Forelesninger holdt ved Advanced Study Institute of Feldspar - Oslo 1962
Lectures held at Advanced Study Institute of Feldspar - Oslo 1962

This paper presents data derived from the measurement of order-disorder relationships in plagioclase feldspars from a typical epizone magmatic province. The specimens for this examination were collected from the White Mountain and New Hampshire magma series occurring in New Hampshire. This area has been studied in detail by Billings (1928, 1945), Chapman and Williams (1935), Kingsley (1931), Williams and Billings (1938), La Freniere (1957), and many others. However, none of these studies investigated the order-disorder relationships of plagioclase feldspars. The writers believed that the approach outlined in Part I of this paper could be applied to such a well known area to provide additional information about these magma series and also test the versatility and reliability of the ordering index method.