22 T. G. HALLE, MESOZOIC DEPOSITS AND FLORAS OF PATAGONIA AND TIERRA DEL FUEGO. 
folia NATH. The only difference, except the smaller number of loculi, is that there 
is no trace of the fine concentric lines which mark the surface of the synangium of 
the Greenland species (NATHORST, l. c., pl. 3, figs. 66, 68, 69). This feature also 
may have been present but, as has been remarked above, the roof of the synangium 
is not preserved in the Patagonian specimens. 
The spores (pl. 1, figs. 8, 9) are tetrahedral to rounded with triradiate mark- 
ings; they show no trace of any other surface-sculpture. "They measure about 25—30 p 
in diameter. 
The specimens of Nathorstia latifolia on which Prof. NATHORST worked out the 
structure of the sori, did not show the venation well enough to permit of a definite 
decision whether it was reticulate or not. But Prof. NATHORST points out that 
Drynaria fascia BAYER (1900) from the Cenomanian of Bohemia is possibly identical 
with the Greenland species, in which case Nathorstia also should be characterized by 
anastomosing veins. An examination of the Bohemian specimens having failed, however, 
to prove the synangial nature of its sori, the question of identity must remain open. 
The Patagonian fossil is too different from the species of Nathorstia hitherto 
described to be identified with any of them. All the known species have the pin- 
nules retreciated at the base and attached to the rachis in one point only. The 
broad decurrent bases of the pinnae and the winged rachis form a quite sufficient 
distinction of Nathorstia alata. Tt is of importance to note that the genus, as far as 
it is hitherto known, is confined to the Lower and Middle Cretaceous. 
Nathorstia alata was found only in the locality c, near Rio Fösiles. 
Gleichenites San-Martini n. sp. 
PIE fos LATE 
The specimens figured in pl. 1, fig. 14, can with fairly great certainty be re- 
ferred to the genus Gleichenites GOEPPERT; but it is not possible to identify them 
with any particular species. As they, though small, are well preserved, they may 
accordingly be described as a new species, Gleichenites San-Martini. 
Pinnae linear, very long and slender. Pinnules densely set but not somfldert 
attached by the whole of their bases, at a wide angle, often quite perpendicular to 
the pinna-rachis. Shape of the pinnules semicircular or very shortly ovate, with 
broad rounded apex. Venation consisting of a slender midrib and few, 2-—4, simple 
secondary veins on each side. Sori single, one in each pinnule, a little forward of 
the midrib. 
It is not known whether the frond of this species was dichotomously branching 
or not, only one small fragment with the pinnae still attached to the rachis existing 
in the collection. In this fragment, the pinnae are alternately placed and perfectly 
perpendicular to the rachis. It may be, however, that these characters are not con- 
stant. The most important characters are the shape of the pinnules and the position 
of the sori. The pinnules are always short — in the pinnae to the left in pl. 1, 
