128 NEW YORK STATE MUSEUM 



packed with tiny opaque inclusions, perhaps magnetite, shows an 

 occasional pyrite crystal, and frequent irregularly bounded indi- 

 viduals of the material that we are assuming to be graphitic. At 

 the contacts with limestone inclusions, clear evidence of limestone 

 absorption is shown by the production of a zone of mingled ma- 

 terial, calcite and glass, the relative proportions of which vary 

 with distance from the contact. The glass is lighter in color and 

 no longer clear glass, but full of very tiny crystals, often spherulitic, 

 which are altogether too tiny for exact determination, but which 

 appear to be feldspar. The addition of lime to the melt seems 

 to have lowered the temperature of solidification sujfihciently to 

 permit at least the beginning of feldspar crystallization, while else- 

 where the material solidified as glass. This intermediate zone is 

 unquestionably one produced by direct solvent attack of the lava 

 upon the limestone, and is thus corroborative of the evidence of 

 this attack previously given. 



The amygdules in the glass have the appearance of small, round, 

 black bodies, when whole; when broken across, the interior filling 

 is light colored but dull looking and not so white as in the case 

 of the amygdules in the balls. The filling is the same in both 

 cases, either wholly calcite, or else calcite with some quartz, both 

 of fairly coarse grain. 



Chemical composition. Since the rock from the centers of the 

 large lava balls seemed in quite fresh and unaltered condition, 

 except for the olivine, it was confidently expected that a chemical 

 analysis would definitely show the composition of the lava, and 

 would be attended by no especial difficulty. But analysis devel- 

 oped the presence of a considerable amount of carbon in the rock, 

 rendering determination of ferrous iron very difficult, and showed 

 also the presence of a large quantity of water. This also was 

 difficult of exact determination. But Professor Morley has labored 

 indefatigably at the problem. The ferrous iron was finally deter- 

 mined by bichromate titration. Professor Morley states that the 

 results can not be vouched for to the single drop, as with perman- 

 ganate, but that the uncertainty is not great; that he can not hope 

 that the accuracy of the three determinations, FcsOg, FeO and 

 H2O+ is as great as that of the others but that he has every reason 

 to believe in their reasonable accuracy. Our indebtedness to him 

 for the painstaking labor and the eventual very satisfactory result 

 is most emphatically expressed. 



