GEOLOGY OF THE FOURTH DISTRICT. 



ORGANIC REMAINS OF THE ONONDAGA SALT GROUP. 



No. 25.— No. 54, page 137. 

 Fig. 1. Cornulites, n. s. 

 Fig. 2. Orthoceras lave, H. 

 Fig. 3. Loxonema Boydii, H. 

 Fig. 4. EuompJialus sulcatus, H. 



Fig. 5. Delthyris ? 



Fig. 6. Atrypa ? 



Fig. 7. Avicula triquetra, H. 

 These all occur at a single locality, and but one other shell has been seen in the group. 

 Two of these species are not satisfactorily ascertained. 



ORGANIC REMAINS OF THE WATERLIME GROUP. 



No. 26. — No. 58, page 142. 



Fig. 1. Delthyris plicatus. Orthis plicatus, (Geol. Report Third District.) 



Fig. 2. Avicula rugosa, Conrad (Annual Reports). 



Fig. 3. Tentaculites ornatus. (See Silurian Researches, p. 628, pi. 12, f. 25.) 



Fig. 4. Littorina antiqua, Conrad (Annual Reports). 



Fig. 5. Atrypa sulcata, Vanuxem (Geol. Report). 



Fig. 6. Cytherina alta, Conrad (Annual Reports). 



ORGANIC REMAINS OF THE PENTAMERUS LIMESTONE. 



No. 27. — No. 25, Report of the Third District, page 117. 

 Fig. 1. Pentamerus galeatus. Atrypa galeata, Dalm. 

 Fig. 2. Euomphalus profundus, Conrad (Annual Geol. Report). 

 Fig. 3. Atrypa lacunosa? This fossil is considered by Mr. Conrad as identical with the 



Terebratula lacunosa of Europe. 

 Fig. 4. Lepocrinites Gebhardii. The stems, one covered by a thick calcareous coating, and 



the other showing the rings. 



ORGANIC REMAINS OF THE DELTHYRIS SHALY LIMESTONE. 



No. 28. — No. 27, Report of Third District, page 122. 

 Fig. 1. Strophomena punctilifera, Conrad. 



Fig. 2. Strophomena radiata, Conrad. These fossils occur in the Delthyris shaly limestone 

 in central New-York, but at the west the S. punctilifera holds a higher position. 



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