SOURCES OF THE PHOSPHATES. 347 



therefore highly probable that tlic rock, independent of fossils, contains them very gene- 

 rally, especiall}' 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 wliich Iiave been ol)tained by these 

 examinations ; and as they lead to practical results, and explain some facts which were at 

 first obscure, we think the lal)or and time bestowed upon them will not he 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 wliich 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-C8 



The composition of 100 grains, deprived of water and organic 

 matter, is 



Silex 11-68 



Alumina and peroxide of iron 0*43 



Carbonate of lime 86 -84 



Magnesia 0-64 



Potash and soda 0-48 



Fis. 3S. 



a a 



, 2_.- ^^:—e 



a 



100-07 



a a 



h 



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 TuUy limestone. The slopes J, 2, 3, consist 

 of a succession of terraces, which form the offset into Christian-hollow. 



44* 



