LOWER CARBONIFEROUS FOSSILS. 507 



This species occurs at the south side of Soda Butte Creek, northeast 

 of Abiathar Peak, Absaroka Range, associated with Loxonema delicatum and 

 a number of other gastropod forms too imperfect for description (see 

 aute, p. 482). 



Formation and locality : Three Forks limestone, south side of Soda 

 Butte Creek, northeast of Abiathar Peak, Absaroka Range; J. P. Iddings. 



LOWER CARBONIFEROUS. 

 PROTOZOA. 



ENDOTHYRA Phillips, 1845. 



Endothyra baileyi var. parva n. var. 



PI. LXXI, figs. 13a, 136, 13c. 



This form is known only by microscopic sections and therefore very 

 inadequately ; but the correctness of the reference to Endothyra seems 

 unquestionable, and I am even in doubt whether it is varietally distinct 

 from Hall's species. So far as my observations go, it is never much over 

 half the size of Endothyra baileyi, 1 and is more simple — i. e., less numerously 

 chambered. Although these characters are ordinarily of questionable diag- 

 nostic value, appearing as it does in quite different associations, the Western 

 form seems worthy to be classed as a distinct variety. And it is not improb- 

 able that a study of the shell under auspices more favorable than by 

 microscopic sections will more fully justify the distinction. This form 

 should be compared with E. bowmani Phillips and E. lobata Brady, which 

 Brady 2 considers to be the same as E. baileiji. They are less robust and 

 more simple forms. 



Formation and locality: Madison limestone, White Mountain, Absaroka 

 Range; Arnold Hague. Amphitheater east of Bannock Peak, Gallatin 

 Range, bed 30; Snake River Valley, west of Two Ocean Plateau; W. H. 

 Weed. 



1 See PI. LXXI, figs. 12a, 126. 



2 Pakeontographical Soc, Vol. XXX, p. 92, PI. V, figs. 1-4. 



