Ill 



faces is shown in fig. 3. Tlie form /^{601} which has not 

 been fonnd before in thomsonite is determined bv^) 



Average y . .. Number of Calculated 



value ' measurements value 



/•:« = (601):(100) = 9°12' 8°45'— 9°53' 4 9°20' 



The faces of the crystals are generally dull and coated over 

 by a brownish film ; occasionally they are quite bright. 

 2) From the hot spring a specimen was obtained which seemed 

 to be an incrustation, without any of the rock. This con- 

 sisted mainly of stilbite crystals, interspersed with a number 

 of small, spherical bodies formed probably of thomsonite. 

 The surface is rough and striated, without distinct crystals. 

 Colour, a brownish white. 



Turner Ö. Among larger masses of columnar scolecite 

 are found a few, small (up to 1 cm.) radiating masses of thom- 

 sonite. In one cavity there occurred small (1 — 2™™) projecting 

 crystals in the form of very thin plates, the faces of which 

 could not be more closely determined. 



The north coast of Gaase fjord in Scoresby Sund. 

 Here thomsonite is found in very large quantities and is, with 

 the exception of chabazite, the most common zeolite obtained 

 from the isolated basalt blocks in the moraine, it is found in 

 two somewhat different forms: 



1) In a reddish-coloured basalt, all the walls of the cavities 

 were found to be lined with a crust of thomsonite about 

 1°^ thick. The internal surface of this crust has a well- 

 marked velvety appearance, due to some minute, closely- 

 packed crystals, the breadth of which does not exceed 

 Q-imm xhe crystals have the form of thin, rectangular 

 plates and are very regularly developed , but the marginal 



'i Here, as elsewhere in this paper, the value of angles is calculated 

 according to the axial ratios given by Dana (System of Mineralogy 

 1892) unless other^wise stated. 



