LOWER CARBONIFEROUS FOSSILS. 527 



W. H. Weed. Crowfoot Ridge, Gallatin Range, top of bed 25, bed 26, bed 

 28, bed 29, bed 31; J. P. Iddings and G. M. Wright. South of Forellen 

 Peak, Teton Range; northwest slope of same; S. L. Penfield. Head of 

 Conant Creek, Teton Range; north of Owl Creek, northeast slope of Teton 

 Range; north of Owl Creek, north end of Teton Range; W. H. Weed. 

 Limestone bluff south side of Soda Butte Creek, northwest of Abiathar 

 Peak, Absaroka Range; J. P. Iddings. North side of north fork of Mill 

 Creek, Snowy Range ; J. P. Iddings and Louis V. Pirsson. Slide east side 

 of Gallatin River, below Fan Creek; under Quartzite Ridge, north side of 

 Burnt Fork. Beds of the age of the Waverly group, Wasatch Range, 

 Utah. 



Chonetes ornatus Shumard. 



PI. LXVIII, figs. 4«, U, 4c, id. 



Chonetes ornata Shumard, 1855 : Geol. Rept. Missouri, p. 202. PI. C, figs, la-lc. Keyes, 

 1894: Geol. Surv. Missouri, Vol. V, Pt. II, p. 53, PL XXXVIII, fig. 2. 



This also is a common species in the limestones of the Park, though 

 perhaps less abundant than the preceding. It differs somewhat from Shu- 

 mard's description, but agrees with specimens which, I have every reason 

 to believe, are correctly referred to Shumard's species. 



This form is often cpiite highly inflated with flat and depressed trian- 

 gular wings, a character not sufficiently emphasized by the author. 

 Another misleading point is that the species is described and figured as if 

 with submucronate alations. I have not seen this feature, at least to any 

 extent, in a series of specimens from both the Chouteau and Lithographic 

 limestones. Usually the cardinal angle is but slightly less than 90°. 

 However, it often happens that the anterior portion of the shell is concealed 

 by rock, so that the apparent shape is that of Shumard's figure. This con- 

 dition is cpiite deceptive, but I have rarely failed to find the nearly square 

 alar angle upon removing the superincumbent matrix. In its large forms 

 this species measures 13 mm. (over 6 lines) along the hinge line, and 

 8 mm., or nearly 4 lines, in length, while some imperfect examples evi- 

 dently exceed these dimensions. These data are derived from the study of 

 material from the Mississippi Valley. 



In the Yellowstone National Park representatives of Chonetes ornatus 

 are in nearly perfect accord with the larger forms coming from Missouri. 



