472 GEOLOGY OF THE DENVER BASIN. 



the purpose of showing the bearing of the plants on the question of age 

 and the differentiation of the horizons, the complete presentation being 

 reserved for the forthcoming monograph on the Flora of the Laramie and 

 Allied Formations. 1 



As nearly as can be made out from the scattered data available at the 

 present time, the flora of the Laramie and Denver formations within the 

 Denver Basin consists of 240 species. These are distributed as follows: 

 Undoubted Laramie. 2 98 species; undoubted Denver/ 5 150 species; Sand 

 Creek, near Denver, 10 species; and Sedalia, 20 species. Of these 240 

 species 83 are confined to the Laramie, 130 to the Denver, and 3 to the 

 other two localities. These exact figures may have to be slightly changed 

 when the final revision is made, but that can not possibly change the 

 essential point — namely, that these two formations are strikingly distinct, 

 at least within the Denver Basin. 



It should not be forgotten, however, that some of the species that are 

 confined to either the Laramie or Denver within this area are found outside 

 of it enjoying a more or less marked vertical range — that is, they are not 

 all restricted to the Laramie or the Denver or its equivalent. It would be 

 of interest to trace out these resemblances, but the data are not in shape to 

 admit of this being done with satisfaction, and it also is deferred to the 

 monograph. 



Turning now to the consideration of the peculiarities of these two 

 floras, a number of interesting facts are made out. The Laramie was 

 especially rich in figs, about 15 species having been described. Ferns, 

 oaks, and buckthorns (Rhamnus) were abundant. There was a single fine 

 species of bread-fruit tree (Artocarpus Lessiyiana (Lx.) Kn.) and at least 

 two palms. The conifers were rare in both formations. 



The Denver flora is much richer, both in species and types. The figs 

 continued in increased abundance, and some were of large size. The genus 

 Plantanus was abundant both in species and individuals, as was the genus 

 Populus. 



1 In preparation. 



-The localities are Erie mines, Marshall mine, Coal Creek, Hoyt's coal mine near Golden, Mount 

 Carbon near Morrison, and Murphy's coal hank, on Ralston Creek. 



'Golden, andesite deposits, Table Mountain, Green Mountain, Denver. 



