51 



Atiiy. 



the horizon of the Pittsburgh bed of the West. — XF, Monon- 

 gahela series of coal measures. — Found by J. J. Stevenson, in 

 the Loyalhanna gap, Westmoreland Co., Pa., numerous, with a 

 \^y^ Froductus elegans^iw subcarb. limestone. (KK, p. 291.) 

 (KKK, p. 311.) — XL In Perry Co., collected by Olaypole at 

 Vanderslice's quarry, Bloomsburg,in Hamilton ; numerous just 

 over top of Marcellus, near Huntingdon fn. 258). Catalogue 

 87-4(1).— F//7^/ VIII g, 



Athyris subtilita, (Hall, 1852, Stansbury's Expedition 



Z5 



Coal Measures.) Collett's In- 

 diana of 1883, page 136, plate 35, 

 figs. 6, 7, 8, belly, back and side 

 views of a typical example, nat- 

 ^291 uTol size; ^^. 9 back view of 

 larger specimen to which are cttUched two under valves of 

 Grani% modesta. — XIII— XVII. Widely known, the most 

 common and characteristic species of the Coal Measures, rang- 

 ing from base to summit, and into the Permian (Meek) ; from 

 Virginia to the Rocky Mountains; common in Upper and Mid- 

 dle, rarer in Lower Coal Measures. Dawson's Acad. Geology. 

 1868, page 291, figs. 88 a, h and c^ showing the spiral gills, which 

 give name to all the Spiriferidm. Occurs by millions in the 

 Lower Carboniferous limestone of Nova Scotia.^ — XL 



In Pennsylvania, abundant in Green Crinoidal limestone, 

 middle of Barren Measures (Pittsburgh Series) and in the 

 Black Crinoidal limestone, at Pittsburgh, and on the Cone- 

 maugh. (Reports K, p. 80; L, p. 35.) At Morgantown, W. 

 Va. in Deckert's creek shale under Mahoning sandstone, bot- 

 tom of Barren Measures (L, p. 36.) — in Lawrence, Beaver and 

 Butler Cos. in Ferriferous limestone (Q2, pp. 47, 106; Q3, p. 

 25; V, p. 147); also, in Conglomerate Xo. XI I, over Scrub- 

 grass coal in Mercer Upper and Lower limestone (QQ, dt3. 57, 



