Sentence Examples

  • - Recent volcanic eruptive rocks (including rhyolite, trachyte, phonolite, andesite and basalt) have been examined at a number of points throughout both the geological regions of the island.
  • The principal quarries are in Dodge, Green Lake (a blackish granite is quarried at Utley and a pinkish rhyolite at Berlin), Marathon, Marinette, Marquette, Sauk, Waupaca and Waushara counties.
  • Quartz occurs as a primary and essential constituent of igneous rocks of acidic composition such as granite, quartz-porphyry and rhyolite, being embedded in these either as irregularly shaped masses or as porphyritic crystals.
  • In the south of the island there are sills and dykes of felsite, quartz-porphyry, rhyolite, trachyte and pitchstone.
  • Augite-andesite predominates, but basalt and rhyolite also occur.

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