734 IDAHO MINING DISTRICTS. 



the horns is about 17 mm . The length from base to tip of central promi- 

 nence is 16 mm . The length of the horns is about 7 mm , and the length 

 of the central prominence about 4 mm . 



Thus far only two specimens of Trapa have been described from 

 North America T. borealis Heer, 1 from the Eocene of Port Graham, 

 Alaska, also detected by Dawson in the Laramie of Red Deer and 

 Rosebud rivers, Canada, and Trapa (?) microphylla Lx., 2 described 

 from Point of Rocks, Wyoming, and since detected near the mouth 

 of the Yellowstone River in Montana, in the Yellowstone National 

 Park, in the Ceratops beds of "Wyoming, and along the Red Deer and 

 Rosebud rivers in Canada. Some doubt attaches to the correctness 

 of the reference of the last to Trapa, as the specimens are leaves or 

 leaflets only; but as they have been found by Dawson associated with 

 fruit, it may be correct. 



The ordinary form of T. borealis, as described and figured by Heer 

 (loc. cit.), is quite different from the one in hand, being very thick 

 and obtuse at base, with irregular horns and a greatly enlarged cen- 

 tral projection. One of Heer's figures (op. cit., fig. 11), however, is 

 quite like ours in shape, but is more than twice the size. 



The species from Idaho is perhaps more like T. silesiaca Gopp., 

 described from Schossnitz, Silesia, and also detected by Heer in Por- 

 tugal. 3 It is about the same size, but differs slightly in the slenderer 

 horns and entire central prominence. 



Locality: Idaho City, Idaho. 



TRAPA ? OCCIDENTALIS n. sp. 

 PL Oil, fig. 7b. 



Fruits two-horned, or in effect three-horned, the lateral horns slen- 

 der, acute, at right angles to the central prominence or horn, which 

 is nearly twice the size of the lateral ones; body of the fruit but little 

 prolonged below the plane of the lateral horns, slightly wedge-shaped. 



These fruits are decidedly anomalous. They are deltoid or trian- 

 gular in general outline. The width is 2 cm , each lateral horn being 

 5 or 6 mm in length and 2 mm in width at the base. - The central pro- 

 jection is 1.5 cm in length and about 5 mm in width at the base. 



I am much in doubt as to whether these fruits should be referred 

 to the genus Trapa. They are found in the same piece of matrix as 

 the one previously characterized, and in fact, as may be seen from 

 the figure, one of them overlaps one of the horns of T. americana. 

 Close association of unconnected fossils does not, of course, argue 

 affinity, but these are so close together and have such a general 



1 PI. Poss., Alaska, p. 38, PI. VIII, figs. 9-14 



5 Bull. U. S. Geol. and Geogr. Surv. Terr., Vol. I, p. 369, 1875; Tert. PI., p. 295, Pl.'LXI, figs. 

 16-lTa; Ward, Bull. U. S. Geol. Surv. No. 37, p. 64, PI. XXVII, figs. 3-5, 1887. 

 3 Contr. PI. Poss. Portugal, p. 37, PI. XXII, fig. 11, 1881. 



