220 OLDER MESOZOIC FLORAS OF UNITED STATES. 
like Lepidodendron, but evan if it be such the absence of all other Paleozoic plants 
and the fact that the accompanying flora is wholly Mesozoic would simply indicate 
that Lepidodendron survives into the Mesozoic. It is noteworthy, with reference to 
what Lesquereux says, that this Richmond coal-field plant is more like L. Veltheimi- 
anum than any other of that genus. Ido not know what Mr. Lyman’s authority is 
for the statement that the Newark beds are 9,000 feet below the Milford strata, or for 
the great thickness he gives for the Pennsylvania Trias, 27,000 feet. I have not seen 
any publication indicating that thickness. Do you know of such? Mr. Lyman 
questions my rejection of Lepidodendron from the Mesozoic flora. I do not see that 
that, if correct, helps his contention, which is that the fossils may be Lepidodendron, 
and therefore the beds may be Paleozoic. If we grant that these plants are Lepi- 
dodendron, all that’can be deduced is that this genus lived in the Mesozoic, for the 
supposed Lepidodendron of North Carolina and Virginia is accompanied by an 
abundance of well-marked Mesozoic plants; otherwise we must conclude that the 
North Carolina and Virginia bedsare Paleozoic. Surely he would not maintain that. 1 
In all this the question has not been whether we have in these few 
doubtful remains representatives of the flora of the lowest Triassic 
beds corresponding to the Variegated Sandstone or Vosgian and the 
Muschelkalk, but whether they are Mesozoic or Paleozoic. Professor 
Fontaine seems to have sufficiently answered this question, and all 
agree to the absence thus far of the characteristic Lower Triassic 
forms, such as Athophyllum, Voltzia, Albertia, and Yuccites. 
With regard to the alleged Trias of Prince Edward Island,’ it pre- 
sents a question singularly similar to the one just considered, since 
none of the fossil plants at least are claimed to represent the Lower 
Trias, while two of them are decidedly Paleozoic in their affinities. 
I therefore fully indorse all that Dr. Knowlton has said® with regard 
to them. JI had myself raised the question whether the Cycadeoidea 
abequidensis may not represent a cone of some coniferous tree. It is 
very small for a cycadean trunk, though this alone would not negative 
such a reference. Sir William Dawson’s fig. 29, which is about 
natural size, does not bring out cycadean characters, and the supposed 
scars of leaves and buds represented enlarged in figs. 29a and 290 do not 
help support his view. He does not explain why he places the small 
end down and describes it as ‘‘ obovate” instead of reversing it and 
treating it as originally conical, but if the side of the scars toward the 
small end are, as represented, more pronounced than that toward the 
large end, this would seem to justify that position. A photograph, 
slightly enlarged, which Sir William was so good as to send me, and 
which bears enlargement with a lens much better than the engraving, 
still fails to answer the question of orientation, but it must be admitted 
1At the time this letter was written the negotiations described below (pp. 274-276) relative to the 
then recently discovered Emmons’s collection were going on, and it will be observed that Professor 
Fontaine, after examining the specimens themselves, refers the supposed Lepidodendron to Zamios- 
trobus virginiensis, virtually confirming his previous conclusion derived from an examination of the 
figures alone. 
2Report on the Geological Structure and Mineral Resources of Prince Edward Island, by J. W. 
Dawson, assisted by B. J. Harrington; Montreal, 1871; 51 pp., 3 plates. See pp. 13-22, 45, 46, pl. iii. 
3In the Newark system, by I. C. Russell: Bull. U. 8. Geol. Survey No. 85, 1892, p. 29. 
