228 



B. KOTO. 



coii«icler;ible area«, just as the augite behaves within the mass of 

 diabasic components. This ophitic plate of hornblende is well ex- 

 emplified in the rock from Kawa-na, near the railway station at 

 Iwanuma. The hornblende, like the biotite occurring associaled with 

 the amphibole, is variously pierced through by needles of apatite. 



The t-ranite-hornblende inmiediately in ccjntact with the dyke (^f 

 lamprophyre presents quite an anomalous feature, one de\ iating from 

 the habitus hithert«) described, tlie clianges in it having Ijceu, l)ey(jnd 

 all doubt, bnxight about by metaniorphism in c«jming in (-(jntact with 

 the intruding dyke. Here the amphibole is smaller in size tlian the 

 otlier \ariety, and moreover, occurs in rather flat prisms more bluish 

 than oreen in colour, while its cleavage-sutures are numerous and 

 distinct. Its crystals show diverse intergrow^th among themselves, a 

 phenomenon rarely obser\ed in other cases ; tlie outlines of larger 

 individuals are irregular and alh^triomorphic. In short, the Avhole 

 appearance is an exact ctjpy of that commonly met with in some 

 uranular crvstalline schists. 



O 'J 



Among the secondary minerals may be mentioned epidute in 

 s«jniewhat large grains with its customary intense pleochroism ; 

 it is found usually enclosed within a more or less Ijleached lùotite 

 or in hornblende. 



The material for the formation of epidote must have been 

 directly derived from the enchasing minerals. Feldspars, though 

 showing an advanced stage of decomposition, are free from it, indica- 

 ting that tlie feldspars in the present case are p<Jor in lime. When 

 epidote occm-s, it can only ha that the material for it has flowed to 

 that spot by capillary action through the cleavage-plane, or through 

 some fissure admitting free passage. The epidote-grains thus originated 

 are connected by strings of chhjritic materials to the mother-mineral, 

 which is, as is already stated, either biotite or hornblende. The 



