398 OLDER MESOZOIC FLORAS OF UNITED STATES. 
is clear, and a good general idea of the nature of the latter can be 
gained from this view. The irregular attachment of the armor to the 
axis is also well shown. Pl. XCIII, Fig 1, shows this same surface 
as it appeared before it was polished. Fig. 2 gives the outer sur- 
face invested by the ramentum layer, but a few organs are visible, 
having forced their way through it or been disarticulated near its 
outer surface. 
Pls. XCIV and XCV represent two areas of the polished upper 
transverse plane enlarged 4 diameters. An inspection of Pl. XCII, 
Fig. 2, shows that there is a short interval near the center of the speci- 
men over which, for some reason, there is no outer layer, to the left 
of which it extends entirely to the margin, and on the right of which 
it fills a deep depression in the surface. Pl. KCIV includes the 
greater part of the portion on the left where this layer is present, and 
PL. XCV covers the area on the right. All the characters, generic 
and specific, are admirably brought out in these two enlarged areas, 
especially the nature of the ramentum outside of the armor, and its 
wavy, crinkled character as determined by the irregularities of the 
surface and the unknown agencies that compressed it from without and 
packed it down against the trunk. In several places portions of leaf 
bases and perhaps of reproductive organs, detached from the armor 
and caught, as it were, in the meshes of chaff, can be seen lodged in the 
outer coat. These show their normal vascular structure under the 
compound microscope. Owing to inequalities of pressure and unex- 
plained conditions, the long strands of matted chaff are differentiated 
into bands of different color and density that lie parallel to one another 
and: zigzag across the exposed cross sections of the investing layer. 
Near the left margin of Pl. XCV there is a region where one of the 
petioles is clearly seen to cross the boundary line between the armor 
and the ramentaceous covering, and the chaff that developed from its 
left side can also be traced across this boundary and out into the outer 
layer. This is particularly instructive from the point of view of the 
origin of the latter. Upon the whole, these several illustrations afford 
a tolerably clear idea of the character of this remarkable group of 
extinct plants. 
CYCADELLA COMPRESSA Ward. 
Pl. XCVI; Pl. XCVIL 
1900. Cycadella compressa Ward: Proc. Wash. Acad. Sci., Vol. I, p. 269. 
Trunks small (10 to 20 em. high, with major diameter 12 to 15 cm.), 
originally conical, all much compressed laterally or sometimes verti- 
cally or obliquely, unbranched; rock soft, light colored, of low 
specific gravity; organs of the armor tightly appressed to the trunk 
for the most part upwardly, obscuring their arrangement; leaf scars 
