SOURCES OF THE PHOSPHATES. 
347 
therefore highly probable that the rock, independent of fossils, contains them very gene¬ 
rally, especially the softer kinds. 
The Tully limestone was also analyzed, and found to contain a large amount of phos¬ 
phates. 
In conclusion, we are quite satisfied with the results which have been obtained by these 
examinations ; and as they lead to practical results, and explain some facts which were at 
first obscure, we think the labor and time bestowed upon them will not be lost or useless. 
In the vicinity of Christian-hollow, and indeed through a wide region of country, there 
are many marl ponds, some of which are situated in a manner similar to the small green 
lakes of which something has been said already. In connexion with the foregoing analyses, 
I deem it proper to give the composition of the marl which has been obtained from one of 
these ponds in the town of Preble. The annexed cut, fig. 38, will convey an idea of the 
mode in which they are distributed over the country. 
ANALYSIS. 
Organic matter. 3-01 
Water (dried at 212°)...... 5*68 
The composition of 100 grains, deprived of water and organic 
matter, is 
Silex_ _ _ . 
•68 
Alumina and peroxide of iron_ 
_ O' 
■43 
Carbonate of lime... 
.86' 
•84 
Magnesia. 
-. O' 
•64 
Potash and soda__ 
_ 0 
•48 
100 
•07 
/, 
A north and south section, running in the range of five or six marl ponds or small lakes, and extending between five 
and seven miles, or from the south end of Christian-hollow, to a point near Cortlandville. The lakes are above 
the Green lakes of Manlius, being mostly in a position superior to the Tully limestone. The slopes i, 2, 3, consist 
of a succession of terraces, which form the offset into Christian-hollow. 
44 
