THE MARYLAND CYCADS. 421 



My theory of its origin is that the trunk lay for a long period on its side in just 

 such a way that this plane would be horizontal; that wliile so lying it was buried 

 in a deposit of the sand, gravel, and pebbles described; and that it so happened 

 that one of the well-known seams of iron incrustation was formed at that level and 

 to that thickness. This penetrated the openings in the stone and probably adhered 

 to it, forming a wmg all round it until some agency wore it off to the level of the 

 general surface of the specimen. (Locality: PI. LXXX, No. 97.) 



PI. LXXXII represents the most perfect side of Johns Hopkins 

 University Cycad No. 2, and is a reproduction of the photograph made 

 by Mr. Tyson and sent by him to Sir WiUiam Dawson, of which a full 

 account is given in the historical part of this paper (pp. 409-416). 

 This is a fine trunk, with one side complete from base to summit. It is 

 considerably compressed laterally. The base is broken across obliquely 

 in the direction of the major axis, but so as to leave one-half intact. On 

 the same side that is broken at the base there is a large cavity eroded out 

 of the summit, as shown in Professor Fontaine's pi. clxxvi. The summit 

 itself is occupied by a normal depression or crow's nest, with a terminal 

 bud in the center much lower than the surrounding rim. The eroded 

 cavity is at one side of the terminal bud. I do not think that it repre- 

 sents another bud or axis of growth, as suggested by Professor Fontaine. 

 The specimen is of a rather hght-reddish color, well silicified, but not 

 hard or heavy. It stands 35 cm. high. The major axis of a cross section 

 just above the base where thickest is 35 cm. and the minor axis 24 cm. 

 The latter rapidly diminishes upward to 15 cm. at the summit (see 

 Professor Fontaine's pi. clxxv), but the major axis decreases much less 

 to near the summit, where it rounds off abruptly, as shown in pi. clxxiv 

 and pi. clxxvi. The maximum girth is 85 cm., but this is above the 

 middle, below which point the basal fracture prevents measurement. It 

 was probabl}^ nearly 1 meter near the base. The specimen is remarkable 

 for the number and conspicuousness of the floral axes. Some of these 

 are 3 cm. or 4 cm. in diameter. Sometimes the center is gone, but in 

 most cases it is present and either solid or pitted all over with the scars 

 of the involucral or seminal organs arranged concentrically. A number 

 of these large axes protrude in a marked manner, and one which occurs 

 at the margin of the fracture resembles Bennettites Morierei. Professor 

 Fontaine fancied he detected two classes of these organs, but I am unable 

 to see any generic difference in the lateral flower buds. Some protrude 



