36 Washington— -Study of the Glaucophane Schists. 



Fritsch, and later the geology, as well as the rocks, were 

 described by von Fonllon and Goldschmidt.* 



While the glaucophane schists of Syra vary considerably in 

 appearance and composition, yet, according to von Fonllon 

 and Goldschmidt, (with whose conclusions my own observa- 

 tions agree, as far as they go), they may be referred to two 

 main types, epidote-glaucophane schist and mica (quartz)-glau- 

 cophane schist. These are not divided with absolute sharp- 

 ness, as some transition forms are found, but, with only one or 

 two exceptions all my specimens may be referred to these two. 

 The more numerous divisions of Luedecke may also be put in 

 one or the other of these two groups, or regarded as transition 

 varieties. 



In association with these are found various metamorphic 

 rocks, such as gneiss and epidote schist (which are especially 

 abundant, according to von Foullon and Goldschmidt), ompha- 

 cite rocks and eclogites, and various augitic and hornblendic 

 schists. All these occur in connection with and interbedded 

 with metamorphosed limestones, but the relations of the 

 different members of the complex are far too intricate and 

 little known as yet to permit of discussion. 



Epidote- Glaucophane Schist. — It would seem that the rocks 

 belonging here are rather more abundant than those belonging 

 to the other main group. They vary from coarsely crystalline 

 forms, in which either the glaucophane or the epidote is 

 porphyritic in quite large individuals, to tine-grained varieties, 

 in which the epidote occurs as small patches in the mass of 

 dark blue, silky prismatic glaucophane, forming specimens of 

 great beauty. Garnet is present only to a small extent, and 

 mica, quartz and feldspar are not abundant in the most typical 

 representatives of this type. 



The specimen chosen for analysis is from near Kyperusa, a 

 small hamlet about 2J kilom. north of Hermoupolis, in the 

 northeastern part of the island. It is tine-grained, and shows 

 to the naked eye small prisms of pale greenish yellow epidote 

 with some white flecks of calcite and quartz, lying in a dark 

 blue, silky groundmass of minute glaucophane needles. Under 

 the microscope all these minerals are seen, the glaucophane 

 highly pleochroic, the epidote nearly colorless, together with 

 some chlorite (which is apparently derived in great part from 

 the glaucophane), a few small titanite and rutile crystals, and 

 a little feldspar, which, with the quartz and calcite, is 

 interstitial. 



*vou Foullon and Goldschmidt, Jahrb. k. k. Geol. Reichsanst, vol. xxxvii, p. 

 1, 1887. 



