IGNEOUS ROCKS OF THE SIERRA NEVADA. 395 
road south of the Oroville Table mountain, near the Banner gold 
quartz mine. Professor Ward examined these plant remains and 
expressed the opinion that they are of middle Mesozoic age, and 
then referred them to Professor Fontaine, whose report is here- 
with appended : 
[Extract from letter of Professor Wm. M. Fontaine to Professor Lester F. Ward, 
dated April 22, 1895.| 
I have examined carefuily the plants from near Oroville, Cal., collected 
by Stanton and Oliver, with the following results : 
I. Perhaps the most common form is a 7enzopteris, which I cannot dis- 
tinguish from 7. stezoneura, Schenk, found in the Grenzschichten and in the 
lower Rhetic of France. 
2. Not uncommon is a narrow form which is most probably 7eniopteris 
tenuinervis of the same beds, and which is still more characteristic of the 
Rhetic. 
These narrow Tzeniopteris forms are the most abundant imprints among 
the California fossils. This type goes up, it is true, as far as the Oolite, but 
in species not seen among these fossils. Macrotzeniopteris, if present, must 
be much rarer than Tzeniopteris. I am not sure that any of this type is pres- 
ent. There is one large fragment, poorly preserved, that looks much like a 
Macroteniopteris, which resembles 7. magnizfolia. There isa ribbed imprint, 
an imprint of the inner wall of either an Equisetum or Schizoneura. It looks 
more like the imprint Schenk calls Ca/amztes Gumbeli of the Grensch, which 
Schimper makes Eguisetum Gumbelt. There isa very fine plant of Ctenophyt- 
lum grandifolium of the Richmond coal field, and several fragments of the 
same plant. This is of great value in fixing the age of the strata, as this type 
of plant is unmistakable, and is not known except in the uppermost Trias and 
Rhetic. Schenk’s Pterophyllum carnallianum is probably a small variety of 
it. I may say here that a few years ago some Mexican brought a few fossil 
plants from Mexico, and they were submitted to me. Among them were fine 
specimens of this Ctenophyllum, and from them I felt sure that uppermost 
Trias and Rhetic extend into Mexico. 
There are several good imprints of a Podozamites which I cannot distin- 
guish from P. Emmonsi of the N.C. uppermost Trias. Possibly it may be P. 
lanceolatus. If so, it is the Rhetic rather than the Jurassic type of this widely 
extended and persistent form of Podozamites. It is nuw so much expanded 
by species-makers that it is rather a group-type than a species, like Pecopteris 
Whitbiensts. 
There are a number of scattered leaves like Schenk's Zamztes angustifolius 
or more probably Podozamites tenuistrictus of the Richmond coal. 
There is an imperfectly preserved imprint of a very large Danzopsis, 
