IN THE STRATA OF THE LIAS AND OOLITIC SERIES. 65 



mentioned. It appears to me simply that differences in the thickness of 

 slices, or of different parts of the same slice, produce differences in the as- 

 pect of the cellules, such as we observe, under similar circumstances, in all 

 the fossil stems hitherto examined. Excepting the lacuna?, or turpentine 

 vessels, therefore, I have observed no vessels properly so called in this spe- 

 cies, any more than in the others which I have examined. 



Fig. 8. Represents part of a longitudinal section parallel to the medul- 

 lary rays. The specimens which I possess are so small, and the markings 

 in this direction are so obscure, that I have scarcely succeeded in detecting 

 the real nature of the tissue. However, I have distinctly seen it in one 

 portion to be as represented in the figure. The elongated cellules are 

 very regular, and here and there present acute terminations. Their walls 

 seem covered with minute granules or areola? of different sizes, and not ar- 

 ranged in regular series. The medullary rays are regular and distinct 

 These minute irregular reticulations are similar to those presented by spe- 

 cimens from the English lias, and may be the ultimate vesicles of the 

 cellular tissue, or transparent granules of resinous or other matter. In 

 other species they are co-existent with the large areolae characteristic of 

 Peuce, and as the tissue in every other respect is similar to that of the lias 

 trees, I am inclined to consider it not as a Pinites, but a Peuce. 



Fig. 9. Represents part of a longitudinal section parallel to the bark. 

 In this section, the structure is more distinctly seen in the specimen which 

 I possess. The only thing remarkable that it exhibits is the very small 

 size of the medullary rays, which always consist of one series of cellules, ge- 

 nerally not more than from two to five cellules being placed above each 

 other, and frequently a single one forming the ray. The sides of the cel- 

 lules are also covered with minute areolae of different sizes, and irregularly 



With Peuce eggensis, I conclude my examination of the fossils of the 

 lias and oolite, any remarks arising from a comparison of the species and 

 genera described, may be with propriety transferred to the next section. 

 Previous to entering upon this part of my task, however, it will be proper 



