30 



l'KMIl r.SKOI.A. 



M.-N. Kl. 



The clKiiiic.'il composition n\' the cclogitc was now calculated with 

 the following' result: 



In the quantitative clas.sification this eclogite belongs to the subrang 

 palisadose, IV, i, 2, 2, 2. In Washington's tables there are not very many 

 analyses representing this subrang; some of them agree closely with the 

 above figures, and among them are some of abyssal as well as of volcanic 

 rocks. We may note an olivine-gabbro from Orange Grove, Baltimore 

 County, Maryland, which, according to G. H.Williams', is composed of 

 diallage, hypersthene, anorthitic plagioclase and olivine, the latter with 

 reaction rims where it is in contact with feldspar. This rock thus has 

 a nearly normative mineral composition. Other nearly identical analyses 

 represent hornblendite, a monomineralic rock of the amphibolite facies. 



The structure of this eclogite is shown in fig. i, pi. I. The garnet, 

 in the eclogite from Almklovdalen, occurs in the manner of rounded 

 phenocrysts, measuring about one cm. in diameter. They are practically 

 free from inclusions and, as H. Reusch points out, are cut by a set of 

 cracks parallel to one other in all the indi\idual crystals of a specimen. 

 In other ways the eclogite shows no parallel structure, the surrounding 

 olivine-rock, on the other hand, showing the most pronounced foliation. 



The pyroxene also occurs as phenocryst-like, rounded individuals, a 

 little smaller than the cr^'stals of garnet. All these phenocrysts are em- 

 bedded in an evenly granular millimeter-grained ground-mass composed of 

 the same kind of pyroxene as the phenocrysts. Trifling amounts of pale 

 green amphibole are found at the contacts between the garnet and the 

 pyroxene, and in still smaller quantities there occur flakes of chlorite 



1 U. S. G. S. A. R. 15, p. 674, 1895. 



