96 



When 1 wrote the "Mineralogia Groenlandica", in 1905^, 

 I had never seen gyrolile and of the above cited works of 

 Haidinger and Heddle I knew nothing; 1 thought then, that the 

 occurrence of gyrolite in Greenland could not be considered 

 as certain, so much the more as there did not exist any ana- 

 lysis of the Greenland mineral. Subsequently Mr. Cürrie made 

 me acquainted with the above cited works and drew my atten- 

 tion to Levy's description. He also sent me specimens of gyro- 

 lite from different localities, by comparison with which I soon 

 found the mineral in specimens from several localities in the 

 Greenland collections of the Museum of Copenhagen. On a 

 closer examination of these 1 found that the mineral from 

 iViakornat showed such highly interesting crystallographical 

 and physical development, and in most respects differed so 

 much not only from every formerly known gyrolite but also 

 from almost all other zeolites, that it deserved a special 

 description. 



In the following, then, 1 shall first describe the mineral 

 from Niakornat, and afterwards that from the other Green- 

 land localities. 



In conclusion I have to pay my best thanks to Mr. J. Cürrie 

 for his kind assistance to me without which I should never have 

 come to make the following examinations. 



I. Gyrolite from Niakornat. 



Occurrence. About the occurrence we only know what 

 Giesecke, who alone of all has collected the mineral at this 

 place, states^). The rock is a basaltic breccia (tufa) in which 

 the size of the fragments varies from that of a pea to the 

 weight of several hundred pounds; they consist of basalt or 

 "Wacke" or amygdaloid, the last of which contains quarz 

 chalcedony and the "faseriger Mesotyp". Upon the specimens 



1) Medd. om Grønl. 32. 

 '■') 1. с. p. 245. 



