OF LOWER GREENS AND PLANTS. 309 



inner face of the inner wood-ring) shows clearly the 

 characteristic lenticular ridges and hollows due to 

 the wide medullary rays and xylem-strands. " Potton 

 Sands," Lower Greensand ; Leighton Buzzard. 



Morris Coll., 1863. 



Cycadeoidea buzzardensis, sp. nov. 

 [Text-figs, 98-100.] 



Diagnosis. Species founded on vegetative trunks, showing 

 pith, wood, and leaf-bases ; the inner tissues petrified to show 

 imperfectly preserved anatomical details. Trunk probably 

 cylindrical, probably capable of reaching more than 24 cm. in 

 diameter. Petiole-bases apparently covering the stem, arranged 

 spirally, measuring 3'5 cm, horizon tally and 1'5-1*.8 cm. verti- 

 cally, much drawn out laterally. From three to eight or more 

 distinct cylinders of secondary wood surround the large pith. 

 The woody cylinders eaeh having a maximum thickness of about 

 1 cm., composed of radiating zones of secondary wood. Between 

 the wood-cylinders are zones 2-4 mm. thick of different tissue 

 (phloem ?). Tracheids in regular radial series, averaging 20-85 p 

 in diameter ; [nature of pitting not recognisable]. Cortex very 

 narrow, leaf-bases not massive, cortex and leaf-bases together 

 measuring less than 2 cm. in radial thickness. 



HOKIZON, " Potton Sands," Lower Greeneand; probably 

 derived from "Wealden. 



LOCALITY, Sand-pit just outside Leighton Buzzard. 



TrpB. Co-types, V. (5598 and V. 5895, British Museum (Xat. 

 Hist.). 



GENERAL DESCRIPTION. The species is described from two 

 specimens in the Museum, probably of different ages, and there 

 are two other pieces of different individuals. The specimens, like 

 C. Yatesii, are all alike in colour and texture, being preserved 

 in a dark lirnonite, very close and heavy, and opaque in section. 

 They are too incomplete to give an accurate indication of their 

 diameter. One of the type-specimens shows both pith and 

 cortex, and must have been at least 14 cm. in diameter; the 

 other consists only of wood-rings, concentrically arranged and 

 therefore all from one side of the specimen, and is without 

 either pith or cortex. An estimated diameter of 24 cm. is the 



