So 



Minnesota Academy of Science 



Fig. 10. — Characteristic Surface of Jaspilyte.. .Soudan. 



stratified jaspilyte was also derived from chemical deposition. 

 Whatever may have been the physical conditions that obtained when 

 the silica of the primary masses was deposited it is plain that that 

 which forms layers interstratified with fragmental material, was 

 chemically precipitated from solution in the bottom of the ocean 

 in which the sediments were accumulated. These fragmental sedi- 

 ments are not always simply green schist, but also may be darker 

 and more slaty strata, and may even grade into various kinds of 



