( 4()() ) 



irregular transverse cracking. From the feldspar-microlites they arc 

 distinguished by the strong refraction, from apatite (occurring as 

 inclusion in the plagioclase-phenocrysts) by their behaviour when 

 tested il by means of a ' 4 / mica plate in parallel polarized light, 

 from (he very few dichroitic, green, sometimes parallel to a ilOO) 

 twinned hornblende-prisms of the second generation, mixed up with 

 them, by the very Light colour, the weak double refraction and the 

 right extinction. 



The grounds <>n which the presence of bronzite, and not of enstatite 

 or hypersthene is assumed, will further be explained. We can eon- 

 chide the microscopic description by mentioning the occurrence of 

 extremely fine undefinable microlites whh a strong double refraction, 

 whose length is only a few pp, the width by estimate no more 

 than 0.1 p. 



The chemical analysis yielded the following values, from which 

 is calculated the norm of the rock according to Cross, [ddings, 



PlRSSON and W \MIINOTu\ |. 



') Loss of ignition 5.11 n /, 



') Quantitative classification of Igneous Rooks ; Chicago, 1903. 



