Measured Calculated 



70° 5. У 



70° 55V2' 



83° 



82° 59' 



44° 37' 



44° 45' 



7Г51' 



71° 57' 



86° 50' 



86° 42' 



78° 2' 



78° 2' 



43° 13' 



43° 20' • 



30° 58' 



31° 2' 



62° 7' 



62° 4' 



58° 57' 



58° 58' 



28° 58' 



29° 



60 



s : с = (552) : (OOl) >= 



t : с = (551) : (OOl) v^ 



V : с = (334) : (uOl) v = 



z/: с = (15.5.3) : (00l)v = 



, l . с = (310) : (OOl) v = 



к : с =-- (15.5.3) : (001 )v = 



i : с = (625) : (OOl) v= 



t : Ъ = (551) : (01 0) v = 



t : t = (551) : (55T) v= 



\ t : q --= (551) : (50l) y = 



,k : q = (T5. 5. 3) : (50T)v= 



Twinning occurs rather subordinately on the eudidymite 

 from Narsarsuk. By far the greatest number of the crystals 

 are single individuals; it is only exceptionally that one meets 

 with some thin lamella grown into , or grown together with, 

 the thicker principal individual in twinned position. These 

 twins are formed according to the following rule : the twinning 

 plane = the third pinacoid (OOl); the twinning axis, about 

 which one of the individuals is revolved 180°, is at right 

 angles to the said plane. Twinning according to the second 

 of the laws proposed by Brögger^) for the Norwegian eudi- 

 dymite does not, as far as hitherto known, occur in the 

 Narsarsuk mineral. 



As has been mentioned in the foregoing, there, however, 

 occurs a remarkable intergrowth between individuals of eudidy- 

 mite and epididymite in perfect accordance with the relation 

 observed between the two minerals from Lille Arö ^). This 

 intergrowth consists in the fact that needles of epididymite are 



^) Zeitschrift für Kryst. Vol.16, p. 591. 



2) Bull, of the Geol. Inst, of Upsala. Vol. IV, pag. 23 



') Loc. cit. 



