REPORT OF THE CHIEF ASTRONOMER 825 



SESSIONAL PAPER No. 25a 



feature of the Paskapoo series of the Red Deer river (1: pp. 9 and 51, p. 51), 

 as well as of the Lignite Tertiary of the Porcupine Creek and Great Valley 

 group in the western portions of Canada (52: p. 36). Recognizing the force of 

 the generalization of Sir William Dawson (14: iv., 73) to the effect that the 

 Miocene of Greenland, Spitzbergen and Alaska, as formerly regarded by Heer, 

 is in reality identical with the Fort Union of the United States, a view more 

 recently stated and adopted by Knowlton (38 : p. 240) and now universally 

 admitted, it now becomes possible to recognize the fact that the numerous 

 instances of the occurrence of this tree in Spitzbergen (22: p. 57), Grinnell 

 Land (24: p. 23), Siberia (25: p. 33), Saghalien (13: p. 22), Alaska (39: p. 378 

 and 51: p. 214), as well as in Greenland itself (23: p. 60; 26: p. 9; 28: p. 463, 

 and 29: p. 89), give unquestionable proof of its wide spread and abundant occur- 

 rence throughout the Eocene of America as well as of Europe. While, therefore, 

 it is a form essentially typical of both the Eocene and Miocene, its greater 

 abundance in the former implies a vigor of development which it appears to 

 have lost in more recent times, although this does not of necessity permit 

 us to conclude that its presence in a given horizon is more indicative of the 

 one age than the other, a relation which must be finally established by collateral 

 evidence. 



Pinus columbiana does not, in itself, afford decisive evidence as to the 

 nature of the horizon from which it comes, but a review of the distribution 

 of the genus Pinus as now known may serve to suggest a reasonable conclusion. 



The genus Pinus, as given by Knowlton (37), embraces nineteen species, 

 most of which are defined specifically, ranging from the Dakota group through 

 the Cretaceous and Tertiary to the Pleistocene, where they become identified 

 with existing species. But to these we may add six species of Pityoxylon, some 

 of which are of Upper Cretaceous age, but most of which are Tertiary forms 

 most largely represented in the Eocene. More recently, Knowlton (35) has 

 also recognized the occurrence of the wood of Pityoxylon aldersoni and P. ame- 

 thystinum in the Upper Miocene of the Yellowstone National Park, while on 

 the other hand a recent publication by Ward has brought to light Pinus leei, 

 Font. (57 : p. 570), from the older Potomac Formation of Virginia, a case 

 which parallels that recorded by Heer of P. crameri, Heer, from the Kome beds 

 of Greenland. While some of the species of Pinus thus referred to are recog- 

 nizable through their wood structure, many others are known only through their 

 foliage, and, although these latter are designated by distinctive names, it is not 

 altogether certain that they are specifically distinct or that they are different from 

 species represented by other remains with which it is at present impossible to 

 identify them. A very large number of known species are represented wholly 

 by seeds, and this is particularly true of the numerous species which Heer 

 describes from the Eocene of Greenland and other Polar regions (22: Vols. 

 I.-VIL). Inasmuch as such seeds are representative of the fruit, they may 

 be directly connected with the cones, which are the chief means of recognizing 

 several species. Fontaine's Pinus leei from the Older Potomac of Virginia, as 

 described by Ward (57: p. 570), is thus distinguished, but it is to be observed 



