4i'(i :\IESOZOIC FLORAS OF UNITED STATES. 



diato summit, which is mostly flat, with the excoption of a small round 

 depression at the center. The longitudinal fi-acture pass(>s near this 

 depression. This apical portion adheres to one side of the flattened 

 fragment, but is connected with the outer portion shown on the oj^po- 

 site side by a continuation of the iu'mor over the thin edge. Below it 

 all has disappeared and the internal parts are exposed. There is a 

 longitudinal fracture and a horizontal fradui'e at right angles to each 

 othei", so that, seen from the l)road side, it has somewdiat the shape of 

 a quadrantal sector, though longer, and a triangular piece is wanting 

 at the summit. 



The extreme height is thus about 27 cm., but this projects 8 cm. 

 beyond the true physiological apex. The maximum width is 18 cm., 

 but the radial fracture is oidy 15 cm. The thickness, which is mainly 

 at right angles to the leaves, t;)ut is nearly parallel to those of the apical 

 portion, varies from 5 cm. at the lowest part to 13 cm. opposite the 

 terminal portion. The partial circumference formed by the thin edge 

 is 38 cm., while that measured over the broad side is 33 cm. The 

 specimen is of a light-ash color, varying to yellowish within. The sub- 

 stance is fine grained and firm, but of medium specific gravity. (Locality : 

 PI. LXXX, No. 44.) 



PI. LXXXVII, Fig. IV, 12 shows standing on its edge (i. e., lying 

 down), the onter siu'face of the R. T. Donaldson fragment. No. 6, W. (\, 

 B., No. 3341. This fragment came from the side of a medium sized 

 trunk, apparently remote from both base and summit, consisting of 

 the armor and at least one ring of the woody zone. It is convexo- 

 concave, so as to make the cross section crescent-shaped. The inner 

 concavity is exaggerated so as to form a central depression or trough. 

 Nearly the whole inner surface is thus eaten away, the softer much 

 deeper than the harder parts. The effect is to leave projections of the 

 latter and to give the surface a studded appearance. The outer parts 

 are imperfectly preserved, the armoi- being quite absent over the lower 

 fourth of the specimen. It seems also to have suffered somewhat fi'om 

 vertical compression. The fragment is of a uniform light-ash color, 

 rather fine grained, but soft, and apparently somewhat argillaceous. 

 The specific gravity is low. The length (h(nght) preserved in the frag- 

 ment is about 14 cm., the tangential length 23 cm., and the radial thick- 



