494 FOSSIL CYCADE^E IN DORSETSHIRE. 
of graceful foliage surrounding the summit of a 
simple cylindrical trunk, it resembles a Palm. 
The trunk in the genus Cycas, is usually long. 
That of C. circinalis rises to 30 feet.^ In the 
genus Zamia it is commonly short. 
Our figure of a Zamia pungens,t (PI. 59,) 
shews the mode of inflorescence in this Genus, 
by a single cone, rising like a Pine Apple, de- 
prived of its foliaceous top, from within the 
crown of leaves at the summit of the stem. 
The trunk of the Cycadeae has no true bark, 
but is surrounded by a dense case, composed of 
persistent scales which have formed the basis of 
fallen leaves; these, together with other abortive 
scales, constitute a compact covering that sup- 
plies the place of bark. (See PI. 58 and 59.) 
In the Geol. Trans, of London (vol. iv. part 1. 
New Series) I have published, in conjunction 
with Mr. De la Beche, an account of the cir- 
cumstances under which silicified fossil trunks 
of Cycadeae are found in the Isle of Portland, 
immediately above the surface of the Portland 
stone, and below the Purbeck stone. They are 
lodged in the same beds of black mould in which 
they grew, and are accompanied by prostrate 
* [nCurtis's Botanical Magazine, 1828, PI. 2826, Dr. Hooker 
has published an Engraving of a Cycas circinalis which in 1827 
flowered in the Botanic Garden at Edinburgh. See PI. 1. 
Fig. 33. 
t Copied from an engraving published by Mr. Lambert, of a 
plant that bore fruit at Walton on Thames, in the conservatory of 
Lady Tankerville, 1832. 
