180 Agricultural Geology of Onondaga County. [April, 



the water lime series, from which the analyzed specimen was 

 taken, is not that part of the series which is used for cement. 

 The whole series from the Niagara limestone to the Onondaga, 

 show that they are strictly magnesian deposits; they show too, 

 that the magnesia predominates only in the soil below the Onon- 

 daga limestone. For cereals we regard magnesia as important as 

 any of the inorganic matters, and observation we believe will bear 

 us out in the position that all those soils which have magnesia are 

 decidedly preferable to those which are destitute of it. 



Two hundred grains of the soil upon the Onondaga limestone, 

 when submitted to the action of cold water alone, dissolved 1.34 

 grains; of this, .68 was organic matter, and ,66 saline. It was 

 taken from a wheat field, in stubble, east of Manlius Square. It 

 evidently produced a heavy crop. 



The composition of the soil upon the water limes are repre- 

 sented by the following analysis. The soil had been only culti- 

 vated for a few years, and is full of the fragments of the broken 

 underlying rocks: 



Hygrometric water, ----- 3.00 



Vegetable or organic matter, - - - 13.00 



Silex, 54.00 



Protoxide of iron and alumina, - - - 9. 10 



Carbonate of lime, ----- 15.63 



Magnesia, 4.24 



Sulphate of lime, - - - - - 1.16 



100.13 



In this sample of soil the quantity of organic matter is greater 

 than usual. It was taken from the first terrace, formed by the thin 

 bedded water limes at Manlius Centre, about sixty feet above the 

 Erie canal. It is the immediate debris of fhe rock mixed with 

 much undecomposed vegetable matter, and is not wholly derived 

 fiom the rock beneath, as is often the case with the soils upon 

 the plain below, where the gypseous shales lie beneath. 



One hundred grains of the soil of the cultivated field of Mr. 



