Geological Re'poris on the State of Neio York. 15 



Unio, showing the cardinal and lateral teeth so distinctly as to remove all 

 doubt of the generic relations of the shell." 



"5. The fifth group consists of olive sandstone and slate, cut through 

 by Salmon river, in Oswego county. Intercalated strata of limestone 

 occur in the lowest portion of the series, full of brachiopodous bivalves. 

 This and the preceding red sandstone group correspond in geological 

 position with the fourth group in the slate system of Wales, described by 

 Professor Phillips."* 



" 6. Black limestone and shale of Trenton Falls, embracing the ' birds- 

 eye limestone' and 'calciferous sandrock' of Professor Eaton, and the 

 graywacke and slate of the Hudson river. The group clearly represents 

 the ' black shale inclosing beds of graywacke, flagstone and calcareous 

 slate, which, prolonged to the southwest, join themselves to the trilobite 

 beds of black limestone and calcareous flagstone at Llandeilo.'t In Mr. 

 Murchison's table, this group is termed ' Llandeilo flags.' " 



" It is a curious fact, that whilst the Calymene Blumenbachii, ceased 

 to exist in New York after the final deposition of the Trenton series, it 

 escaped into remote seas, and lived in the era of the Dudley limestone. 

 The Cryptolithus tessellatus, on the contrary, seems to have existed, and 

 to have become extinct, at the same periods in the seas which deposited 

 the rocks of Llandeilo and Trenton Falls. The plants and Crustacea 

 are peculiar to this group, and of the testacea, I have observed but two 

 species in a superior formation ; Delthryris striatula, and a small Orthis 

 resembling O. crumena, but having invariably four plaits or ribs on the 

 mesial elevation. Of the Polyparia, one only has been noticed above the 

 present series ; Cyathophyllum ceratites. All these fossils occur in the 

 second group, in the limestone of the Helderberg mountain." 



We are obliged to omit the illustrative catalogues of fossils and 

 the description of new species. 



Report of W. W. Mather of the First Geological District. 



Mr. Mather remarks : " Details and facts, belonging strictly to pure 

 scientific geology, will not be made public until the publication of the 

 final report. The object of the annual reports is to give publicity to such 

 facts and localities as may be of practical utility, so that benefit may be 

 derived from a knowledge of them, during the progress of the survey." 



The great mass of valuable facts adduced by Mr. Mather 

 scarcely admit of condensation, and all we can do is to make a 

 few selections illustrative of different heads. 



Encyc. Metrop,, article Geology, p. 568. t Ibid. 



