THE FLORA. 



163 



Occurrence: Laramie formation, Gehrung's 

 coal mine, near Colorado Springs, Colo, (type) ; 

 Coal Creek, Colo.; Marshall's coal mine, at 

 Marshall, Colo.; Hoyt's coal mine, 1 mile south 

 of Golden, Colo.; and Crow Creek, 25 miles 

 northeast of Greeley, Colo. Denver formation, 

 3,000 feet east of Douglas coal mine, Sedalia, 

 Colo. Dawson arkose, Pulpit Rock, near Col- 

 orado Springs, Colo. 



Dombeyopsis trivialis Lesquereux. 



Plate XIII, figure 3; Plate XIV, figure 3. 



Dombeyopsis trivialis Lesquereux, U. S. Geol. and Geog. 

 Survey Terr. Ann. Kept, for 1872, p. 380, 1873; 

 idem for 1873, pp. 382, 404, 1874; idem for 1876, 

 p. 514, 1878; Tertiary flora: U. S. Geol. Survey 

 Terr. Kept., vol. 7, p. 255, pi. 47, fig. 3, 1878. 

 [Lesquereux's original figure is here reproduced as 

 PI. XIII, fig. 3.] 



The type specimen of this species is pre- 

 served in the collections of the United States 

 National Museum (No. 379) and is found on 

 the hard white sandstone characteristic of the 

 Laramie at Golden, Colo. The species has not 

 been detected in any of the subsequent col- 

 lections from this locality, but in the material 

 from a locality north of Colorado Springs there 

 occurs the fragment shown in Plate XIV, fig- 

 ure 3, which appears referable to this species. 

 Although only a fragment of the basal portion 

 of one side, it appears to agree with the type in 

 essential details. It is, for instance, deeply 

 heart-shaped at the base, with several large 

 lobes on the margin. The nervation consists 

 of three principal ribs, with a lighter basal 

 pair which makes it in effect hve-ribbed. 

 Branches from lateral strong ribs pass to the 

 marginal lobes, and probably the basal pair of 

 ribs also terminated in more or less pronounced 

 lobes. 



Do7nhei/opsis trivialis is undoubtedly closely 

 related to D. platanoides Lesquereux,"-' from 

 which it differs, according to Lesquereux, in 

 being smaller, in having tlie nervation less 

 deeply marked, with all the nerves thinner and 

 with fhe secondaries placed in the upper part 

 of the leaf at a great distance above the base. 

 The two lower veinlets coming from the top of 

 the petiole indicate a tendency for the leaf to 

 become five-ribbed. Whether these are char- 

 acters of sufficient weight to separate these 



«3 Lesquereux, Leo, The Tertiary flora: U. S. Geol. Survey Terr. Kept., 

 vol. 7, pi. 47, figs. 1, 2, 1878. 



two forms must remain for more complete ma- 

 terial to settle. 



The present species is also like Dombeyopsis 

 obtusa Lesquereux "* in general shape and ner- 

 vation but differs in having the margin lobed 

 instead of entire. It is possible that when a 

 sufficient amount of material can be obtained 

 it may show that all three forms are referable 

 to a single species, but for the present they 

 must be kept apart. 



Occurrence: Laramie formation; Golden, 

 Colo, (type), collector not known but probably 

 F. V. Hayden; opposite sand-lime brick works 

 about 4 miles north of Colorado Springs, Colo., 

 collected by A. C. Peale and G. I. Fmlay, 1908. 



Dombeyopsis? sinuata Knowlton, n. sp. 



Plate XXV, figures 1, 2. 



Dombeyopsis? sirmata Knowlton [nomen nudum], U. S. 

 Geol. Survey Bull. 696, p. 243, 1919. 



Leaf evidently thin and membranaceous, 

 apparently broadly ovate, well rounded to a 

 slightly cordate base and probably a rather 

 obtuse apex; margin undulate-sinuate; mid- 

 rib very thick, especially below, provided 

 above with several pairs of thin, alternate, 

 remote secondaries tliat fork and send branches 

 to the margmal undulations; just above the 

 base of the blade there is a pair of opposite, 

 strong ribs that arise at an angle of about 45° 

 and pass up for more than half the length of 

 the blade, each with five or six rather strong 

 secondary branches that are at right angles 

 to the midrib and apparently end in the mar- 

 ginal teeth: below the large ribs is a pair of 

 thin ribs that bear thin secondary branches on 

 the lower side; finer nervation can not be 

 satisfactorily made out. 



The example showai in figure 1 is in a poor 

 state of preservation, being folded around the 

 rock on which it is imprinted and more or less 

 effaced by rubbing. As nearly as can be 

 made out it is broadly ovate, about 15 centi- 

 meters long and nearly 12 centimeters wide. 

 It is in effect five-ribbed; the midrib is very 

 thick and strong, as are a pair of ribs which 

 arise at an angle of 45° some distance above 

 the base and pass up for apparently more than 

 haK the length of the blade. Below this 

 pair of strong ribs is a second pair of much 

 more slender ribs which arise at nearly a right 



« Idem, pi. 47, figs. 5, 6. 



