Locality
From Hollick (1930) (p. 56-57)
"Yukon River, north bank, immediately above Pickart's mine (original No. 3AH15b); collected by Arthur Hollick and Sidney Paige in 1903 (lot 3255) (pl. 20, figs. la, 2, 3, 6, 7). Yukon River, north bank, about 16 miles above Kaltag (original No. 3AH25); collected by Arthur Hollick and Sidney Paige in 1903 (lot 3264) (pl. 20, figs. 4a, 5)."
Description
From Hollick (1930) (p. 56-57)
"Plate 20, Figures la, 2-4a, 5-7"
"Sequoia ambigua Heer, Die Kreide-Flora der arctischen Zone: Flora fossilis arctica, vol. 3, No.2, p. 78, pl. 21, figs. 1, 2a, 3-9, l0a, b, c; pl. 25, fig. 5, 1874." (Heer 1874)
Remarks
From Hollick (1930) (p. 56-57)
"There can be no question in regard to the identity of our specimens with Heer's species from the Kome beds of Greenland; and the same may be said in regard to specimens from the Magothy formation of Marthas Vineyard, Mass., collected by White (1890) (p. 97, pl. 2, figs. 2, 3). The identity of most, if not all, of the diverse forms from the Cretaceous of the eastern United States that have been referred to the species, however, is exceedingly doubtful, as may be appreciated by an examination and comparison of the figures by Fontaine (1889) (pp. 245, 246, pl. 188, figs. 2, 2a; pl. 120, figs 1 - 2a, 3 - 6a; pl. 127, figs. 5, 5a; pl. 132, figs. 3, 3a) of specimens from the lower part of the Potomac group of Maryland, in regard to which he says : "There are a few points of difference in the Kome and Potomac forms. * * * The leaves of the Potomac plant are apparently not quite so thick as those from Kome and not so constantly incurved, and they are usually more closely placed."
Subsequently Berry (1911; 1919) (p. 449, pl. 78, figs. 1 - 7; p. 66, pl. 6, figs. 3, 4) still further enlarged the scope of the species by including in it the three species Sphenolepidium recurvifolium Fontaine, Sphenolepidium dentifolium Fontaine, and Athrotaxopsis expansa Fontaine, all of which may be specifically identical with the Potomac so-called Sequoia ambigua but hardly with the species as defined and figured by Heer.
Fontaine (1905) (p. 264, pl. 69, fig. 6) has also reported it from the Shasta series of California upon the basis of a twig of very doubtful identity, In fact, so far as satisfactory identification of the species is concerned, its distribution in America, outside of Alaska, appears to be restricted to the Lower Cretaceous of Greenland and the basal Upper Cretaceous of the eastern United States; although it is also recorded from the Kootenai formation (Lower Cretaceous) of Montana by Knowlton (1907) (p. 126) and the Neocomian of Mexico by Nathorst (1893) (p. 51, figs. 1 - 3); but I have not seen the specimens upon which either of these records was based."