ARTICLE IV. 
LETTER FROM PROFESSOR J. W. BAILEY, DESCRIBING THE STRUCTURE OF 
THE FOSSIL PLANT FROM POSUNCULA RIVER. 
West Pornt, New York, March 22, 1855. 
DEAR SIR : I send herewith a sketch of the structure of the fossil plant from the boulder in 
the bed of Kern River, west slope of the Sierra Nevada. 
The plants, as far as I can make out the structure, are annual shcots of an exogenous struc- 
ture, presenting a distinct pith, (p. in the drawings, Plate XII, figs. 1 and 2); medullary rays 
(r); a layer of liber (1); and a loose succulent bark (b), having large lacuna (la). In the outer 
portion of the wood a series of large vessels, v 1; of smaller, v 2; and of still smaller ones, v 3, 
are placed. I could not detect upon these vessels any indications of spiral or dot. 
The specimens from the east slope of the Sierra agree in all essential points with the above, 
the only difference noticed being the development of a few large vessels surrounded with woody 
fibre within the pithy portion. ۱ 
I cannot venture, with the limited data furnished above, to form any opinion upon the affini- 
ties of these plants. 
The vertical section, fig. 1, is made up from observations of various splinters from different 
parts of the plants which I encased in Canada balsam. The horizontal section, fig. 2, is from 
the section made by the lapidary in New York, which I afterwards rubbed down to half the 
thickness the lapidary had given. The section thus obtained was as perfect as if from a recent 
plant. It showed the shells filled with transparent silica, and in the larger lacun® the arrange- 
ment of the silica into small sperical agates was distinctly visible. 
Yours, very respectfully, 
J. W. BAILEY. 
W. P. Brake, Esq., Washington, D. C. 
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