THE FLORA. 



99 



two Magnolias, the Fraxinus, and possibly the 

 Zizyphus, and about its border the two palms 

 may have had their home. 



The conifers do not offer very definite 

 evidence and, moreover, are so rare in individ- 

 uals that they could hardly have been a con- 

 spicuous element. It is probable that they 

 /grew on adjacent higher ground and found 

 their way into the deposits through the agency 

 of streams. Growing with them on higher 

 ground may well have been the Oornus, 

 Quercvs, Juglans, Hicoria, Rhamnus, Hedera, 

 Ilex, etc., which complete the picture. 



We may now proceed to draw some perhaps 

 tentative conclusions as to the climatic con- 

 ditions under which the Laramie flora may be 

 presumed to have existed. From the abundant 

 presence of coal and the apparent require- 

 ments of the majority of the plants enumerated, 

 it is beyond question that there must have 

 been an abundance of moisture. It also 

 appears naturally to follow from the presumed 

 requirements of the flora that the climate was 

 warm, at least warm temperate. 



GEOLOGIC RELATIONS OF THE FLORA. 



Naturally one of the most interesting and 

 important phases of this study of the Laramie 

 flora is the bearing it may have on the inter- 

 pretation of the age and stratigraphic relations 

 of the beds in which it occurs. As -has been 

 so abundantly shown in the section on the his- 

 torical treatment of the term Laramie, this 

 term has been so bandied about' that at one 

 time its significance as a stratigraphic designa- 

 tion had been practically lost or at least greatly 

 obscured. Much of the earlier paleobotanic 

 work on the flora was rendered unavailable for 

 the reason that practically every student had 

 a different concept of the Laramie, and this 

 could only lead to irreconcilable confusion. 

 The present study was undertaken in the hope 

 that by taking a comparatively small area and 

 thoroughly working up its flora, data might 

 be obtained that would serve as a basis for 

 comparison elsewhere. It remains to be seen 

 how far this desire has been realized. 



The flora of the Laramie in the Denver Ba- 

 sin comprises 129 forms, of which 74 are here 

 described as new to science, 8 forms have been 

 regarded as too fragmentary or obscure to war- 

 rant being named specifically, and 47 forms 

 have been previously named and described. It I 



is to be noted, however, that although the pro- 

 portion of new forms may seem to be large, 

 many of them have been known to the writer 

 for years; in fact, the descriptions of perhaps 

 more than half of them have been in manu- 

 script since about 1895 and have been utilized 

 in discussions of this and related floras. 



BELATIONS TO THE MONTANA FOBMATIONS. 



The Laramie flora, as might perhaps be ex- 

 pected, is on the whole most closely related, 

 either by identical or obviously related spe- 

 cies, to the Montana flora; yet with adequate 

 collections there should be no difficulty in sepa- 

 rating them. As the unconformity which sepa- 

 rates the Laramie from the Arapahoe and Den- 

 ver formations is believed to be the same as 

 that which separates the Vermejo from the 

 overlying Raton formation in the Eaton Mesa 

 region, it might be presumed that there should 

 be a close correspondence between the Laramie 

 and 'the Vermejo, but a critical study of the 

 floras does not bear out this presumption. At 

 first it was thought that only a single species 

 (Rhamnus salicifolius) Was common to the two 

 formations, but later study discloses the fact 

 that there are five or six species that occur in 

 both. Inasmuch as there are 106 species in 

 the Vermejo and 129 in the Laramie, however, 

 the relationship obviously is not very strong. 

 The species in common are as follows : 



Sequoia reicheibachi (Geinitz) Heer. 

 Sabal moitana Knowlton. 

 Myrica torreyi Lesquereux. 

 Ficus dalaiatica Ettingshausen. 

 Ficus trinervis Knowlton. 

 Rhamnus salicifolius Lesquereux. 



Of these species, Sequoia reichenbachi has an 

 almost worldwide distribution and ranges in 

 age from Jurassic to Upper Cretaceous, and it 

 is therefore pf no importance as a close horizon 

 marker. The known presence of this species 

 in the Laramie rests on a few more or less 

 doubtful fragments, though if correctly identi- 

 fied its rarity has, of course, no bearing 1 in the 

 present consideration. Sabal rnontana is a 

 very large leaved species, perhaps the largest- 

 leaved Rocky Mountain form, and as a con- 

 sequence it is rather rarely found in perfect 

 condition. There is little doubt, however, 

 that it occurs in both Vermejo and Laramie. 

 Myrica torreyi, 'though occurring mainly in the 

 Montana, is a widely ranging form and has even 



