32 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 



stratigraphic position of the type collection from Saltville, Va., is un- 

 known, but in Tennessee the species was found to occur always in the 

 same relative position to other forms of Aphelaspis, excepting the un- 

 usually early occurrence mentioned above. It was collected at Three 

 Springs (cnr/15), Smith Hollow (cnq/16, cnr/16), Lost Creek 

 (cnq/4), Hurricane Hollow (cnr/17 = Oder's coll. No. 2), and 

 Washburn (cnq/20). Associated species are Glaphyraspis declivis, 

 G. oderi, and Blountia mimula, the last found only at Hurricane Hol- 

 low. 



This is the latest known occurrence of Blountia in Tennessee. In 

 view of this fact and other faunal changes, it seems proper to designate 

 the strata so far discussed as the lower portion of the Aphelaspis zone. 



The overlying beds, here assigned to the middle Aphelaspis zone, 

 hold various faunules characterized by several species of Aphelaspis 

 and related genera. These assemblages do not appear exactly in the 

 same order in the different sections, hence we may assume that they 

 are essentially of the same age. In the Washburn section, the earliest 

 of these faunules (collection cnqV20) consists of Aphelaspis wash- 

 burnensis and Glaphyraspis declivis. This is followed by an assem- 

 blage of Aphelaspis camiro, A. laxa, and A. quadrata, recognized at 

 several localities (U.S.N.M. locality 120, Shields Ridge; cns/15, 

 cnsV15, Three Springs; cns/16 (= Oder's collection No. 13), Smith 

 Hollow; cnr/20, cnrV20, Washburn). The Washburn section yields 

 from somewhat higher beds (cns/20) a very characteristic assemblage 

 of Aphelaspidella macropyge, Aphelaspis arses, A. rotundata, and 

 Paraphelaspis vigilans. 



However, at Lost Creek we encounter in ascending order a bed with 

 rare Aphelaspis cf. laxa (cnqV4), followed by one with A. rotundata 

 (cnq'V4). Above the latter are Hmestone beds (cnr/4, cnrV4) with 

 an abundance of Aphelaspidella macropyge, accompanied by Aphelaspis 

 arses, Aphelaspis cf. lata, Cheilocephalus sp., and Paraphelaspis vigi- 

 lans. The still higher beds cns/4 yielded rare Aphelaspis camiro and 

 A. laxa, in addition to other species to be mentioned later. In the Three 

 Springs section, above a bed (cnr'/lS) with Aphelaspis laxa, collec- 

 tion cns/15 yielded Aphelaspis camiro, A. laxa, A. quadrata, A. wash- 

 burnensis, and Aphelaspis, sp. undet. (the last two not associated in 

 the same stratum with the other three). The still higher beds ens VI 5 

 and cns'VlS yielded Aphelaspidella macropyge, Aphelaspis arses, A. 

 rotundata, and Paraphelaspis vigilans. These findings indicate that al- 

 though the Aphelaspis camiro-laxar-quadrata and the Aphelaspidella 

 macropyge-Aphelaspis rotundata-Paraphelaspis vigilans assemblages 

 were never observed in the same bed, each may occur either below or 

 above the other. 



