OF LOWER GREENS AXJ> PLANTS. 149 



Cedroxylon maidstonense, sp. nov. 

 [Plate XII, figs. 1 & 2 ; text-tigs. 41, 42, 43.] 



Diagnosis. Coniferous wood with well-marked annual rings, 

 trucheids, regularly arranged in series, up to about 50-80 p in 

 diameter ; bordered pits circular, generally in one row, a few 

 in adjacent pairs ; Sanio's rims well marked. Wood-parenchyma 

 absent or exceedingly scarce, liesin-canals absent. Medullary 

 rays principally 4-6 tracheids distant, nearly all uniscriate, a 

 few partly biseriate. Hays principally low, very few above 10 

 cells high. In tangential section " abietineau pitting'*' of end- 

 walls of ray-cells can be seen (but the pitting is not well enough 

 preserved to show in radial section) ; in the radial walls there 

 are several small pits per tracheid-field, chiefly 4-6 or more. 

 These small pits are oval or circular, but some seem slit-like and 

 with a border. 



HORIZON. Kentish Hag, Lower Greensand. 



LOCALITY. Iguariodon Quarry, Maidstone. 



TYPE. Secondary wood of oldish trunk, nos. 1769, and slides 

 1769 -1769c cut from it in 1912; British Museum (Nat. 

 Hist.). 



FINDER. W. H. Bensted, Esq., before 1850. 



DESCRIPTION. The new species is represented by a portion of 

 secondary wood, which appears to have been toward the outer 

 region of a fair-sized trunk, because of the remains of branch 

 bases and " knots," which still remain on one side of its outer 

 surface. The block is about 12 cm. long, by 5 X 4 cm. thick ; 

 the irregular core is well silicified and black in texture; the 

 outer coating, in which the cell-structure is not petrified, though 

 the woody appearance is retained, is whitish grey. 



TOPOGRAPBY OF THE STEM. Secondary wood alone is present. 

 In this growth-TMfft are well seen and are sharply marked 

 (PI. XII, fig. 1). The mass of the wood, however, is almost 

 entirely spring wood, the zone of autumn wood being exceedingly 

 narrow (as can be clearly recognised in the photograph, PI. XII, 

 fig. 1, ), and consisting of from 1 to 4 elements, while the spring 

 wood consists of from 9 to 34 elements in each growth-ring, the 

 maximum thickness of the rings being 2 mm. 



