38 DESCRIPTION OF FOSSIL TREES DISCOVERED 



distinct medullary rays, of considerable breadth. No appearances of con- 

 centric circles have been observed. 



Fig. 2. Represents part of a longitudinal section of the same plant 

 parallel to the medullary rays. Viewed in this direction, the tissue is also 

 very regular, consisting of elongated cellules, which are quite straight, with 

 walls marked generally with three or two series of circular bodies, always 

 placed at some distance, usually about a semidiameter from each other, and 

 seldom or never occupying the whole breadth of the cellules. The me- 

 dullary rays are distinctly seen. 



Fig. 3. Represents part of a longitudinal section perpendicular to the 

 medullary rays. The tissue is composed of elongated cellules, very regular 

 and parallel. Their walls, viewed in this direction, are continuous, and des- 

 titute of markings. The medullary rays have a breadth usually of four, or 

 from three to five series of cellules. 



The separation of the circular markings of the walls of the elongated 

 cellules renders this plant different from the genus Pinites, in which the re- 

 ticulations are contiguous, and occupy the whole breadth of the cellules. In 

 the genus Pinus, and in other recent Coniferae, the circular bodies or pores 

 occur in a single series. The plants in question cannot therefore be, with 

 strict propriety, referred to the order, although they, as well as the species 

 of Pinites, must have been very closely allied, and the former even more so 

 than the latter. As no fossil plant exactly resembling this has been de- 

 scribed by authors, I propose instituting for its reception a genus bearing 

 the name of Pitus, which is a Greek noun analogous to Pinus. The plant 

 of which Figs. 1, 2, and 3. of Plate VIII. are representations, is evidently 

 of the same species as the Lennel Braes fosssil, figured in Plates III., IV., 

 and VII., and affords a much more characteristic specimen of it. The Pi- 

 tas antiqua, then, is the first species of this new genus. A second has been 

 found in the same place. 



Fig. 4. Represents part of a transverse section of another fossil found at 

 Tweed Mill, in which the ordinary structure of the recent Coniferae and the 

 fossil Pinites is distinctly seen. This species is very remarkable for the 



