found in the Oolite Quarries of the Isle of Portland. 399 



There is also a further analogy between this fossil species and the recent 

 Cycas *j viz. that in each case the outermost of the plated circles is the most 

 iiarrow of the tvvo^ and the cellular band between them is in both cases also 

 narrow. 



The eng-raving- of Cycas revoluta or Todda Pannaf, copied from Vol. iii. 

 Plate 21. of the Hortus Malabaricus^ exhibits many plated circles divided 

 from one another by narrow cellular bands, and these also are placed nearer 

 to the centre than to the circumference of the stem. 



It appears, therefore, that the external position and greater breadth of the 

 laminated circle, or circles, in the Cycadeoideas are the two most important 

 distinctions that can be drawn from the specimens before us, between the 

 structure of the stem in these extinct fossils and in the recent Zamia and 

 Cycas. These distinctions also afford a character whereby this family ap- 

 proaches nearer than the Cycadeae to the more perfect structure of dicotyle- 

 donous woods ; and in this respect it may be considered to hold a higher place 

 in the scale of vegetable creation, and to supply from the fossil world a link 

 that helps to fill the distant interval which separates the structure of the trunk 

 in the Cycadeae from that in the nearest existing family to them, viz. the Co- 

 niferae, which they perfectly resemble in the character of their organs of fruc- 

 tification. They however exhibit no traces of vessels such as radiate from the 

 centre and form the silver grain in the more perfect kinds of wood |. 



As yet, the stems of CycadeoideaB have been observed in no other formation 

 than the Portland stone, the geological position of which, in the upper part of 

 the oolite series, is well known from the descriptions of Mr. Webster and of 

 Messrs. Conybeare and Phillips, and no leaves have been noticed with them ; 

 but leaves of plants nearly aUied, and perhaps belonging to this family, have 

 been found near Whitby in the oolite formation, immediately above the 

 lias, in the imperfect coal strata of the Cleaveland Moorlands ; some of these 

 are engraved by Messrs. Bird and Young § : others are in a collection from 

 the same coal-field, made last year by Mr. Featherstonhaugh, and afford two 



* Plate XLVI. fig. 1. t Plate XLVT. fig. 2. 



:j: "Dans tout le regno vegetal, il n'est aucune famille des plantes qui ait plus de rapports 

 et de ressemblance avec les Coniferes, que celle des Cycadees. Ces rapports nous semblent si 

 grands, que nous pensons qu'il est impossible de distinguer ces deux families, ni par des caracteres 

 tires de leur fleurs, ni par des caracteres puises dans I'organisation de leur fruits. Les seuls 

 signes distinctifs qui existent reellement entr'elles, consistent uniquement dans leur port et la 

 structure anatomique de leur tige, que en efFet est fort differentcdans I'un et I'autre groupe." — 

 Richard, Memoire sur les Coniferes et les Cycadees. 1826. p. 183. 



$ Plate 2. fig. 2. and 7 ; and Plate 3. fig. 2. Geological Survey of Yorkshire Coast. 



