60 THE FLORA OF THE AMBOY CLAYS. 
and out of this large number I have endeavored to select such as most 
fairly represent the prevailing characters. It will be seen that they differ 
very considerably in form, some being linear, some lanceolate, and others 
spatulate or long ovate. Sometimes, though rarely, the margins are entire; 
more generally they are undulate, and sometimes acutely toothed. So in 
their nervation they are variable, sometimes a midrib traversing the entire 
length of the leaf, while in other cases it vanishes about the middle. A few 
branches have been found with the leaves still attached. These show that 
the twigs were terminated by three leaves or leaflets springing from a com- 
mon base, while below this there may be one or several pairs placed 
opposite. 
The principal interest connected with this plant is its occurrence in 
Greenland and New Jersey, and it has a value, therefore, quite independent 
of its botanical relations. Whether it should be referred to the genus 
Thinnfeldia is doubtful, and even if it should belong there its botanical 
relations would not yet be ascertained. The genus was described by 
Ettingshausen, who considered it as nearly related to Phyllocladus, while 
Schenk considers it a cyead, and Schimper and Saporta regard it as a fern. 
No fruit or flowers have been found in connection with the Amboy leaves, 
but the aspect which they present is not quite that of any known ferns. 
The nervation is fine, regular, parallel, the side branches diverging from 
the midrib and generally running straight to the margins, but sometimes, 
as in fig. 16, passing to the upper end. 
BaleRA INCURVATA Heer’. 
Pl. X, fig. 6. 
Baiera incurvata Heer, Fl. Foss. Arct., Vol. VI, Abth. II, p. 45, Pl. XTII, fig. 6. 
In his Flora Fossilis Arctica (loc. cit.) Professor Heer describes and 
illustrates a species of Baiera with which we might readily identify the 
plant now figured, except that the curvature of the summit of the frond is 
not distinetly marked in that. This, however, seems to me more likely to 
be an accidental character, the result of violence, as among all the species 
of Baiera no other exhibits a tendency to such a flexure of the frond. As 
