PART II. 



CATALOGUE OF TRILOBITES. 



For the geological horizons the author has used the 

 term "Cambrian" for the original Cambrian of Sedg- 

 wick, 1836 (Lower Silurian, Murchison). The term 

 " Taconic " is used for the zone with the Olenellus, Par- 

 adoxides, Olenus and Dicellocephalus faunse. " Silurian" 

 is used for Murchison's Upper Silurian. 



A SYSTEMATIC CLASSIFICATION OF THE GENERA. 



Agnostus Brcngniart, 1822. Hist. Crust. Foss., p. 38. Type, Agnostus 

 pisiformis Linne. Taconic. Cambrian. 



Sec. 1. Parvifrontes. Type, Agnostus brevifrons Ang. 

 Sec. 2. Lougifrontes. Type, A. punctuosus Ang. 

 Sec. 3. Limbati. Type, A. rex Barr. 



(B) Fallaces. Type, A. fallax Linrs. 

 Sec. 4. Lasvigati. Type, A. Icevigatus Dalm. 

 Sec. 5. Arthrorhachis. Type, A. tardus Barr. 



Shumardia Billings, 1862. Pal. Foss., vol. 1, p. 92. Type, Shumardia 



granulosa Bill. Taconic. 



Microdiscus Eramons, 1856. Am. Geology, vol. 1, pt. 2, p. 116. Type, 



M. speciosus Ford. Taconic. 



TRINCCLEID.K. 



Trinucleus Lhlwyd, 1698 (Cryptolithus Green, 1832). Murchison's Silu- 

 rian Syst., 1839, p. 659. Type, Trinucleus Jimbriatus Murcb. 



Cambrian . 

 Ampyx Dalman, 1826. Palaead., p. 53. Type, Ampyx nasutus Dalm. 



Cambrian. Silurian. 



Sec. 1. Brevifrontes. Type, Ampyx nudus Murch. 

 Sec. 2. Longifrontes. Type, A. nasntus Dalm. 

 Sec. 3. Lonchodomas. Type, L. domains Ang. 



Dionidas Barrande, 1847. Neues Jahrb. fiir Mineral., 1847, pt. 4, p. 391; 

 Syst. Sil. Boheme, vol. 1, p. 540. Type, Dionidce formosa Barr. 



Cambrian. 



1. Salteria Wyv. Thompson, 1864. Mem. Geol. Survey United King- 

 dom, decade xi, pi. 7, p. 1. Type, Salteria primceva Wyv. Thorn. 



2. Endyminia Billings, 1862. Pal. Foss., vol. 1, p. 93. Type, En- 

 dyminia meeki Bill. Cambrian. 



