276 DR. J. S. FLBTT ON ROCK-SPECIMENS FROM [Aug. I904, 



Appendix I. 



Notes oh the Collection of Rock-specimens made bij Col. English 

 in European Turkey and Asia Minoe. By John Smith Flett. 

 M.A., D.Sc, F.G.S.. 



The collection of specimens submitted to me by Col. English, though 

 not very large, included representatives of many different kinds 

 of rocks — sedimentary, igneous, and metamorphic. The most 

 numerous, however, were the recent lavas, which ranged 

 from rhyolites and trachytes to very basic augitites. Many of the 

 specimens, having been collected in the course of hurried traverses 

 through difficult regions, were not so fresh as might have been 

 desired. Yet it was possible, in nearly all cases, to form a definite 

 opinion regarding the nature of the rock and the group to which it 

 was to be assigned. 



The clastic sediments and organic limestones of the Tertiary Series 

 require no special description, but mention may be made of the 

 occurrence of red, baked, and hardened, nodular shales, 

 which had been contact-altered apparently by lava-flows that 

 covered or enveloped them. None of the advanced stages of thermal 

 alteration were found in any of the rocks sliced. Tr achy tic (?), 

 andesitic, and basaltic tuffs were numerous, but call for 

 no detailed treatment. 



The assemblage of crystalline, igneous, and metamorphic rocks 

 was on the whole very similar to that which has been described by 

 J. S. Diller from the adjacent district of the Troad. 1 "With the 

 exception of the nepheline-basalts, practically all the rocks 

 described by him were present also in Col. English's series ; and 

 there were onlv one or two classes the occurrence of which was not 

 already known from Mr. Diller's paper. 



lihyolites were certainly few, although they are reported 

 as abundant in the Troad ; only one good specimen was collected, 

 at Boz Tepe, west of Keshan. It may be remarked, however, that 

 many of the more felspathic 'andesites' were both decomposed and 

 much silicified, so that often it was uncertain whether originally 

 they might not have had the characters of rhyolites. Trachytes 

 were equally rare, in fact it was doubtful whether they were 

 represented at all. 



Most of the lavas were andesitic, and hornblende-andesites 

 preponderated, though biotite-andesites were also common. A 

 pale-green pyroxene was practically always present in these latter 

 rocks, and in some of them the biotite was so intensely corroded and 

 so inconspicuous, that a peculiar type of pyroxene-andesitc 

 was developed, in which the essential constituents were a pale- green 

 (sometimes pleochroic) augite and highly-zonal plagioclase-felspar. 

 Its abnormal character raised suspicions as to its true nature; and, 

 on further examination, it became clear that these felspathic augite- 



1 Quart. Jouru. Geol. Soc. vol. xxxix (1883) p. 627. 



