Some Occurrences of Piedmontite in Japan. 



By 



B. Koto, Ph. D. 



Professor of Geology, Imperial University. 



With Plate XXI. 



As has been already staterl in my other paper(0, the occurrence 

 of Manganese epidote or Piedmontite is often associated with the 

 Glaucophane-bearing rock(^) in the so-called crystalline schists-system 

 in Japan. The rock, which contains Piedmontite as an essential 

 component, is well-characterized in outward appearance by being of a 



(i) This journal, Vol. I, No. I, p. 85. 



(2) I take here the opportunity of adding a few words in way of caution on the statement of 

 Dr. K. Oebbeke in his vahiable paper, entitled : ' Ueber den Glaukophau und seine Verbreitung 

 in Gesteinen '; Zeitschrift d. deutsch, geol. Ges. XXXVIII, p. 641 aud 653. Vide also Zeitschrift 

 für Ki-ystaUographie und Mineralogie, XII, p. 285. I state it here wr&nJim : he says, 'Durch 

 Herrn Dr. Naumann, früheren Director der geologischen Landesaufnahme von Japan, erhielt ich 

 eine Suite von Gesteinen, unter denen einige von der lusel Sikok (Sikolcu) meine Aufmerk- 

 samkeit sofort erregten wegen ihrer Ähnlichkeit mit Glaukophan-Eklogiteu. Die Untersuchung 

 geigte jedoch, class in diesen Gesteinen kein typischer Glauhophan, sondern eine intensiv blaur/rün 

 gefärbte Hornblende vorhommt.' The most excellent glaucophaue occurs, however, in the same 

 rock-complex, from which Dr. Naumann had collected the 'Eklogitschiefer ' (Garnet-amphibo- 

 lite ?), aud other karinthine-beariug schists, although, I believe, they do not come in the same 

 geological horizon. I have given a short description of our glaucophane from Sikoku in my 

 paper : ' A Note on Glaucophaue.' I regret very much that tha work of Dr. Oebbeke had not come 

 to hand before the publication of mine, since otherwise I should have given a more detailed discus- 

 sion, I now feel it my duty to call the attention of those who read the paper of Dr. Oebbeke to the 

 fact, that in the island of Sikoku there are both kinds of amphiboles, the one a bluish-black, highly 

 pleochroic Hoiubleude, the other a true glaucophaue ; and the rocks in which they respectively 

 occur, i^how a marked diff irence in the characters of the associating components, such as garnet 

 etc. . Dr. Oebbeke is perfectly right in his description of a bluish-black hornblende, but what I 

 believe to be a true glaucophane is also a typic il oue, and has a striking resemblance to those 

 of Zermatt and the island of Groix, specimens of which were kindly given to me by my honoured 

 professor, Geheimenb.-rgrath Dr. Zirkel. I am of opinion, that there are many intermediate forms 

 between a hornblende of crystalline schists, and a Glaucophane, so that in some cases it may be 

 difficult to draw a sharp line between them. 



