Aphelaspis buttsi 



lata 



transversa 



minor 



walcotti 



washburnensis 



camiro 



laxa 



quadrata 



rotundata 



palmeri 



arses 



inermis 



arsoides 



tumifrons 



tarda 



punctata 

 Aphelaspidella macropyge 

 Paraphelaspis vigilans 

 Dyt remacephalus angulatus 



strictus 



sulcifrons 

 Dunderbergia longifrons 



tennesseensis 

 Cheilocephalus brevilobua 



brachyops 



sp, undet. 

 Coosella perplexa 

 Tricrepicephalus, sp. undet. 

 Glaphyraapis parva 



ornata 



declivis 



oderi 

 Blountia bristolensis 



mimula 

 Pseudagnostus communis 



LOWER 



MIDDLE 



Fig. 1. — ^Range of trilobite species in the Aphelaspis zone of Tennessee. 



