632 J. S. DILLER — NOTES ON THE 



between Ahmadja and Quayalar, are not important. The locality just 

 named is of especial interest from the fact that melaphyre was the first 

 rock extruded in that isolated volcanic centre, which is completely 

 surrounded by Tertiary strata ; it was followed later at the same 

 place by miea-andesite, hornblende-andesite, augite-andesite, basalt, 

 and late, if not last, by a large outpouring of liparite. 



The serpentine in the northern part of the Troad about Kara-dagh 

 has been derived from olivine-enstatite rocks of a truly eruptive 

 nature. The almost entire absence of the characteristic reticulated 

 structure in some of the serpentine from the Kemar valley leaves 

 perhaps some doubt as to the original rock from which it has been 

 derived. As previously stated, the serpentine about the summit of 

 Mount Ida has been derived from olivine-schist, which undoubtedly 

 belongs to the stratified rocks. 



Newer Series. — Although the ancient eruptive rocks are appa- 

 rently not nearly so abundant as those of more recent origin, yet 

 they represent very nearly the same range in chemical and mine- 

 ralogical composition. The granite and quartz-porphyries have 

 their modern equivalents in the liparites ; the quartz -diorites in the 

 mica- and hornblende-andesites; the augite-porphy rites in augite- 

 andesites ; the melaphyre in the basalt. However, no equivalents 

 were found for the nepheline-basalts and ancient olivine-enstatite 

 rocks. On the other hand, the syenites and their modern repre- 

 sentatives, the trachytes, which were once supposed to be abun- 

 dant in the Troad, are now known to be at most only sparingly 

 represented. 



The liparites occur in various types with many varieties, and are 

 limited to the southern part of the Troad. They appear also south 

 of Molivo on the island of Mitylene, and on the mainland at Sal 

 Mosac south-west of Aivaly. They are generally in a stony con- 

 dition, but are frequently glassy upon the boundaries, and contain 

 many fragments of the andesites which they penetrated and over- 

 flowed. They always occur in dykes, as at Cozlou-dagh, and the great 

 plateau which gives rise to the peculiar drainage of the Touzla river. 

 That some of the liparites were extruded before the deposition of the 

 " Mactra-kalk " is certain ; but from the fact that the exact age of 

 the Tertiary deposits in the southern part of the Troad has not been 

 definitely determined, the time of the extrusion of the great mass of 

 the liparites cannot be stated ; however, it occurred most likely at 

 the beginning or in the early part of the Pliocene period, when the 

 land was raised above the sea, and the islands converted into a 

 peninsula. 



The andesites embrace typical mica-andesites and hornblende- 

 andesites, as well as a great variety in which mica and hornblende 

 occur in nearly equal proportion. These, with augite-andesite, 

 occupy a great area between the Mendere and the southern coast, 

 and, unlike the liparites, they seem to have reached the surface, at 

 least in some cases, through volcanic vents. JSTot unfrequently they 

 occur in dykes also, and have evidently overflowed a large area of 

 late Tertiary deposits. 



