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sentative of the old. red sandstone or Devonian system of Great Bri- 
tain, in consequence of its inclosing remains of Holoptychius and 
Coccosteus. ‘This deposit is succeeded in descending order by others, 
referable, on account of their testaceous remains, to the lower part of 
the same system, and these are again underlaid by limestones and 
shales, especially at Lockport and Rochester, charged with Ptilo- 
dictya lanceolata and other Silurian corals and fossils. The lowest 
deposit alluded to by Mr. Hall is the Medina sandstone. The: fol- 
lowing sectional list, in descending order, is copied from his com- 
munication :— 
Red sandstone. 
Sandstone and shale, abundance of fossil shells. 
Shale, with thin layers of sandstone ; Fucoides, abundance ; few 
shells. 
Green and black shale, several hundred feet, thick. 
Black shale. 
Moscow shale. 
Encrinal limestone. 
Ludlowville shale. 
Thin mass, with Bellerophons. 
Shale. 
Thin limestone, with fossils. 
Marcellus shale. 
Limestone, with hornstone. 
Onondaga limestone. 
Onondaga saliferous group, containing gypsum and salt-springs. 
Lockport limestone. 
Rochester shale. 
Limestone. 
Green shale, with fossils. 
Pentamerus limestone. 
Green shale and iron ore. 
Red and grey sandstone, Medina sandstone*. 
With respect to the Onondaga saliferous group, Mr. Murchison 
points out its extremely low geological position, resting upon a cal- 
careous stratum, which has been proved by its organic remains to be 
the equivalent of the Wenlock limestone ; and he states that it is 
of higher antiquity than the oldest salt-bearing beds of Russia. Mr. 
Murchison also alludes to the great value of Mr. Hall’s communica- 
tion in proving the wide application of the paleozoic succession esta- 
blished in Great Britain. — 
April 21.—Joseph Cox, Esq., of Wisbeach, and Hugh Fraser, 
Esq., of Newton, near Inverness, were elected Fellows of this So- 
ciety. 
* For detailed accounts of the New York Devonian and Silurian Systems 
and their Organic Remains, see the Geological pee of the State for 
1838, 1839, 1840. * 
