72 GENERIC AND SPECIFIC CHARACTERS. 



GENUS III. PINITES. 



A medullary axis of very large size ; woody tissue consisting of elon- 

 gated cellules ; medullary rays ; bark ; concentric circles usually indis- 

 tinct. Stems roundish or compressed, tapering, branched. Pith of ir- 

 regular polygonal cellules. Woody tissue in the transverse section pre- 

 senting the appearance of regular, parallel, radiating series of four-sided 

 subhexagonal cellules, with interspersed medullary rays. In the longitudi- 

 nal sections the cellules are seen to be greatly elongated, with oblique or 

 transverse dissepiments placed at great distances. Two of the walls, those 

 facing the medullary rays, are regularly reticulated, with two or three series 

 of hexagonal areolae. Those facing the pith and the surface are continuous, 

 and generally destitute of markings. The medullary rays in their trans- 

 verse section present irregular series of cellules, varying from one to five. 



The species of this genus have been found in the mountain-limestone 

 series, and in the coal-formation. 



1. Pinites Withami. Lindley and Hutton. 



(Pith undetermined). Concentric circles obsolete, walls of the elongated 

 cellules, with 2, 3, or 4 series of contiguous areola?, medullary rays of 2, 3, 

 or 4 series of cellules. 



Plate IV. Figs. 8, 9, 10, 11, 12. Plate V. Plate VI. Figs. 1, 2, 3, 4. 

 Plate VII. Figs. 1, 2, 3, 4, 5, 6. 

 Craigleith Quarry, near Edinburgh, in sandstone of the mountain-limestone 

 series. 



2. Pinites medullaris. Lindley and Hutton. 



(Pith large). Concentric circles distinct, walls of the elongated cellules re- 

 ticulated with 2, 3, or 4 series of contiguous areolae, medullary rays of 2-5 series 

 of cellules. 



Plate VI. Figs. 5, 6, 7, 8. Plate VII. Figs. 7, 8. 



Craigleith Quarry, in sandstone. 



