230 Geological Reports of the State of New York. 



organic remains. The Rochester and gypseous shales are given 

 as the equivalent of the Wenlock Shale of Murchison. The fos- 

 sils placed against Nos. 7, 8 and 9, belong to the lower rocks, as 

 Triarthrus and Isotelus to the Trenton limestones. Against No. 

 9 should stand the shell Pentamerus oblongvs, or if a trilobite 

 must be introduced, it can be neither of those mentioned, but 

 Asaphus longica.iidatiis. Where is the statement that the remains 

 against Nos. 5-9 have been found even as high as the Rochester 

 shale ? 



The limestone of Tally, or Tully limestone, is considered as 

 identified with the Aymesiry limestone of Murchison by two spe- 

 cies of shells, Avicula reticulata and Atrypa didyma. p. 31. 



The fronds of Fucoides are often very prominent, but the 

 structure like that of the rock in which they exist ; of other 

 plants, scarely more than impressions remain. The petrifying 

 material of the corals is commonly siliceous earth ; but of the 

 Crinoidea, is limestone, whether they lie in calcareous or siliceous 

 rock. p. 40. 



Several new genera and many new species are described, and 

 many yet remain for the final report, pp. 48-57. 



Several important corrections are announced. 



The Calymene Blumenbachii, as the trilobite in the Trenton 

 limestone was called, Mr. Conrad considers a new and unde- 

 scribed species; it is named by him Calyynene senaria, from its 

 place in so old a rock. It no longer is an instance of an animal 

 that "escaped into remote seas," and lived in a much later era 

 than its period of destruction here. " Calymene platys of Green" 

 is stated to be C. Blumenbachii, and to agree with it 'n\ place 

 also; so that this fossil is found where it ought to be, and no 

 longer throws uncertainty over the age of our rocks. 



The evidence is now thought conclusive by Mr. Conrad against 

 the existence of any fresh-water shells in the strata below the car- 

 boniferous, " in which Uniones occur in Pennsylvania." The 

 supposed Unio in the sandstone at Medina turns out to be some- 

 thing else, the Planorbis "probably a Bellerophon," and another 

 to belong to an allied genus. This correction is the more neces- 

 sary as these shells "are associated with two marine genera, Lin- 

 gula and Orthocera." Probably the existence of fresh-water 

 fossils in that sandstone had been a matter of high surprise to 

 most geologists ; the evidence decides the case. p. 41. 



