DESCRIPTIONS OF SPECIES. 33 



parisons may also be made with Thyrsopteris Murrayana (Brongt.) Heer," T. Maa- 

 Iciana Heer,* T. gracilis Heer*^ and Dicksonia clavipes Hear,'' from the Jurassic of 

 Siberia. 



Comparisons with hving species of the above genera, and with others having 

 similar characters, indicate that our fossils most nearly resemble Onoclea, and this 

 resemblance would seem to justify their reference to the genus, even though we 

 have thus far failed to find any associated sterile fronds which could properly be 

 included in it. 



Locality: Glen Cove, Long Island, PI. I,.figs. 1-4. Figs. 1-3 collected by David 

 White. Specimens in U. S. Nat. Mus. Fig. 4 collected by Arthur Holhck. Speci- 

 men in Mus. New York Bot. Card. 



Little Neck, Northport Harbor, Long Island, PI. I, fig. 5. Collected by Arthur 

 Hollick. Specimen in Mus. New York Bot. Card. 



Gay Head, Marthas Vineyard, PI. I, fig. 6. Collected by David White. 

 Specimen in U. S. Nat. Mus. 



Nashaquitsa, Marthas Vineyard, PI. I, fig. 7. Collected by David White. 

 Specimen in U. S. Nat. Mus. 



Order SALVINIALES. 



Family MARSILEACE/E. 

 Marsilea Andersoni Hollick. 

 PI. I, figs. 14-18. 

 Marsilea Andersoni Hollick, Bull. New York Bot. Gard., vol. 3, 1904, p. 409, pi. 71, figs. 1-3. 



The figures of the specimens upon wliich the original description of this species 

 was based are reproduced on PI. I, figs. 14-16, and figures of leaves of the Hving 

 Mexican species, M. Holtingiana Schaff., introduced for comparison, are shown in 

 figs. 19-21. It may be objected that the fossil specimens appear to be simple pel- 

 tate rather than compound leaves, but it is probable that the pressure to which they 

 were subjected in the process of fossilization resulted in the obliteration of the lines 

 of demarcation between the leaflets, and this probability is strongly emphasized by 

 the appearance of the flattened herbarium specimens, in which the borders of the 

 overlapping leaflets are often difficult to distinguish from the nervation without the 

 aid of a magnifying .glass. 



Figs. 17 and 18 represent poorly preserved specimens, which might not have 

 received any attention except for the comparison made possible by the better 

 preserved ones first discovered. 



Fragmentary remains, apparently of similar appearance to ours, have been 

 described and figured by several authors as ferns or gymnosperms, under various 

 generic names, and one which perhaps merits critical consideration in this connection 



a Fl. Foss. Aret., vol. 4 (Jura-Fl.), p. 30, pi. 1, flgs. 4b, 4e; pi. 2, figs. 1, 4, 4b; pi. 8, fig. lib. 



i Ibid., p. 31, pi. 1, fig. lb: pi. 2, flgs. 5, 5b. 



clbid.,p. 32, pi. 1, fig. 5. 



i Ibid., p. 33, pi. 2, figs. 7, 7b. 



