114 



Report of the State Geologist, 



6. Liorhynchus mesacostalis, Hall. (c) 



7. Productella cf. speciosa, Hall. Fragment. (r) 



8. Leptodesmt Hogersi, Hall. (it) 



9. Aulqpora, sp. (rr) 



10. Grmmd stems and segments. (r) 



11. Spirophyton, sp. (rr) 



12. Microdon (Cypricardella) gregarius. Hall, (rr) 



Possibly this specimen is not from this locality as the rock is 

 lithologically somewhat different. 



13. Spirifer fihibt'iatiis (Con.), Bill. (?) (r) 



14. Atrypa reticularis (Lin.), Dalm. (rr) 



15. Chonetes setigera, Hall. (rr) 



16. Amboccelia umbonata (Con.), Hall. (r) 



1 7. Phacops rana (Green), Hall. (rr) 



This exposure of fossiliferous rocks is regarded by the writer as con- 

 taining the early species of the Ithaca epoch of the Chenango valley region. 

 There is no question that on the same hillside about 288 feet lower than 

 this fossiliferous shaly sandstone, is the top of the Tully limestone, while the 

 intervening rocks, as far as exposed, are thin bluish shales in which fossils are 

 very rare; shales that agree in all respects with those of the lower Portage 

 or Sherburne formation of central New York. Near Ithaca, from the base 

 of the lowest rocks referred to the Ithaca group down to the top of the 

 Genesee shales is 250 feet, which is nearly the thickness of the Sherburne for- 

 mation in the Chenango valley. This section with others near Smyrna and 

 Sherburne clearly show that the fossiliferous beds twelve miles farther south 

 near Norwich and extending along the river valley to Oxford, are not in the 

 Hamilton formation, but are of later date. 



The accompanying picture of a portion of the Fall Creek gorge at 

 Ithaca, gives an excellent idea of the lithologic characters of the formation 

 at its typical locality. 



XVIII A 2 . Along the bed of Pleasant brook, about one and three- 

 quarter miles above Smyrna village, and three-fourths of a mile below Upper- 

 ville are excellent exposures of coarse, arenaceous shales which contain fossils 

 in abundance. 



TropidoleptuH carinatus (Con.), Hall, is particularly plentiful and there 

 are many specimens of large Lamellibranchs. The species are those of the 

 Hamilton formation, as will be seen from the following list : 



