934 OLDER MESOZOIC FLORAS OF UNITED STATES. 
any fossils from the Trias in this region, with a single exception. — 
That exception relates to Lecrone’s copper mine. About twenty 
years ago fossil teeth and bones were found at the bottom of a shaft 
sunk for the purpose of developing a supposed vein of copper. These 
were sent to the late Prof. E. D. Cope, of Philadelphia. 
The drawings were all carefully made by the writer and are 
intended to be exact illustrations of the specimens. No details have 
been supplied, though the possession of a number of other specimens 
in different instances clearly furnished the material from which to fill 
out missing parts. 
In the description of fossil plants the publications of William M. 
Fontaine have been referred to almost exclusively. Such has been the 
case not simply because the York County fossil plants are almost 
wholly included in Fontaine’s Mesozoic Flora, but because of the com- 
pleteness and clearness of his descriptions and illustrations. 
The writer is indebted to Mr. J. Heckert for valuable assistance. 
In this connection it is but just to acknowledge the potent influence 
exerted by the indefatigable energy and comprehensive and exhaust- 
ive methods of research of the Director of the United States Geological 
Survey, Hon. Charles D. Walcott, whom it was the author’s privilege 
to accompany in a hurried inspection of the Cambrian rocks of this 
section. That association served as an inspiration and stimulated the 
writer to still more zealously continue his researches. 
The author is furthe1 indebted to the Director of the United States 
Geological Survey and to Prof. Lester F. Ward and his associates in the 
National Museum for the opportunity of examining the collection of 
Mesozoic and related floras at Washington. 
Flora.—A brief description of the geological and lithological fea- 
tures of the Trias in this section will be found in the reports of the 
Geological Survey of Pennsylvania. 
In York County the bedded Triassic series is largely made up of 
the characteristic red shales, quartz conglomerate, and sandstones, 
matrices not favorable to the preservation of recognizable fossil forms. 
Moreover, intrusive trap, in dikes and great sheets, has contributed 
greatly to modify and disturb the original deposits. Because of these 
conditions the search after impressions that can be identified is gen- 
erally disappointing and unproductive. A few localities yield illegi- 
ble impressions of plants. Occasionally there is but a dark, earthy, 
carbonaceous band, in a sand bank, or a thin, short seam of coal, a mere 
trace of irregular width, unmistakably to locate a vegetable deposit. 
‘ More frequently rough casts of limbs or trunks of trees, in blocks 
of quartz conglomerate or sandstone of varying composition, mark 
the final resting place of vegetation now decomposed. 
A shale at the York Haven locality, yielding most of the plants 
