OF LOWER GTIEENSAND PLAXTS. 211 



separation can be judged from Gothan's own criteria : of these 

 genera he says ; 



" Markstrahltiipfel podocarpoYd bis typisch gross - eiporig. 

 Meist nur 1-2 Tiipfcl pro Kreuzungsfeld. Harzparenchym 

 + hjiufig. 



(a) Markstrahltiipfel podocarpoid "j Podocarpoxylon^ 



bis tcilweise eiporig J Gothan. 



(7>) MarksirahUupfel typisch ei- | Phyllodado.vylon, 



porig J Gothan." 



Podocarpoxylon woburnense, sp. nov. 

 [Hate XX, figs. 1 & 2 ; text-figs. 60, 61, 62, 63.] 



Diagnosis. Podocarpoid wood with well-marked growth- 

 rings, bat with a narrow zone of autumn wood. Tracheids 

 fair-sized, up to about 35-55 /j. in diameter. Bordered pits 

 rather irregularly rounded, or true circles, principally in one 

 row, but sometimes with pairs of pits 011 the same level ; pits 

 vertically isolated or adjacent, Sanio's rims apparent in many 

 places. Resin-containing wood-parenchyma frequent all through 

 the wood, cross-walls horizontal, with very slight constriction of 

 cell-lumen. Medullary rays all uniseriate, 1-6 tracheids distant/, 

 the great majority low. Hay-cells apparently uniform as regards 

 size and thickness of wall, though some contain noticeably more 

 resinous contents than others. Ray-cells with thickened smooth 

 walls, abietinean pitting absent, end-walls curved or at an angle 

 in radial view, nearly straight in horizontal section. One largo 

 pit (sometimes two) per tracheid-field in radial walls ; pit-pore 

 roughly circular or oval, with a narrow border in some cases. 



HOEIZON. Lower Greensand. 



LOCALITY. Woburn, Bedfordshire. 



TYPE. Block of wood, no. V. 5456, and V. 5456 a to 

 V. 5456 r, the slides cut from it in 1912; British Museum 

 (Nat, Hist.). 



FINDEK. H. Yeasey, Esq., before 1898. 



CO-TYPE. V. 5451 and slides V. 5451 a-c cut from it in 



1912. 



DESCRIPTION. The type-specimens are two blocks from the 

 same locality, both wedges of secondary wood. One is about 



p2 



