54 
Angiospermophyta 
Genus, sapindopsis Fontaine 
Sapindopsis brevifolia Fontaine (?) 
Plate VIII, figures 8, 9 
Sapindopsis brevifolia Fontaine, U.S. Geol. Surv., Mon. 15, p. 300, PL 153, 
fig. 4; PI. 155, figs. 1, 7; Pl. 163, fig. 3 (1890) ; in Ward, Idem., 48, 
pp. 481, 482, 528 (1906). 
Berry, U.S. Nat. Mus., Proc., vol. 38, p. 644 (1911); Lower Cre- 
taceous, Md. Geol. Surv., p. 473, PL 87, figs. 2-5 (1911); U.S. 
Geol. Surv., Prof. Paper 129, p. 216, Pl. 55, fig, 1; PL 59, fig. 1 
(1922). 
Leaves odd pinnate, the terminal leaflet considerably larger than the 
lateral leaflets, of which only two pairs are known. These are opposite. 
Leaflets generally somewhat crowded so that their margins often overlap, 
with sub-acute tips and cuneate bases, varying in length from 2 to 5 cms., 
and in width from 0*7 to 1*6 cms., averaging about 3 cms. long and 1*3 
cms. wide. Often inequilateral toward the base and showing considerable 
variation in decurrence — in some the rachis is conspicuously winged, in 
others the leaflets are all petiolulate. Midribs stout. Secondaries rather 
straightly ascending, camptodrome, usually seen with difficulty, as they 
are relatively slender and the leaf texture is coriaceous. 
The foregoing description is drawn up from the complete material 
found in the Patapsco formation and the Cheyenne sandstone. That from 
the Lower Blairmore is sparse and incomplete and the identification is 
consequently queried, since this material fails to definitely show the pinnate 
habit, although this is indicated by the position of the leaflets in one 
specimen, and the leaflets agree closely with those of this species. 
The species, compared with the other species of this genus, is rather 
poorly marked and appears to represent a variant of Sapindopsis variabilis 
with which it is generally associated, although this is not the case in the 
Lower Blairmore. It is the only dicotyledon definitely recognized in the 
Lower Blairmore and is of considerable significance in determining the age 
of that horizon. It does not occur in the Upper Blairmore although the 
allied Sapindopsis magnifolia is found at that horizon. 
Sapindopsis brevifolia was originally described from material from 
the Patapsco formation, the uppermost member of the Potomac Group in 
Maryland and Virginia. It is also present in the Cheyenne sandstone of 
southern Kansas. The first horizon is late Lower, and the second early 
Upper, Cretaceous in age, that is Albian and Cenomanian in terms of 
European Cretaceous chronology. 
The Lower Blairmore occurrences include the original and counter- 
part of a single fragment from locality DB1, a single leaflet and the original 
and counterpart of two partly superimposed leaflets from locality DF1. 
