342 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



began aud ended their existence with this mass, we may mention 

 (Hall, Pal. i. 37) the Maclarea, Raphistoma, and Scalites, of which 

 generic analogues are scarcely known higher. The same was the 

 case with the two species of Bucania and two of Orthoceras. 



The organic affinities of this stratum with Trenton Limestone are 

 close. Fragments of crinoidal columns, differing in no respect from 

 the Trenton-Limestone species, are found in this rock at Watertowu, 

 New York (Hall, Pal. i. 51). 



Fossils typical. — Columnaria alveolata; C. sulcata; Gorgonia? aspera; 

 Streptelasma expansa ; Retepora gracilis ; R. incepta ; Strictopora glome- 

 rata ; S. fenestrata ; Actinocrinus tenuiradiatus ; A. sp. ind. ; Orbicula 

 deformata; Atrypa acutirostra; A. altilis; A. dubia; A. plena; A. plici- 

 fera ; Ambonychia my tiloides ; Maclurea magna ; Raphistoma plenistria ; 

 R. var. parva ; R. staminsea ; R. striata ; Capulus auriformis ; Murchi- 

 sonia abbreviata ; Pleurotomaria antiquata ; P. bi-angulata; P. spec. ind. ; 

 Metoptoma dubia; Bucania rotundata; B. sulcatina; Lituites convolvens ; 

 Orthoceras, n. s.; O. moniliforme ; O. rectangulatum ; O. sub-arcuatum ; 

 O. tenuiseptum ; Ormoceras gracile ; O. tenuifilum and var. distans ; 

 Endoceras gemelliparum ; E. longissimum ; E. multitubulatum ; E. sub- 

 centrale; Gonioceras anceps (Hall and Owen); Asaphus marginalis ; A. 

 obtusus ; Ceraurus, sp. ind. ; Illaenus arcturus ; I. crassicauda ; Isotelus 

 can ali s. 



Fossils occurrent in Europe. — Columnaria alveolata ; C. sulcata; Glvpt- 

 aster brachiatus ; Ambonychia nudata ; Maclurea magna ; Murchisonia 

 angulata ; Pleurotomaria angustata ; Raphistoma striata ; Scalites angu- 

 latus ; Orthoceras commune ; Bellerophon sulcatinus ; a species of Bucania. 



Fossils recurrent in New York. — Chsetetes lycoperdon ; Strom atocerium 

 rugosum ; Glyptaster brachiatus; Murchisonia angustata; Orthoceras 

 duplex; O multiseptum; O. vertebratum ; Illsenus crassicauda, &c. See 

 Table of Recurrency. 



Birdseye Limestone. 



Mineral Character. — It is in thick layers, evenly bedded ; vertical 

 joints well marked. Its colour is bluish-grey, or light-dove. It is 

 fine-grained or compact ; fracture conchoidal. We find it crystalline 

 in patches. It is generally a pure limestone ; in places siliceous. 

 (Emmons, p. 108.) 



Transition. — From Chazy Limestone to Birdseye the transition is 

 commonly gradual ; but on the Mohawk River, and at Essex on Lake 

 Champlain, the transition is abrupt, a part being wanting to connect 

 the two : thus showing, according to Vanuxem, a lapse of time between 

 the completed deposition of the older stratum and the commencement 

 of the newer. 



Place. — This deposit is well developed in the counties of Mont- 

 gomery, Herkimer, Oneida, and Lewis (Vanuxem), and, according 

 to Emmons (Rep. p. 382), " forms an irregular belt through Jefferson 

 County from east to west, with a breadth of at least ten miles. Its 

 northern outcrop, on an east and west line, passes through Depauville 

 and a point two miles south of Evans's Mills, on the great bend of 

 Indian River. From this point it runs to the great bend of the 

 Black River, and thence to a point two miles S.W. of Carthage." 

 Its disappearance at the south under the Trenton Limestone is along 



