158 Geological Society. 
appearing in smaller detached areas to the W. and N.W. Probably 
these have existed as islands from early time, and around these the 
later rocks have accumulated. Mt. Ida itself is almost a dome, the 
lowest rocks (talc schists) occupying the summit. On the northern 
slopes there is true gneiss. No igneous rocks enter into the struc- 
ture of this mountain. At different horizons there are bands of 
coarsely crystalline limestone ; and, as far as can be seen, this series is 
conformable throughout. 
(2) Eesting on these old rocks and in part made up of their 
remains is a series of partially crystalline rocks, chiefly limestone. 
It is probable that this series is in large part of Cretaceous age ; but 
it contains rocks which are older, possibly Palaeozoic. Eocene fossils 
have lately been discovered by Mr. Prank Calvert, which also may 
have come from this series. The rocks in the south of the Troad, 
hitherto supposed to be Lower Tertiary, are now known to be of 
later date. Sharply marked off from these older rocks are the 
Upper Tertiaries : these are of two ages, occurring in two distinct 
areas. 
(3) The Upper Miocene, which fringes the western shores of the 
Troad, and forms a broader band at the north-west corner in the 
lower course of the Mendere. Hissarlik is built on this. These 
beds are marine, and belong to the Sarmatian Stage. The Troad is 
the most south-westerly point at which the MactrdhalTc is yet 
known. 
(4) Freshwater beds, which occur in force in the interior of the 
country, between the Mendere and the south coast, and in patches 
near the coast. These are Upper Miocene or Lowest Pliocene. 
Later than these are the Pliocene beds of the great plain of 
Edsemet. 
The igneous rocks are of various ages ; but most are of Tertiary 
date. The oldest is a granite which intrudes through and alters the 
oldest (? Archaean) crystalline rocks. This is invaded by dykes of 
Quartz-porphyry. 
Quartz-diorite invades and alters the group of partially crystalline 
rocks. 
The oldest rocks in the newer series are the Andesites and Lipa- 
rites. These, in part, are older than the Sarmatian stage, as the 
conglomerate at its base contains fragments of these rocks. But they 
are also in part of later date. Where they can be studied together 
the Liparite is the later of the two, as it flows through and carries 
up fragments of the Andesite. The Andesite (unlike the Liparite) 
seems to have reached the surface, in some cases, through volcanic 
vents. 
Basalts and Nepheline-basalts are of lato Tertiary date ; possibly 
they are the latest volcanic rocks of the district ; but their relation 
to the other eruptive rocks of the Troad cannot be definitely deter- 
mined. 
The volcanic rocks in the isolated area between Alimadja and 
Lyalar are interesting because their relative ages are here well seen. 
The earliest was melaphyre ; this was followed by mica-andesite, 
