Plate XXIV— JASPILITE. 



This rock is Irom the Grand Rapids mine, Negauuet- (Atlas Sheet XXVIII). The dark bands are 

 mainly hematite. The brown bands consist mainly of minute grains of quartz, but each grlin 

 is stained with hematite. The red jasper belts do not contiuue indefinitely, but layers die out 

 after extending a greater or less distance, with oval terminations. This is beautifully shown in 

 one of the hands. The rock illustrated by this plate is allied to that of fig. 3, PI. XIX. In the 

 change from the original rock there was almost complete oxidation of the siderite, little or no 

 hydration of iron oxide, and but little of the iron oxide united with silica to form griinerite. In 

 the rock of Hg. 2 no griineiite is present, but some occurs iu the upper part of fi.' 1 

 354 " 



