DESCRIPTION OP SPECIES. 83 



have belonged to a larger leaf than that depicted in Plate XLIII, Fig. 1. 

 Plate XLV, Fig. 2, gives the dimensions of one of the largest leaflets. In 

 it the lower part of the leaf only is seen, but the length is restored from 

 actually seen and measured lengths on leaves of this size. Plate XLIV, 

 Fig. 2, gives the nervation and granulation somewhat enlarged, and Fig. 2 b 

 represents a portion of the leaf where the dots are elongated by pressure 

 into transverse bars. This portion is still more enlarged. Plate XLIV, 

 Fig. 1, gives the bases and portions of four large leaves and the stem on 

 which they are inserted. One of the leaves is nearly entire. Plate XLIV, 

 Fig. 2 a, gives the mode of consolidation and divergence of one of the 

 nerve-bundles which leave the pedicel to enter the leaflet. It is enlarged 

 to show the appearance as seen under a strong lens. 



It will be seen that this fine plant in some features differs from previ- 

 ously-described species of Sphenozamites. The pedicels are inserted some- 

 what within the margins of the stem, and this has led me to modify the 

 diagnosis of Saporta so that it may read: "Leaflets inserted on or near the 

 margin of the stem." This is justified by what is seen on the plants of this 

 genus which have been previously described and figured. It is clear that 

 the leaflets of S. latifoUus Sap. were not inserted exactly on the side of the 

 stem, but a little within its upper surface. This is also the case with S. 

 Bossii, Zign.,a figure of which is given by Saporta in the "Pal. Francaise 

 Plantes jurass.," plate cxiv, fig. 2, where the bases of some of the leaflets are 

 attached a little within the margin of the upper surface of the stem. The 

 peculiar nervation of S. Rogersianus is not given in any previously described 

 species, but this may arise from the fact that the nervation was not so well 

 shown as in the Richmond plant. 



Dr. Emmons gives a representation of a leaf marked with delicate 

 transverse bars on the veins in plate 6, fig. 5, of his "American Geology," 

 which is, I suppose, the plant he describes on page 35 as Calamites punctatus, 

 although he refers for the figure of this to plate 2, fig. 5. This is clearly 

 the same with the plant now in question, as may be easily seen from the 

 figure. He takes it to be a stem, but sees no articulations on it. 



Dr. Newberry gives a figure on plate viii, fig. 5, of a plant found at 

 Sonora, in his report on the Macomb Expedition. It is the summit of a 



