484 KEPORT UNITED STATES GEOLOGICAL SURVEY. 



for my description, and which I rightly supposed to have been deformed 

 by compression or maceration. These leaflets are narrowed Into an 

 acumen, either long and slightly scythe- shaped, or short and straight. 



This brings me to the essential contribution of this year, which is 

 mostly from the same locality — Florissant, Colo. — indicated by some 

 contributors as South Park, by others as Oastello's Ranch, and thus 

 marked upon the habitat of the plants of the Tertiary Flora, as if all 

 these places were distant or separate localities. The specimens from 

 Florissant number about five thousand. I can only give now a short 

 and superficial account of the species which they represent. 



Their examination suggests at the outset some general remarks in 

 regard to the distribution of the vegetable remains preserved in this 

 formation, first by the total absence of certain types, then by the pre- 

 dominance of others. This local flora has not any leaves or even frag- 

 ments of leaves of Palms. Standing fossil trees are seen in the same 

 locality. In the specimens of silicified wood broken from the stumps, I 

 do not find any Palm wood. I have been informed, however, that trees 

 of this kind had been remarked there formerly, but had been totally 

 broken and taken away as curiosities by the numerous visitors of the 

 locality. I have been unable to ascertain the truth of that assertion. 

 The characters of the leaves refer them mostly to plants of a moderate 

 climate, and, as I have remarked in the Tertiary flora, to species of 

 mountains or of high valleys. Of the other division of the monocotyle- 

 donous also, there are scarcely any remains. The Glumacew only have 

 two fragments of leaves of Phragmites. From the lower orders of plants 

 we find there merely a few leaflets of Perns, two specimens, of a CJiara 

 and Salvinia Alleni, Lesqx. 5 this represented by a comparatively large 

 number of well-preserved specimens, whose characters slightly modified 

 do not present even sufficient differences for authorizing a separation in 

 varieties. Still more remarkable is the absence of fruits in the shales 

 of Florissant, which in its compounds has preserved the most delicate 

 organisms, feathers, insects, small flies, petals, even anthers and sta- 

 mens of flowers, but no hard fruits of any kind. 



The preponderance of remains of other species is not the less remark- 

 able, and perplexes the paleontologist who is trying to understand the 

 cause of that heaping of materials at Florissant, and the way and action 

 which has brought them there. For example, the leaves of Planera lon- 

 gifolia, and of its varieties, which appear to represent also Planera lingerie 

 and perhaps another species of the same genus, constitute there about 

 one-half of the preserved vegetable remains. We have at least two thou- 

 sand specimens of these leaves. Have they been brought by mountain 

 rivulets or torrents into a lake? We should then find the fruits as well 

 as the leaves, and the action of transfer seems scarcely probable in con- 

 sidering the very delicate texture of other organisms preserved. Have 

 the plants grown around the basin of water? The objection is the 

 same on account of the absence of fruits and of the vei-y fragmentary 

 state of the remains of Conifers, which, for Glyptostrobus at least, are 

 branches, leaves, and small cones, abundant enough, but all ground as 

 if they had been for a long time exposed to the movement of water or 

 to atmospheric influences. The presence of remains of flowers, of unripe 

 carpels of Ulmus, Acer, etc., would imply a deposition of vegetable mate- 

 rials in spring time, before the maturity of the seeds 5 and then to account 

 for the absence of fruits, we should have to suppose a gradual drying 

 up of the lake or swamp during the summer. In that case, as the 

 broken fragments of Conifers indicate a prolonged atmospheric action by 

 their decomposition, it would be possible to suppose the decomposition ■ 



