1864.] T. STERRY HUNT ON LITHOLOGY. 35 



name of melaphyre as a useless synonym, in which I agree with 

 him. (Gesteinslehre, page 48.) More recently however, Senft {Die 

 Felsarten, page 263) has endeavored to give a new signification 

 to the term, and defines melaphyre as a reddish-gray or greenish- 

 brown colored rock, passing into black, and containing neither 

 hornblende nor pyroxene. The melaphyres of Thuringia and of 

 the Hartz, according to him, consist of labradorite with iron- 

 chlorite (delessite), carbonates of iron and lime, and a considerable 

 portion of titaniferous magnetic iron. Hornblende and mica are 

 present only as rare and accidental minerals. We have already 

 alluded to this class of anorthosite rocks, as requiring a distinct- 

 ive name ; but from the historical relations of the word melaphyre, 

 it seems to be an unfortunate appellation for rocks which are not 

 black in color, and from which both hornblende and pyroxene 

 are absent. 



We now come to consider that third group of silicated rocks, in 

 which the f«ldspathides are replaced by the denser double silicates 

 of the grenatide family, garnet, epidote, zoisite, and perhaps ido- 

 crase. Red garnet enters into many gneissic rocks, and even 

 forms with a little admixture of quartz, rock -masses. In some of 

 these, as in the Laurentian series, there appears an admixture of 

 pyroxene, forming a passage into omphazite or eclogite ; which 

 consists of smaragdite (pyroxene) and red garnet, sometimes mixed 

 with mica, quartz, and kyanite, and passes through an increase of 

 the latter into disthenite or kyanite rock. An aggregate of horn- 

 blende and red garnet forms beds in the Green Mountains, and an 

 admixture of red garnet with lievrite and a little mica makes up a 

 rock in the Laurentian series. This is evidently related to euly- 

 site, a rock forming strata in gneiss in Sweden, and consisting of 

 garnet, pyroxene, and a mineral having the composition of an 

 olivine in which the greater part of the magnesia is replaced by 

 ferrous and manganous oxyds. Related to this is an apparently 

 undescribed rock from the Tyrol, of which a specimen is before me, 

 consisting of red garnet, green pyroxene, and yellowish-green 

 olivine, the latter greatly predominating ; and also a coarsely 

 crystalline rock from Central France, recently described by the 

 name of cameleonite, and composed of olivine, with pyroxene, and 

 enstatite, a magnesian augite ; these minerals being accompanied 

 by spinel, sphene, and ilmenite. I have already alluded to the true 

 euphotides, in which a compact zoisite (jade or saussurite) takes 



