THE AROHiEAX FORMATIOX OF THE ABUKUMA PLATEAU. 209 



ment of component minernls, are, so to spenk, primary r(^ok.s, and shcMild 

 not be coiifonnded witli tlic foliated granite. The two classes of rocks 

 are quite distiiict in origin, and are riot issues from a common stock 

 of ofranite. JSTo o'eolo^-ical continuity is ever found lietween them : 

 on the contrary, the J/.uu'entian granite and f\\o. foliated granite 

 intrude into tlie oyerlying, genuine gneisses of the Takaiudvi series, 

 (lood exposures of their contact will he ire(|uentiy nu'iitioned wlien 

 ex])Iaining tlie profiles in tlie se(piel. 



We now return to tlu' ser-tion wliidi we left at ishi/uini, in 

 Gozaisho. 



UoiDg westwards for a sliort distance, we arrive at the u])])er 

 edge of the rapids, whence the Sam<;-gawa takes a narrow and swift 

 course down from tlie plareau to tlie lowland, which lies fniaher 

 to the east. Here is the boundary of the districts, Higashi-Shirakawa 

 and Kikuta. As may be clearly understood from the profile (C-D), 

 tlie al)oye mentioned (rozaisho series are brought to a sudden rlose 

 by an outcroj) of granites. The massive rocks are dome sha])('(l ; 

 the peripheral, schistose iiornblende-granite with its enclosed 

 ])atches of the titanite-amphibole schist has a schistose plane which 

 her!' dips eastwards with higli angles, but on the (^ther side has 

 westward inclinations. The luicleai- part is a young biotite-granite 

 (M (r) with mu(di quartz and less mica ; this bard rock hangs oyer 

 tlie deep gorges of the Same-gawa. 



The rock which we first meet with in coming from the east is the 

 rao-o-ed form of an old hornblende-oTanite, over which the road makes 

 many crooked turns. It is a schistose modification of that granite. 

 Examined under the microscope, it is seen to be made up of biotite, 

 hornblende, plagioclase, orthoclase and, lastly, quartz. J>iotite and 



