— 443 — 
bably near that of the specimen shown in Fig. 11, or not far from the 
Iraty black shale. 
Locality: Bofote, Sdéo Paulo. Horizon about 155 meters above the 
Iraty black shale. 
Lepidondendron 
Sternberg, Fl. d. Vorwelt, vol. I, fasc. 1, 1820, p. 25. 
The genns Lepidodendron includesa group of arborescent Lepido- 
phytes whose nearest relatives in the flora of today are found in the 
Lycopodiacece. The trees, which sometimes attained great size, are 
dichotomous in equal or unequal divisions, the branchlets being stout 
and rigid in some species and gracefully slender and drooping in 
others. The greater part of the thickness of the trunck is comprised 
of the very thick cortex which is somewhat complicated in stru- 
cture. The inner axis consists of a cylinder of primary or centripe- 
tal wood, with or without a parenchymatous pith. In most of the 
species there is developed, external to the primary wood, at some 
stage in the growth of the tree, a cylinder of secondary, exoge- 
nous wood consisting of spiral and reticulate vessels succeeded by 
scalariform tracheides, somewhat irregularly parted by medullary 
rays. The bark is divided into an inner and an outer cortex, em-~ 
bracing a periderm which marks another line of exogenous deve- 
lopment. 
In most flattened and carbonized remains of Lepidodendron the 
cortices, especially the outer cortex, constitute jthe chief residual 
matter, and it is this which usually forms the thin carbonaceous 
sheath enveloping the sandstone casts of uprigth trunks. 
The essential features by which the genus and species of Lepi- 
dodendron are recognized are those of the rhomboidal leaf cushions 
which support the leaves or leaf scars. These leaf cushion are rho- 
mboidal and more or less elogaled in the longitudinal sense so as some- 
times to become fusiform. They are usually prominent, sometimes 
projecting slightly upward, and are either marked by a longitudinal 
crest which is interrupted by the leaf scar, or they are somewhat stron- 
gly convex and frequently transversely wrinkled. ‘The leaf scar is 
placed near the middle, or in the upper half of the leaf cushions and is 
tranversely rhomboidal, with acute lateral angles. It is marked, at or 
above the level of its greatest horizontal diameter, by three, usually 
