402 THE CANADIAN NATURALIST. [Dec. 



zircon, described by Prof. Ccoke, from the same region, occur in 

 veins in the horublendic granites of that locality, Small veins 

 cat'ing a scmewtat similar rock at Marblehead, contain crystal- 

 lized green epidote with white quartz and red orthoclase. 



§ 25. The veins which we have described are frequently of 

 very limited extent, and seem to occupy short and irregular fis- 

 sures, while in other cases the mineral aggregates which charac- 

 terize them occur in nests or geodes. This is seen near Fall 

 Brook in the Nerepis valley in New Brunswick, where the red 

 micaceous granite is in one part very friable, and presents irregu. 

 lar geode-like cavities, sometimes several inches in diameter, 

 which are partially filled by radiating prisms of black tourmaline, 

 accompanied with quartz and albite crystals, and more rarely 

 small octahedrons of purple fluorine. The enclosing granite is 

 composed of deep red orthoclase, with small portions of a white 

 triclinic feldspar, smoky quartz and black mica. The conditions 

 seen at this place recall the description of the ftimous locality of 

 feldsnars, etc., at Fariolo near Baveno in Northern Italy. The 

 rock described as a granite, resembles, in a specimen before me^ 

 some of the intrusive granites of New Brunswick, and contains a 

 pink and a white feldspar, with a little Hack mica. It includes 

 veins of graphic granite, and also spheroidal masses, which differ 

 in texture from the mass of the rock, and present geodes of con- 

 siderable size, lined with fine large red and white crystals of or- 

 thoclase, accompanied by albite, epidote, quartz, fluorine and a 

 greenish mica (or chlorite) all of which, according to Fouruet, 

 are so mingled and interlocked as to show that they are of contem- 

 poraneous origin. To these are to be added, as occurring in the 

 o-eodes, prehnite, calcite, hyalite, and specular iron. The ortho- 

 clase crystals often have adhering to their opposite faces crystal- 

 line plates of albite, which are larger than the planes to 

 which they are attached. The crystals of orthoclase moreover 

 frequently present hollowed-out or hopper- shaped faces, which 

 Fournet happily describes as resulting from the forming of the 

 frame-work or skeleton of the crystals, when the material was not 

 sufiicient for their completion. A process analogous to this is 

 often seen in crystallization, whether from fusion, solution or 

 vaporous condensation, giving rise in some cases to external de- 

 pressions, and in others to internal cavities in the resulting crystals. 

 Fournet ascribes the formation of th3 geodes in the granite of 

 Fariolo to a process of shrinking and a subsequent segregation 



