NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 29 



*Meteoraspis brevispinosa 

 Tricrepicephalus thoosa 

 Undetermined cranidium No. 2 



Most of these species are represented in higher beds except Blountia 

 alexas and Meteoraspis brevispinosa, which were not found in the 

 highly fossiliferous, higher portions of the same limestone unit. Mary- 

 villia arion is very rare in the above faunule, whereas it becomes 

 abundant in higher beds. 



A rather large faunule was collected near Rogersville, a short dis- 

 tance from locality cnk/1, in beds approximately 45 feet below the top 

 of the lower limestone unit of the Nolichucky, hence about 90 feet 

 above the beds cnk/1. At other localities no fossils were observed at 

 this horizon. The faunule (collection cnm/2) includes : 



Blountia arcuosa 

 Blountia montanensis 

 Coosella planicauda 

 Coosia alethes 

 Coosina amage 

 Coosina ariston 

 Dresbachia amata 

 Kingstonia inflata 

 Llanoaspis walcotti 

 Madarocephalus laetus 

 Maryvillia arion 

 Meteoraspis mutica 

 Tricrepicephalus thoosa 



Finally, the youngest faunule of the Crepicephalus zone is well rep- 

 resented at numerous localities. It occurs either near the top of the 

 massive lower limestone unit of the Nolichucky, or in thin limestone 

 beds near the base of the overlying shale. The transition between the 

 Crepicephalus and Aphelaspis zones may occur either within the upper 

 portion of the limestone unit, or within the lower part of the overlying 

 shale. In some sections, such as at Big Creek, it is possible that the 

 faunizone boundary coincides with the lithologic contact. The species 

 observed at localities cnn/1, cnn/2, cnn/3, cnn/4, cnn/5, cnn/14, 

 cnn/15, cnn/16, cnn/17, cnn/19, and cnmV20 are listed below. These 

 collections are lumped together, since age differences between them 

 appear insignificant. 



Amiaspis erratica 

 *Amiaspis obsolescens 

 * Blountia arcuosa 



Blountia lata 



Blountia montanensis 



Blountiella, sp. undet. 



Coosella, sp. undet. 



