REPORT OF TEE CHIEF ASTRONOMER 827 



SESSIONAL PAPER No. 25a 



conclusion is emphasized by the fact that the somewhat large number of species 

 originally described by Heer (26: 46, 52), from Greenland and Spitzbergen, 

 are all of Eocene age. Of these latter, Cyperacites paucinervis, Heer., is also 

 found in the Eocene of Vancouver island (13: iv. 144). In the enumeration 

 of the fossil flora of the Yellowstone National Park, Knowlton (35: p. 779.) 

 shows that of the four species known there, three are definitely referable to the 

 Eort Union group, while only one is referred to the Miocene. Finally, Ward 

 (58: p. 464) indicates similar relations when in his synopsis of the Laramie 

 group, he enumerates four species, all of which he shows to be exclusively of 

 Eocene age. From this summary it becomes obvious that Cyperacites is essen- 

 tially and typically an Eocene genus, the chief aspect of which is Lower Eocene. 

 The only exception to this which has come under my notice, is the case of an 

 undescribed species recorded by Sir William Dawson in his description of 

 specimens from the Kootanie group at Anthracite, B.C., (5: p. 91), but this 

 reference is a doubtful one, as the species does not correspond with the usually 

 accepted characters of the genus, or with those of the existing genus Cyperus, 

 and I therefore exclude it from further consideration in this connection. 



The reference to Potamogeton in the present instance is based altogether 

 upon the fruit, but there seems little reason to question the correctness of this 

 conclusion. Knowlton records seven species of Potamogeton (37), five of which 

 are from, the later Tertiary, but two are from the Eocene. Ward (58) shows 

 that there are fifteen species of Potamogeton in the Eocene Flora, two of which 

 are also common to the Senonian; while Heer defines no less than nine species 

 from the Tertiary of Europe (31: L, p. 102; II., p. 88; III., p. 170), and five 

 from the Eocene of Greenland (29: I, and 23, VII), Spitzbergen (27: 10 and 

 22), and Siberia (24), from which it would appear that as we now know it, 

 this genus is essentially distinctive of the Eocene age. 



Phragmites is a form of plant remains which is nowhere clearly defined, 

 though in a general way it may be recognized without much doubt. Precisely 

 what it embraces with respect to either genus or species, it would be impossible 

 to say at present, though in a general way it may be said to embrace fragments 

 of broad leaves, more rarely fragments of stems or even of rhizomes of Mono- 

 cotyledonous plants. The fragments of leaves are not always separable with 

 certainty from other Monocotyledonous leaves with .similar characteristics, 

 while the stem fragments are clearly differentiated from Cyperacites. The 

 rhizomes are usually sufficiently well characterized to be recognized with cer- - 

 tainty. There is no correlation between these various forms relegated to a 

 common genus, but when recognizable their characters are sufficiently definite 

 to permit of using them for stratigraphical purposes. An examination 

 of the North American distribution of the genus shows a somewhat wide 

 range. Thus, P. cretaceus, Lesq., represented by both leaves and 

 rhizomes, is a constituent of the flora of the Dakota group (42: p. 34, and 

 43: p. 37). Dawson has reported the leaf of P. cordaiformis, Dn., from the 

 Upper Cretaceous of Vancouver island (9: p. 26). Newberry reports fragments 



