Frazer.] 



408 



[April 16. 



A specimen of Dolerite was taken from Beeler's farm, 2 miles S. W. of 

 York, York county, Pa., and submitted to Dr. F. A. Genth for analysis, 

 which is as follows : 



FEB, CENT. 



Silicic acid 52.53 



Phosphoric acid 0.15 



Titanic acid 0. 32 



Alumina 14.35 



Ferric oxide 5.93 



Ferrous oxide 5.45 



Manganous oxide trace 



Magnesia. — 7.99 



Lime.... 10.27 



Lithia faintest trace. 



Soda 1.87 



Potash. 0.92 



Copper trace. 



Sulphur 0.08 



Ignition 1.23 



Total 101.04 



Silicon 24.51 



Phosphorus.. 0.06 

 Titanium.... 0.19 

 Aluminum . . 7.65 

 Iron (from FeA) 4.15 

 Iron (fromFeO) 4.23 



Manganese . . 



Magnesium 

 Calcium. . . . 

 Lithium . . . 

 Sodium . . . 

 Potassium. . 



Copper 



Sulphur . . . 



4.79 

 7.33 



1.38 

 0.76 



28.24 



Oxygen. 



/ 28.02 



8.00 -i 



0.10 

 0.12 

 6.70 

 1.78 

 1.21 



3.20 

 2.94 



0.49 

 0.16 



0.08 



These constituents in chemical units give: 



Silicon 3. 



Titanium 0. 



P - 



Aluminum 0. 



Iron (from sesquioxide) 0. 



Iron (from protoxide) 0. 



Magnesium 0. 



Calcium 0. 



Sodium 0. 



Potassium 0. 



500 \ 

 015/ 



834"] 



222 



150 I 



399 j. 



366 



060 



019j 



Difference . 



5.515 



2.050 



1.465 



DOLERITE FROM BEELER'S. 

 Total units in rock 



11.133 



Chemical units of Si. and Ti. . . . 

 " " of basic radicals. 



Excess of units of Silicon, &c 



{Neglecting 3ul2)7iur) 



3.515 

 2.050 



1.465 



