41. Many ancient rhyolitic quartz-porphyries show on their weathered surfaces numerous globular projections. 42. The Mugga Mugga Porphyry is a lava flow. 43. Parts of the feldspar porphyry are hydrothermally altered. 44. Porphyry was rare and reserved for imperial use.45. The Lobster Creek Volcanics is actually an intrusion of plagioclase pyroxene hornblende porphyry from. 46. The contact relationships with the Johnson Granite Porphyry are on the other hand sharp. 47. All but one of the stones are Silurian rock; the other being Porphyry . 48. He later became president of the Porphyry Paving Company and had extensive land holdings. 49. Phyllic alteration typically forms in the base-metal zone of a porphyry system. 50. A lightly rusticated porphyry base supports painted brick walls with many square headed windows.
