JUNE 7, 1901.] 
record, especially with respect to the earlier 
periods, and the uncertainty which exists rela- 
tive to precise limitations as defined by the 
vegetation, lead the author to treat the Amer- 
ican Trias asa geographical unit, between which 
and any of the recognized Huropean series it 
has as yet been impossible to establish exact 
correlation, but it is worthy of remark that not 
only are the plants of the European Trias most 
numerous in the uppermost number of the series, 
7. é., in the transition beds or the Rhetic, but 
that all the fossil plants of the American Trias 
have their nearest affinities in Europe, with 
those of the latter formation. 
The principal plant-bearing deposits of the 
American Trias are to be found in the Connec- 
ticut Valley, near Richmond, Virginia, and in 
North Carolina. They are also extensive in 
New Mexico and Arizona, extending into Utah, 
Neyada and Colorado, and probably also into 
the Indian Territory and Texas. They also 
appear in California in the well-known beds at 
Oroville. The Pennsylvania area was very 
carefully studied by Mr. Wanner, whose ma- 
terial was revised by Professor Fontaine, and 
for a total of thirty-one species shows Filices 
10, Equisetaceze 1, Cycadaceze 10, Bennettitaceze 
1, Ginkgoales 1, Coniferee 7 and Monocotyle- 
dons (?) 1. 
In the Virginia area the work of Professor 
Fontaine led Dr. Stur, of the Austrian Geologi- 
cal Survey, to identify many of the species with 
plants from the European Keuper, whence he 
concludes that the Trias of Virginia and that of 
Lunz are of the same age. 
The most complete and noteworthy collection 
of plants from the older Mesozoic is that of 
Dr. Emmons from North Carolina, deposited in 
the museum of Williams College, where they 
were subsequently studied by Professor Fon- 
taine with the result that it was found to con- 
tain Filices 10, Hquisetacese 2, Cycadacez 14, 
Bennettitaceze 1, Ginkgoales 1, Coniferze 6 and 
of doubtful affinity 4, in a total of thirty-eight 
forms. Comparing this list with that obtained 
from Pennsylvania, a remarkable correspond- 
ence between the representatives of the differ- 
ent familes is here noted. 
One of the most notable features of the 
southwestern area is to be found in the very 
SCIENCE 
905 
abundant remains of trees which haye become 
silicified and form the well-known ‘ Petrified 
Forest of Arizona.’ These remarkably well 
preserved remains have already been fully 
described in a special memoir by Professor 
Ward, and they are now dealt with only so far 
as is necessary to connect them with the special 
subject under discussion. The wood has been 
identified by Knowlton as that of Arancorioxylen 
Arizonicum. 
The Jurassic flora embraces a description of 
fifty-twvo species, of which three only are re- 
corded for the first time. About half of these 
species are embraced in the Oroville flora of 
California and include Filices 13, Cycadaceze 10, 
Ginkgoales 1, Coniferee 3 and unknown 1; 
while the remaining twenty-four from the 
Jurassic of Wyoming represent Cycadacez 22, 
Coniferee 2. 
Of the 28 species in the Oroville flora, only 12 
are to be regarded as of definite value in the 
determination of geological age. Of these Clad- 
ophlebis spectabilis, C. arguluta, C. whitbiensis 
tenuis var. a; Thyrsopteris Maakiana, Podozamites 
lanceolatus, P. lanceolatus latifolius and Pinus 
Nordenskioldi were determined by Heer to be 
characteristic of the Jurassic in a horizon equiy- 
alent to the Lower Oolite of Scarborough, 
whence it becomes of special interest to observe 
that Seward * refers to the occurrence of Clad- 
ophlebis whitbiensis, Thyrsopteris Maakiana and 
Podozamites lanceolatus. Cladophlebis whitbiensis 
he now recognizes as properly identical with 
Todites Williamsoni of Brongniart, a species of 
wide distribution in the Jurassic of Europe, 
Greenland and Siberia and characteristic of the 
Yorkshire Oolite. Thyrsopteris Maakiana he 
identifies with Coniopteris hymenophylloides, which 
occurs in the Jurassic of Siberia and also consti- 
tutes one of the most characteristic species in 
the Oolite of the Yorkshire Coast. Podozamites 
lanceolatus has an exceptionally world-wide dis- 
tribution, and is especially characteristic of the 
Jurassic strata. The Pagiophyllum type of con- 
ifer which is highly characteristic of the Jurassic, 
is represented in the Oroville series by P. Wil- 
liamsoni as the only conifer of importance ; 
while in Europe and China, as also in the 
* «Catalogue of Mesozoic Plants,’ British Museum, 
1900. 
