448 MESOZOIC FLORAS OF UNITED STATES. 



taken through the axis, but on account of eccentricity it is 33 cm. where 

 greatest. The shorter diameter is 20 cm. The greatest vertical measure- 

 ment obtainable is 13 cm., but the general vertical thickness is about 

 11 cm. It is impossible to say how much the missing portion would 

 have added to these measurements. The shape is extremely irregular, 

 and what is to all appearances the true summit containing a perfect 

 terminal bud has an axis which is nearly at right angles to the axis 

 indicated by the medulla. The specimen is of a reddish-brown color, 

 lighter than the average. The terminal bud is 6 cm. high, definitelj^ 

 bounded at its base, which is 65 mm. in diameter and regularly convex 

 downward, so that if removed a perfect "crow's nest" would remain. 

 The terminal bud seems to consist of a mass of densely matted bracts 

 imbricated over one another along a central axis, i. e., growing shorter 

 and shorter from without inward. The specimen has been cut through 

 the center of the axis of the terminal bud, the section passing through 

 the armor and general axis, thus exposing the internal structure. The 

 cut faces have been polished and a photograph made. From this cut 

 face the thickness of the armor is seen to be about 4 cm. The leaf scars 

 are much compressed and pass down through the armor in the form of 

 fine lines. The armor rests upon a loose heterogeneous layer 15 mm. 

 thick. This layer does not occur beneath the terminal bud, which rests 

 on a triangular mass of fine homogeneous tissue 35 mm. thick and extend- 

 ing to the medulla, which is much flattened, about 32 mm. thick, and 

 porous. (Localit}^: PL LXXX, near No. 68.) 



PI. XCVII, Fig. 1 represents the Noah Donaldson trunk, W. C, B., 

 No. 1470. It is a portion of the medulla of a large, much laterally com- 

 pressed trunk with a small piece of the external part attached to the 

 narrow edge. The medulla itself is decayed in the middle and irregularl}^ 

 broken or eroded away above and below with an opening on one side. 

 The whole is very light colored, porous, and sandy, but rather firm. The 

 total length is 31 cm. and the maximum width 18 cm. The thickness 

 is 9 cm. 



The armor is about 2 cm. thick, and no definite line can be drawn 

 between it and the mass of fibers that mostl_y makes up the woody cylinder 

 which it incloses, and which is also about 2 cm. thick. This latter so 

 clasps one of the edges of the pith for a length of 21 cm. as to leave it 



