Annual report of the United States Geological Survey to the Secretary of the Interior . A. GRANULITE, NO. 998, SHOWING GRANULITIC STRUCTURE AND MICROPEGMATITE. B. BENT AND FRACTURED FELDSPAR IN PRE-CRETACEOUS TUFF. PLATE XL. PLATE XL. A. Pegmatoid intergrowth of tourmaline and quartz, No. 928 S. N. Without the analyzer, x 20. This rock formed part of a pegmatite dike inquartz-pyroxene-diorite southeast of Souora. B. Granite, No. 39 S. N., showing the large idiomorphic titanites with prongs on the sides of the largest prism. Without the analyzer, X hornblende; M = black mica; F=iron oxide
Annual report of the United States Geological Survey to the Secretary of the Interior . A. GRANULITE, NO. 998, SHOWING GRANULITIC STRUCTURE AND MICROPEGMATITE. B. BENT AND FRACTURED FELDSPAR IN PRE-CRETACEOUS TUFF. PLATE XL. PLATE XL. A. Pegmatoid intergrowth of tourmaline and quartz, No. 928 S. N. Without the analyzer, x 20. This rock formed part of a pegmatite dike inquartz-pyroxene-diorite southeast of Souora. B. Granite, No. 39 S. N., showing the large idiomorphic titanites with prongs on the sides of the largest prism. Without the analyzer, X hornblende; M = black mica; F=iron oxide; D = U. S. GEOLOGICAL SURVEY SEVENTEENTH ANNUAL REPORT PART I PL. XL. A. PEGMATOID INTERGROWTH OF TOURMALINE AND QUARTZ, NO. 928 S. N B. GRANITE, NO 39 S N., WITH IDIOMORPHIC TlTANITE AND HORNBLENDE PLATE XLI. PLATE XLI. A Granite-porphyry, No. 10S. N., showing a typical microcrystalline the analyzer,X 20. I —quartz; B = orthoclase; C — plagioclase; M =biotite. It. Spherulitic quartz-porphyry. Nh. l 17 Amador, illustrating the quartz-globulairestructure of Michel-Levy. With the analyzer, X 45. All parts of any onespherulite < xtingnish simultaneously or nearly so, or any one spherulite extin-guishes in sectors. In the photomicrograph all of the upper spherulite is extin-guished except a few faint radii. A black cross is ordinarily uot to bo
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