three localities. Thus, leaves of Sterculia were found in one 
locality ; at another, leaves of Greviopsis; in two or three others mostly leaves of 
Betulites were collected ; and in others leavesof Populus kansana, with Diospyrvs 
rotundifulia, etc. The leaves forming the nucleus of the pebbles are in a perfect 
state of preservation, a number of them with their pedicels, or even a small stip- 
ule at their base. Of course the fossilization of numerous leaves of the same 
species in groups, at various more or less distinct localities, gives positive evidence 
of their growth in that place, or at least quite near, where their remains have 
been fossilized. 
‘*As yet the relative altitude of the localities where the various groups of 
specimens have been found has not been fixed, and we do not know whether 
the diversity of the characters of the plants might not be accounted for by a 
difference in the horizon of the strata where they have been found, and therefore 
by a difference of age. Are there peculiar zones in the formation, which might 
be indicated by marked characters in the vegetation? No answer can as yet be 
given to the question. The concretionary specimens mentioned above have been 
found in the so-called highlands of Ellsworth county. But what are those high- 
lands as compared in altitude to the lowlands? Professor Mudge, who has 
closely searched for the distribution of plants in Kansas, did not find any differ- 
ence in the character of the plants that seemed to depend on the altitude of the 
hills. Near Salina I have found the same vegetable species distributed from 
the base to the top of the hills, the altitude being about seventy-five feet above 
high-water mark of the river. Hence, it is not possible as yet to consider a 
difference in the vegetation by peculiar zones like those in the Quadersandstein 
or Middle Cretaceous of Europe, where zones of the Liriodendron or those of the | 
Crednaria are mentioned as marking the relative horizons of the strata.” 
To this it is but necessary to add that later investigations have but corrobo- 
rated the conjectures of Doctor Lesquereux. Certain genera and species are 
confined to restricted localities, while others are found in widely separated re- 
gions. Proteoides daphnoganoides, for example, was one of the species de- 
scribed by Heer in his *‘ rhyllites”’; but it has since been found in nearly every 
locality and horizon throughout the group. Salia proteefolia is another form 
that is widely distributed. On the other hand, Betulites, Protophyllum, and 
many others, although very abundant in certain localities, have never been found 
elsewhere. Platanus, Sassafrasand Liquidambar have been found more abun- 
dantly near the base of the group, while Liriodendron, Juglans and Aralia seem 
to be more common in the upper part. These observations, however, may be 
simply coincidents; and no particular importance need be attached to them. 
That a determination of phylogeny of species, if not of genera, in the Dakota 
group is desirable goes without saying; and the writer confesses to a hope that 
57. Flora of the Dakota Group, U.S. Geol. Surv., Mon. No. XVII, pp. 20-22. 
