402 GEOLOGICAL SUEVEY OP THE TEERITOEIES. 



base, borders and teeth tliicker aud membranaceous or cartilaginaceous; 

 tbree-nerved from the base, lateral nerves thick, much divided, divis- 

 ions branching also like the secondary veins, which are nearly at equal 

 distance from the primary ones and parallel, few, opposite, all the branches 

 going up to the points of the teeth. The species has a close relation to 

 V. marginatum^ so abundant at Black Butte. It has the same type of 

 nervation, but is, however, very different by the thicker substance of 

 the leaves, the thicker primary and secondary veins, the three-lobate 

 form of theleaves, aud the truly serrate (oot dentate) borders. The base 

 of the leaf also is abruptly turned downward or nearly truncate. The 

 species is a very fine one, and it is regrettable that it is represented as 

 yet by a single fragineutary specimen. 



Habitat. — Golden ; communicated by A. Lalces. 



OoRNUS Studeei, Heer. 



Leaves variable in size, entire, oval-lanceolate, taper-pointed or acu- 

 minate, roundetl in narrowing to the petiole; lateral veins simple, par- 

 allel, curving in passing up to near the borders, along which they join 

 each other in festoons; fibrillae distinct, in right angle to the veins, or 

 sometimes diverging upward. This species is represented by numer- 

 ous leaves of different size, the largest at least 14 centimeters long, 

 with 12 to 14 pairs of veins, (the base-is broken,) the small leaves only 

 6 J centimeters long with 9 to 10 pairs of lateral veins. . The lowest veins 

 are always closer than the upper ones; these near the top become nearly 

 parallel to the midrib. The substance of the leaves is thickish and 

 somewhat coriaceous. 



Habitat. — Golden. It is also common at Evanston. 



CORNUS HOLMESII, sp. nov. 



The upper part of an ovate-lanceolate entire leaf, with secondary 

 veins thin, very distant, alternate, much curved in passing up in an 

 acute angle from the middle nerve toward the borders. The point of 

 the leaf is broken. Though the specimen is fragmentary, it represents 

 evidently a Gornus specificall.y distinct from the other fossil species by 

 the great distance of the secoudarj^ veins. By this character only it is 

 distantly related to G. Buchi, Heer. , 



Habitat. — Bituminous shale, Coal Creek, Colorado, TF. H. Holmes. 



CoENUS OEEIFEEA, Heer. 



Leaves round or broadly oval, entire ; rounded upward to the point, 

 and also downward to a short, curved petiole; medial nerve thick; sec- 

 ondary veins deep, though narrow, inflated at their point of union to 

 the midrib, which they join in a broad angle of divergence, arched in 

 ascending to the borders. The substance of the leaves is thickish, the 

 surface rough, secondary veins all simple, effaced close to the borders, 

 the lowest in right angle and marginal. The uervilles are close, oblique 

 to the veins, simple or branching. 



Habitat. — Golden. 



Kelumbium tenuifolium, sp. nov. 



Leaves exactly round, peltate from the middle, small, 8 to 9 centimeters 

 in diameter, of a thin texture, with flat, undulate borders ; primary 

 nerves 13, equal and at equal distance, thin or narrow, nearly simple or 

 sparingly branching, crossed at right angle by uervilles, which by rami- 

 fication form large square areas. The leaf shows the upper side some- 



