PALEONTOLOGY OF NEW-YORK. 
The occurrence of such vast numbers of lingulas in this rock renders 
extremely interesting and significant the late discovery of Mr. T. S terry 
Hunt, that the shells of all lingulae are composed of phosphate of lime. 
This offers an explanation of an apparent anomaly before observed in 
regard to these shells, showing that the conditions favorable to or admit¬ 
ting their existence may preclude that of other molluscs. Thus we have 
conclusive evidence of the occurrence of lingulae in the Potsdam sand¬ 
stone, often in great numbers, and extending over an area of country more 
than one thousand miles from east to west, and from three to five hundred 
miles from north to south; while not a single other shell has been pu¬ 
blished to the world from the same rock over this wide area. The harsh 
arenaceous beds of this ancient sea deposit, from Canada to the Mississippi 
river, we find, with few exceptions, nearly destitute of calcareous matter, 
and capable only of supporting the existence of this enduring little animal, 
covered with its phosphatic shell, itself almost as hard as the siliceous 
grains amid which it lies entombed. 
The Potsdam sandstone, in Iowa, is often composed of rounded or oolitic 
granules in its higher beds; and the beds of passage to the succeeding 
rock are frequently of such a character that we must suppose them to have 
been largely formed from silica in solution, or from gelatinous silica. 
The investigations made in the Canadian Geological Survey show that 
the Calciferous sandstone is, in some parts, more highly fossiliferous than 
in any previously known localities. The new forms, however, are few, and 
present no wide departures in type from those before recognized. The 
Ophileta (Euomphalus ? ) complanata is sometimes extremely abundant, 
hundreds of individuals occurring in a single locality. 
These variations are doubtless in a great measure due to the different 
characters assumed by the rock in different places. In the States of Wis¬ 
consin and Iowa, and the Territory of Minnesota, this rock has proved 
quite as poor in fossils as it is in the State of New-York, and has furnished 
fewer species compared with the area of its outcrop and exposure. In that 
part of the country, the rock is highly magnesian, and is likewise much 
