XLIV] PROTOPICEOXYLON 231 



rays are said to consist exclusively of tracheal tissue^. Pine 

 needles and cones have been obtained from the amber beds. 



The Fossil forests of the Yellowstone Park include examples 

 of Pityoxylon trees some of which have been described by Knowl- 

 ton^ and FeUx^, but unfortunately the anatomical details are not 

 as a rule well preserved. The most striking exposure of the 

 Tertiary (probably Miocene) trees is on the slopes of Amethyst 

 mountain (fig. 712), where a succession of forests is represented 

 throughout the 2000 ft. of strata. Felix describes a species, 

 Pityoxylon fallax, chiefly interesting from the point of view of a 

 comparison between the stem and root wood of the same tree: 

 the elements of the root are in general larger than those in the 

 stem. Knowlton gives an account of P. Aldersoni and P. ame- 

 thystinum, species which may be identical : the pits on the tracheids 

 and medullary rays are seldom preserved, but the occurrence of 

 both vertical and horizontal resin-canals is clearly shown. 



VIII. PROTOPICEOXYLON. Gothan. 



Protopiceoxylon exstinctum Gothan. The generic name Proto- 

 piceoxylon was proposed for some Lower Cretaceous wood from 

 King Charles Land* possessing Abietineous characters, intermediate 

 between Cedroxylon and Pityoxylon in having only vertical resin- 

 canals, at least in uninjured wood. The anatomical features of 

 the type-specimen are complicated by the occurrence of additional 

 resin-canals in wounded portions of the stem. It is difiicult to 

 determine the precise extent of the traumatic influences, but 

 the presence of callus-wood healing a wound leaves no doubt as 

 to the correctness of Gothan's conclusion that certain features 

 are abnormal and due to the effects of wounding. In the species 

 P. exstinctum are also included specimens from Spitzbergen^ 

 and some of the material on which Cramer^ founded his species 

 Pinites cavernosus : the later specific name is not retained on the 

 ground that the original diagnosis is incorrect and it was only 

 after examining sections of the type-specimen that Gothan recog- 

 nised the true nature of Cramer's species. 



1 Conwentz (90) A. PI. ix. fig. 2. 



2 Knowlton (99) p. 763, Pis. cvi. — cvin., oxii. — cxv., oxvin., oxix. 



3 Felix (96) p. 254. * Gothan (07^) p. 32, figs. 16, 17 ; PI. i. figs. 2—6. 

 5 Gothan (10) p. 15, PI. n. figs. 5—8 ; PI. ra. figs. 1^, 6—8. « Cramer (68). 



