192 



I. No. 



ox THE ECLOGITES OF NORWAY 



log 



this supposition : its lime content which is higher tiian that met with in the 

 average garnets of the amphibolites. But this is not sufficient evidence, and 

 there is none more positive. Thus this question must be left unanswered. 

 One thing is certain : The existence of the garnet in this amphibolitic 

 rock depends upon the iron-prevalence in the rock, a feature common in 

 all the garnet-amphibolites investigated bv me. 



Garnet-amphibolite from Suselbakke, Mysen, Smaalenene, Norway. 



The specimens of garnet-amphibolite from Suselbakke in the parish of 

 Mysen, Smaalenene, have been derived from the Archaean of Southern 

 Norway. It is labeled "amphibolite in granite-schist", from which it appears 

 that it ma}' haxe been a mixed rock where lenses of amphibolite are inr 

 eluded in granites. With the naked eye can be discerned a decimillimeter- 

 grained ground-mass with visible black prisms of hornblende and grains of 

 teldspar. In this mass are embedded grains of red garnet, from one to 

 two millimeters in diameter. From the rock the garnet was separated bv 

 a single treatment with Clerici's solution and analyzed by the writer with 

 the followine: result: 



Sp. 



3-94- 



RO : R,03 : SiO, = 3.26 : i : 3.58 



I TiO, has not been accounted for, as it certainly has been 

 derived from inclusions of ilmenite.) 



Composition Fe-^Mn^Mg^^Caj^. 



The sample contained some ilmenite and quartz. The figure for Fe 

 is therefore too high, but there is no doubt that iron is largely preponde- 

 rant in this garnet. 



The granular ground-mass is mainly composed of brown hornblende 

 and labradorite, besides smaller amounts of titanite and iron ore. 



