478 OARBONIFEROUS KORMATTONS AND I-AITNAS oK COKORA IX i. 



Locality iind liorriati. San .luaii region (station •iMPj'J); tiiiddlc poi'tion of (lie 

 Hermosa formation. Onray (station 2l!)5); Ilcrinosa formation. Lcadvillc (Ustrict 

 (station '2257): lower i)ortion of tlie Weber formation. 



Fhillu'Sia TRINUCLEATA llcrrick. 



PI. X, figs. 1.1, Hi. 



1SS7. I'liilti/isia trhmcle.ata. Herrick, Si i. Lab. Denigoii t'niv., T>\ill., vol. L', ji. M. pi. 1, tig. 2:!; 

 pi. 2, fig. ■A2; pi. 3, tig. 21. 



Coal Measure;^: Flint Ridge, Ohio. 

 1888. Froetus truiudcatuii. Vogdes, New York Acad. Sci., Ann., vol. 4, ]i. si, pi, 2. figc. 7-9. 



Waverly group [in error]; Flint Ridge, Licking County, Ohio. 



Two or thre(> specimens from Colorado seem to l)elong to Herrick's species cited 

 above. None of the material is very good and that from station 2297 in the Crested 

 Butte district and from station 2:>1<> in the Durango quadrangle of the San Juan 

 region is so imperfect that I am not certain that it is conspecitic with the others. 



Locality and horizon. — San .Tuan region (station 2210); upper portion of the 

 Hermosa formation. Crested Butte district (station 2297?): Maroon forniation. 

 Leadville district (stations 2259, 2265); Weber formation. 



LEPEKDITIA Rouault, 1851 

 Leperditia sp. 



Ostracoda belonging to the genus Leperditia are \-ery abundant at station 2212 

 in the San Juan region, and station 2269 in the Leadville region. The most perfect 

 material is that from the San Juan region. The preAailing form is a transversely 

 elongate, nearly equilateral shell, which rarely attains a width of 2 millimeters. The 

 latter dimension is a little less than twice as great as the height. The eye spot must 

 be very small or very obscure, and I have not been able to detect it with certainty. 

 The surface appears to be quite smooth and solid. 



It is possible that among the shells included under this title more than a single 

 species may exist. 



Locality and ]i,orizon. — San Juan region (station 2212); middle portion of the 

 Hermosa formation. Leadville district (.station 2269); upper portion of the Weber 

 formation. 



' BAIRDIA McCoy, 1844. 



Bairdia sp. 



But a single species belonging to this genus has been described from American 

 Carboniferous rocks, Bairdia cestriensis Ulrich," and though from a higher horizon. 



"Cincinnati Soc. Nat. Hist., Jour., vol. 13, p. 210, pi. 17, figs, tia-c, 7a, b. 



