REPORT ON FOSSIL PLANTS.
BY LESTER F. WARD.
DEPARTMENT OF THE INTERIOR,
UNITED STATES GEOLOGICAL SURVEY,
Washington, D. C., March 12, 1891.
Mr. I. C. RUSSELL, United States Geological Survey.
MY DEAR SIR: The following report upon the small collection of fossil plants made by you at Pinnacle pass, near Mount St. Elias, Alaska, and sent to this division for identification has been prepared by Professor F. H. Knowlton, who gave the collection a careful study during my absence in Florida. Previous to going away I had somewhat hastily examined the specimens and seen that they consisted chiefly of the genus Salix, some of them reminding me strongly of living species. I have no doubt that Professor Knowlton's more thorough comparisons can be relied upon with as much confidence as the nature of the collection will permit, and I also agree with his conclusions.
"The collection consists of seven small hand specimens, upon which are impressed no less than seventeen more or less completely preserved dicotyledonous leaves.
"These specimens at first sight seem to represent six or eight species, but after a careful study I think I am safe in reducing the number to four, as several of the impressions have been nearly obliterated by prolonged exposure and cannot be studied with much satisfaction.
"The four determinable species belong, without much doubt, to the genus Salix. Number 1, of which there is but a single specimen, I have identified with Salix californica, Lesquereux, from the auriferous gravel deposits of the Sierra Nevada in California.38 The finer nervation of the specimens from the auriferous gravels is not clearly shown in Lesquereux's figures, nor is it well preserved in the Mount St. Elias specimens; but the size, outline, and primary nervation are identical.
"Number 2, of which there are six or eight specimens, may be compared with Salix raeana, Heer,39 a species that was first described from Greenland and was later detected by Lesquereux in a collection from Cooks inlet, Alaska.40 The Mount St. Elias specimens are not very much like the original figures of Heer, but are very similar, in outline at least, to this species as figured by Lesquereux.41 They are also very similar to some forms of the living S. rostrata, Richardson, with entire leaves. It is clearly a willow, but closer identification must remain for more complete material.
"Number 3, represented by four or five specimens, is broadly elliptical in outline, and is also clearly a Salix. It is unlike any fossil form with which I am familiar, but is very similar to the living S. nigricans, For., var. rotundifolia, and to certain forms of S. silesiaca, Willd. The nervation is very distinctly preserved, and has all the characters of a willow leaf.
"Number 4, represented by three or four very fine specimens, is a very large leaf, measuring 13 cm. in length and 3½ cm. in width at the broadest point. It may be compared with Salix macrophylla, Heer,42 but it cannot be this species. It is also like some of the living forms of S. nigra, Marsh., from which it differs in having perfectly entire margins.
"While it is manifestly impossible, on the basis of the above identifications, to speak with confidence as to the age or formation containing these leaves, it can hardly be older than the Miocene, and from its strong resemblance to the present existing flora of Alaska it is likely to be much younger." [F. H. Knowlton.]
Very sincerely yours, LESTER F. WARD.
38 Mem. Mus. Comp. Zool., vol. VI, no. 2, 1878, p. 10, pl. i, figs. 18–21.
39 Flor. foss. Arct., vol. I, 1868, p. 102, pl. iv, figs. 11–13; pl. xlvii, fig. 11.
40 Proc. Nat. Mus., vol. V, 1882, p. 447.
41 loc. cit., pl. viii, fig. 6.
32 Tert. Fl. Helv., vol. II, 1856, p. 29, pl. lxvii, fig. 4.