818 OLDER MESOZOIC FLORAS OF UNITED STATES. 
in the Triassic strata of Los Bronces, Sonora, where it occurs in company with 
Pecopteris Stuttgardiensis, Tseniopteris magnifolia, and other well-known Triassic plants 
of Virginia, North Carolina, and Europe. We have, therefore, in these plants evi- 
dence of the Triassic age of all the variegated gypsiferous rocks of Northern New 
Mexico; for the Lower Cretaceous sandstones immediately overlie the plant bed of 
the Cobre. 
In this report Dr. Newberry mentions (p. 69) and figures (pl. v, figs. 
4, 5; pl. vi, fig. 9) some twigs and cones of a plant that he doubtfully 
refers to the genus Pachyphyllum, without assigning any specific name. 
For more convenient reference I will supply a specific name here, and 
as the genus Pachyphyllum is preoccupied and all the species are being 
referred to Heer’s substitute, Pagiophyllum, I will call the plant 
Pagiophyllum Newberry?, assuming that the specimens all belonged to 
one species, although they may have represented more than one. 
Major Powell, in the Geology of the Uinta Mountains, 1876,’ was 
the first to give a local name to these extensive deposits. He calls 
them the Shinarump formation, and thus describes them: 
The summit of the Shinarump group is a series of gypsiferous sandstones exceed- 
ingly friable. They have often been called marls, and the separation between them 
and the massive vermilion sandstone is never very distinct. The difficulty is much 
greater where the gypsum disappears from the lower beds, as it does in places, where 
they are also found to be more indurated and more or less massive sandstones. The 
conglomerate which is found in the middle of the group is persistent over a very large 
area, and the whole group is characterized throughout the entire province by the 
occurrence of silicified wood in large quantities. Sometimes trunks of trees from 50 
to 100 feet in length are found. The Shinarump conglomerate is usually very hard, 
and weathers in such a manner as to form hog backs or cliffs, and the softer gypsifer- 
ous beds above, when carried away by rains, leave behind fragments of this silicified 
wood, so that the Shinarump conglomerate is often covered with great quantities of 
this material. Shinarump means literally ‘‘Shin-au-av’s rocks.’’ Shin-au-av is one 
of the gods of the Indians of this country, and they believe these tree trunks to have 
been his arrows (pp. 68-69). ; 
As already remarked, the silicified wood, which is found in Arizona 
and New Mexico, has long been the subject of popular admiration, and 
has been mentioned in many periodicals ever since emigration com- 
menced to cross the plains. Some of this petrified wood is very beau- 
tiful, admits of a high polish, and is capable of being worked into a 
variety of useful objects. Two large trunks of this material were 
shipped in 1879 by the War Department to the Smithsonian Institu- 
tion, an account of which will be found in Vol. V (1882) of thé Pro- 
ceedings of the United States National Museum, by Lieuts. J. T. C. 
Hegewald and P. T. Swain.’ 
With regard to these silicified and agatized trunks, the economic 
point of view has been particularly dwelt upon by Mr. George F. 
1 Report on the Geology of the Eastern Portion of the Uinta Mountains and a Region of Country 
Adjacent thereto, by J. W. Powell. U.S. Geog. and Geol. Surv. Rocky Mountain Region. Washington, 
1876, 4.° 
2Information concerning some fossil trees in the United States National Museum, by Lieut. Col. 
P. T. Swain, U.S. A., and Lieut. J. T. C. Hegewald, U.S. A.: Proc. U.S, Nat. Mus., 1882, pp. 1-3. 
