572 REPORT OF NATIONAL MUSEUM, 1890. 



on the Isle of Arran. Kugel porphyry is a name given by German 

 writers to varieties showing - spheroids with a radiating or concentric 

 structure. (Specimen 36235, from Baden.) Micropegmatite is the term 

 not infrequently applied to such as show under the microscope a peg- 

 matitic structure. (Specimen 70041, from Mount Desert, Maine, and 

 Fig. 2, PI. cxx.) Various popular names as leopardite and toadstone are 

 sometimes applied to such as Nos. 27587 and 35722, from near Char- 

 lotte, North Carolina, and the peculiar spherlitic form, from Newbury, 

 Massachusetts, No. 70138. 

 The following localities and varieties are represented : 



Microgranite : Friedrichsrode, Germany, 70234, 70744, and 70251; Muhlenthal, Pop- 

 penberg and Auersberg. In the Harz Mountains, Germany 36223, 36222, and 

 36224; Nassau, Saxony 36225; Norway 70250; Elfdahlen, Sweden 36232; Cata- 

 lonia, Spain, 36233; Liskeard, Wheal Busy and Penhall Moor, Cornwall, England, 

 '36228, 36229, and 36231. 



Granophyr : Kirneckthal and Barr Alsace, in the Voges Mountains, Germany, 36234 

 to 36239 inclusive; Lake Lugano (Lago di Lugano) Switzerland, 36606, 36608, 

 36609, and 36611 ; Mount Desert, Maine (micropegmatite) 70038, 70041, 70042. 



Felsoplvyr : Albany, Mount Kearsarge, Waterville, New Hampshire, 27973, 29599, 

 29591, 29601, 29605 ; Marblehead, Massachusetts, 35953, 35955, 35956,35959, 35961; 

 Nahant, Massachusetts, 69671 ; Saugus, Massachusetts, 38031 ; Newbury, Massa- 

 chusetts, 70138; Hyde Park, Massachusetts, 35942; Hiugham, Massachusetts, 

 35943 ; Charlotte, North Carolina, 35722 and. 27587 ; St. Francois, Iron and Stone 

 Counties, Missouri, 26406, 26341, 26593; Lake County, Minnesota, 26570 and. 26630; 

 Bradon, Wisconsin, 28503 ; Park County, Colorado, 68943 and 68921 ; Lake County, 

 Colorado, 68861 and 68901 ; Washoe District, Nevada, 24052 and 24071 ; St. Cath- 

 arine, Brazil, 69860 ; Cornwall, England, 36188 ; Isle of Arran, Scotland, 70375 and 

 70378 ; Freiberg, Adorf, Werdan, Grimma, Erdmansdorf, and Schoeneck, Saxony, 

 38351, 3867 to 3870, inclusive, 36227, 36248, and 73109; Dossenheim, Handschuh- 

 sheim, and Weinham, Baden, 36242, 36246, and 36255; Odenwald, Germany, 36241 

 and 36243; Jura, France, 38259, 38245, and 38254; Poeplitz, Bohemia, 34808; 

 Danemora and Elfdalen, Sweden, 36250, 36244, 36245, and 36247 ; Isle of Hogland, 

 Russia, 27550. 



Vitrox>hyr : Meissen and vicinity, Saxony, 3631, 3642, 3872, 3876 to 3880 inclusive, 4115, 

 34678, 36252, 36258, 36259; Auer and Recoaro, in the Tyrol, 36253, 38879; Lake 

 Lugano region, Switzerland, 73121 ; Isle of Arran, Scotland. 36200 and 70374. 



2. The liparites. 



Mineral composition. — These rocks may be regarded as the younger 

 equivalents of the quartz porphyries, or the volcanic equivalents of the 

 granites, having essentially the same mineral and chemical composition. 

 The prevailing feldspar is the clear glassy variety, of orthoclase known 

 as sanidin; quartz occurs in quite perfect crystal forms often more or 

 less corroded by the molten magmas, as in the porphyries, and in the 

 minute, six-sided, thin platyforms known as tridymite. The accessory 

 minerals are the same as those of the granites and quartz porphyries. 



Chemical composition. — Below is given the composition (I) nevadite, 

 from the northeastern part of Chalk Mountain, Colorado, as given by 

 Cross.* (II) That of a rhyolitic form, from the Montezuma Eange, 



* Geology and Mining Industry of Leadville, Monograph xn, U. S. Geological Sur- 

 vey, p. 349. 



