210 GRANITES AND GRANITIC VEIN-STONES. [XI. 



who looked upon them as having been formed by igneous 

 injection. 



38. The principal mineral species known in the correspond- 

 ing vein-stones of the Laurentian rocks of North America are 

 the following : calcite, dolomite, fluorite, apatite, serpentine, 

 chrysolite, ckondrodite, wollastonite, hornblende, pyroxene, pyral- 

 lolite, gieseckite, scapolite, petalite, orthoclase, oligoclase, albite, 

 muscovite, phlogopite, seybertite, tourmaline, garnet, idocrase, epi- 

 dote, allanite, zircon, spinel, chrysoberyl, corundum, quartz, 

 splwne, rutile, menaccanite, magnetite, hematite, pyrite, and 

 graphite. To which may be added some rarer species, such as 

 tephroite, willemite, franklinite, zincite, warwickite, found in a 

 few localities only, and others of less importance. Of the 

 above list, those species whose names are in italics have been 

 recognized as constituent minerals in the stratified rocks in 

 which the veins occur. 



The most important species in these vein-stones are calcite, 

 quartz, orthoclase, phlogopite, pyroxene, apatite, and graphite, 

 of which some one or more will generally be found to prevail 

 in the veins in- question. The greater part of the species named 

 in the first list were observed by Daubr6e in the veins near 

 Arendal, and to these he adds axinite, gadolinite, and more 

 rarely beryl and leucite ; * while in the island of Utoe, asso- 

 ciated with iron-ores, crystalline limestones, and hornblendic 

 rocks passing into gneiss, are similar granitic vein-stones con- 

 taining orthoclase and quartz, with tourmaline, cassiteritc, and, 

 in the middle of the veins, petalite, spodumene, and lepidolite. 

 This association is the more worthy of notice, as the only otl un- 

 known locality of petalite (if we except the castor of Elba) is 

 in the crystalline limestone of Bolton, Massachusetts, where it 

 occurs, probably in a vein-stone, with scapolite, hornblende, 

 pyroxene, chrysolite, spinel, apatite, and sphene. 



Fora notice of the occurrence of leucite in these veins, and also in veins in 

 Mexico, see the author's Contributions to Lithology (Araer. Journal Science, 

 (2), XXXVII. 264). According to Garrigou, this rare species occurs both well 

 crystallized and in compact porphyroid masses, in dioritic rocks (ophites), at 

 Lusb6 in the valley of Aspe, in the Pyrennees. (Bull. Soc. Geol. de Fr. (2), 

 XXV. 727.) 



