1 84 



NEW YORK STATE MUSEUM 



Si0 2 . . 

 AI2O3. 

 Fe 2 3 . 

 FeO... 

 MgO.. 

 CaO. . 

 Na 2 0. 

 K 2 0. . 

 H 2 + 

 H 2 0— 

 CO2... 

 TiO... 

 P 2 5 .. 



S 



MnO.. 

 BaO. . 

 SrO... 



SiOiSoLinHCl. .. 



n 



Sol. 



3.00 



3-o8 



73.66 



3-17 

 0.56 

 1 .01 

 0.07 

 0.13 

 1.80 

 0.22 

 0.31 

 0.13 

 tr. 



0.13 

 0.03 

 0.02 



87.44 



Insol. 



11 .91 

 0.31 

 0.32 



0.07 

 0.08 

 0.04 

 0.08 



tr. 

 tr. 

 o. 12 



12 



Sol. 



12-75 



100. 19 

 0.06 



2-59 

 4-17 

 41 .21 

 3.60 

 6.81 



14-55 

 0.19 



0.07 



2 .61 



0.60 



17.00 



0.22 



0.22 



0.46 

 0.03 

 0.17 



94-50 



Insol. 



11a 



(n.61%) 



4 -56 

 0.18 

 0.13 



0.06 

 0.05 

 o. 11 

 0.10 



tr. 



0.07 



0.05 



5-31 



25-83 

 26.52 



120. 



(14-48%) 



27.3O 

 4.82 



15-53 



17.89 



28.80 



24.86 

 10.42 



18.03 



99.81 

 0.04 



100.00 



100.00 



11 Spherules of oolitic ore, Clinton, N. Y. Princeton Catalog no. 6107 

 E. W. Morley, analyst. 



12 Grains of fossil ore, Clinton, N. Y. Princeton Catalog no. 6109. E. W. 

 Morley, analyst. 



11a Ferrous silicate of oolitic spherules. 

 12a Ferrous silicate of fossil grains. 



The composition calculated for the ferrous silicate in no. 11 and 

 in no. 12 is shown in no. 11a and in no. 12a. The total amount 

 of silicate in the first case is 11. 61 per cent, in the second 14.48 

 per cent. 



Compared with the composition of the silicate of no. 1, there is, 

 in 1 1 a, more silica, alumina and water, with very considerably less 

 ferrous oxide. This might be explained by regarding part of the 

 ferric oxide, all of which is treated as hematite, as being combined 

 in the silicate, bringing it closer to true thuringite. But, like other 

 explanations that might be suggested, this one does not admit of 

 proof, nor is it indicated by the limited data at hand. Doubtless, 

 the chief cause of discrepancies here, as in the other cases, lies in 

 the small amount of silicate present, with consequent multiplica- 

 tion of errors in making the calculation. 



