GEOLOGY OF THE FOURTH DISTRICT. 



ORGANIC REMAINS OF THE MARCELLUS SHALE. 



No. 39. — No. 71, page 180. 

 Fig. 1. Orthoceras subula turn, II. Bloomfield, Ontario county. 

 Fig. 2. Strophomena setigera, H. Avon, Livingston county. 

 Fig. 3. Strophomena mucronata, IT. Avon. 

 Fig. 4. Strophomena pustulosa, H. Avon. 

 Fig. 5, Avicula muricata, H. Avon. 

 Fig. 6. Avicula Icevis, H. Avon. 



Fig. 7. Avicula equilatera, II. Bloomfield, Ontario county. 

 Fig. 8. Orthis nucleus, H. Avon. 

 Fig. 9. Orbicula minuta, H. Avon. 

 Fig. 10. Tentaculites fissurella, H. Avon. 



Fig. 11. Atrypa limit arts, Orthis limitaris, Vanuxem (Geol. Report). Le Roy, Genesee 

 county. 



ORGANIC REMAINS OF THE HAMILTON GROUP. 



No. 40. — No. 78, page 196. 

 Fig. 1. Bellcrophon patulus, H. Kidder's ferry, Cayuga lake. 



Fig. 2. Microdon bellastriata, Conrad (Jour. Acad. Nat. Sci. Vol. 8, p. 247, pi. 13, fig, 12). 

 Fig. 3. Cucullca opima, H. Seneca lake shore. 

 Fig. 4. Nucula? oblonga. Seneca lake shore. 

 Fig. 5. Nucula lineata? Phillips (Palaeozoic fossils, p. 39, pi. 18, fig. 64). Cayuga lake 



shore. 

 Fig. 6. Tellina? ovata, H. Seneca lake shore. 

 Fig. 7. Nucula bellatula, H. Ogden's ferry, Cayuga lake. 

 Fig. 8. Cypricardia truncata. {Cypricardites truncata, Conrad, Jour. Acad. Nat. Sci. Vol 8 



p. 244, pi. 12, fig. 17. See Geol. Yorkshire, pi. fig. ) 

 Fig. 9. Modiola concentrica, II. (See Modiola semisulcata, Silurian researches, pi. 8, fig 6.) 



No. 41. — No. 79, page 198. 

 Fig. 1. Turbo lineatus, H. Ovid, Seneca lake shore. 

 Figs. 2 and 3. Delthjris mucronata, Conrad (Annual Report of New-York Geol. Survey, 



1841, p. 54). Eighteen-mile creek. 

 Fig. 4. Atrypa prisca. (Terebratula affmis, M. C. t. . T. prisca, Von Bucii ; T. reti- 

 cularis, Brown, Lcthea Geognostica. Atrypa reticularis, Dalman. A. affinis, 

 Silurian Researches.) Eighteen-mile creek. 

 Fig. 5. Atrypa concentrica, Brown (Lethea Geog.) Eighteen-mile creek. 



35 



