56 



and the acute bisectrix parallel to the c-axis. The axial ratios 

 then become a:b:c =-- 0,9985:1:1.09 or, if the c-axis is 

 shortened to Vs of its length: 



а:Ъ:с = 0,9985 : 1 : 0.726. 

 This certainly approximates somewhat to the axial ratio found 

 for weybyeite; yet the difference is considerable. 



As to the chemical composition of the two minerals a 

 certain agreement probably exists. However, the composition 

 of the weybyeite is so imperfectly known, owing to the insuf- 

 ficient quantity of material for analysis, that a detailed com- 

 parison is impossible. 



The larger and best developed ancylite crystals have been 

 found only at the locality No. 5 on Narsarsuk. The mineral 

 was met with here together with needle-shaped ægirine crystals 

 or hair-like ægirine individuals forming felted masses, together 

 with clear, prismatic albite crystals elongated in the direction of 

 the c-axis, dark-brown zircon crystals of type li, etc. Of these 

 minerals, the ancylite has been last formed. The minute ancylite 

 crystals grown together into crusts were found at the locality 

 No. 2. The crusts generally occur on strongly corroded feldspar 

 individuals. Among the numerous secondary minerals occurring 

 in the place cordylite is the only one that may be said to 

 have been found as directly associated with ancylite. The latter 

 seems to be the older of the two. 



12. Eudidymite. 



Eudidymite from Narsarsuk is of extreme rarity , as only 

 three detached crystals of the mineral have been found. They 

 were met with among the loose gravel at the locality No. 3. 

 The largest one is 32""" in length, 20™" in breadth and 11°"° 

 in thickness and consists of a large number of crystal tables 

 grown together in such a manner that the i-axes of the different 

 individuals are parallel to one another, while the respective a- 



