516 FL(»KA OF THE I.AKAMIE (iUorP. 



The data may be coudeusecl in the followiug form : 



Systematic groups. 



All plants 



Cryptogams 



Cellular 



Vascular 



Pb£eno;;ams 



GymDosperms 



Aus;ii»spi'rnis 



Monocotyledons 



Dicotyledons ... 



Ai)etala; — 



PolypetaliT . 



Gamopetala; 



Laramie. 



Number, i Per cent. 



323 



48 

 13 

 3.") 



275 

 18 



257 

 31 



226 



119 

 84 

 23 



100.0 



14. g 



4.0 

 10.9 

 85.1 



5.6 

 79.5 



9.6 

 69.9 

 36.9 

 26.0 



7.0 



Senonian. 



Number. Per cent. Number. Per cent. 



97 

 18 

 79 



265 

 43 



222 

 23 



199 



116 



Eocene. 



100.0 



26.8 



5.0 



21.8 



879 

 143 



100. 

 16.2 

 10.1 



6.1 

 83.8 



6.6 

 77.2 

 12.2 

 65.0 

 27.6 

 29.9 



7.6 



An examination of these percentages shows that little light is thrown 

 by them npon the relative age of the Laramie group. While in the Se- 

 nonian, as theory would require, the Oryi)togams have a higher propor- 

 tion than in the other formations, it will be observed that they have a 

 smaller proportion in the Laramie than in the Eocene, which is contrary 

 to theory. This anomaly, however, is caused by the irregular represen- 

 tation of the cellular Oiyptogains, which generally have increased with 

 the later epochs and do not represent the waning types of the ancient 

 floras. The vascular Cryptogams, however, do this, and it is to them that 

 we imi.st look for the confirmation of the theory, if it is to be contirmed. 

 We find that it is here confirmed with sufiBcient accuracy, the Laramie 

 occupying a position intermediate between the Senonian and the Eocene, 

 though considerably nearer to the latter. 



In the (jymuospenus we find the same anomaly as in the total Cryp- 

 togams, which in both cases is evidently due to the great predominance 

 in the Laramie group of dicotyledonous forms. That group is, however, 

 exce])tionally rich in Monocotjledons, approacliing the Eocene in this 

 respect, while this type is meagerly developed in the Senonian. It is 

 the great predominance of palms in the lower Laramie that has led Mr. 

 Lesquereux to insist upon its Eocene facies, and this is certainly evi- 

 dence not to be ignored. It is known that this type reaches its maximum 

 development in the Eocene, and that to its predominance the special 

 character of the Eocene flora is largely due. If, however, the Laramie 

 groui) includes the Fort Union beds in one great deposit, with an exten- 

 sive north and south range, its combined flora will certainly greatly 

 reduce the percentage of these Eocene types, for we must recollect, and 

 I hope soon to demonstrate this fully, that, so far as now published, the 

 flora of the southern districts is given a wholly undue prominence and 

 that of the northern remains as yet for the most part undescribed. Still, 

 this is an anticipation which is out of place here, since the object of 



