. The Vermilion iron-bearing district of Minnesota : with an atlas . A. ELLIPSOIDAL PARTING IN J?. ELLIPSOIDALLY PARTED GREENSTONE, SHOWING SPHERULITIC DEVELOPMENT. ELY GREENSTONE. 147 relations to these ellipsoids. The smallest spherulites occupy the extremeoutside of the ellipsoids. From the outside they increase in size towardthe center, where, if the rock is there spherulitic at all, the largestspherulites are developed. Sometimes the development of the magmainto a spherulitic rock did not reach entirely to the center, which is thendeveloped as a massive dolerite of normal cha
. The Vermilion iron-bearing district of Minnesota : with an atlas . A. ELLIPSOIDAL PARTING IN J?. ELLIPSOIDALLY PARTED GREENSTONE, SHOWING SPHERULITIC DEVELOPMENT. ELY GREENSTONE. 147 relations to these ellipsoids. The smallest spherulites occupy the extremeoutside of the ellipsoids. From the outside they increase in size towardthe center, where, if the rock is there spherulitic at all, the largestspherulites are developed. Sometimes the development of the magmainto a spherulitic rock did not reach entirely to the center, which is thendeveloped as a massive dolerite of normal character. It is very noticeablethat while the spherulites occur in the very fine-grained lavas they areapparently equally common in some of the more coarsely crystalized formswhen these phases are ellipsoidal. The spherulitic and amygdaloidalstructures sometimes occur together, but most commonly they are notdeveloped in the same rock. Apparently the presence of one does notaltogether preclude the existence of the other, although it amounts verynearly to this. Thus, in passing over the jjarticular section
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectgeology, bookyear1903
