GEOLOGY OF THE TROAD. 633 



Their extrusion along the western coast began before the deposition 

 of the " Mactra-kalk ;" and along the southern coast during the 

 formation of the freshwater deposits of that region. Pyroxene 

 is generally a prominent constituent of the andesites, and frequently 

 both rhombic and monoclinic pyroxenes occur together. The former 

 is generally the most abundant, and has, in one case, been proved 

 to be hypersthene. It occurs not only in mica-andesite, as at Assos 

 and Smyrna, but also in the hornblende-andesite north-west of 

 Cozlou-dagh and the augite-andesite west of Sivriji-bournon. 

 Among the great variety of andesites may be mentioned the oldest 

 which flowed from the volcanic crater at Assos. It is a mica-andesite, 

 in the ground-mass of which is a large proportion of apparently 

 primary mica and haematite. 



The basalts occur in dykes, and, although widely distributed, do not 

 occupy large areas. Along the southern coast of the Troad the 

 basalt is of an andesitic type, and the olivine is occasionally altered 

 to distinctly cleavable pleochroitic serpentine. 



The same phenomenon is better developed in the t} T pical nepheline- 

 basalt, which forms the prominent hill of Quaralyly or Sapandja-tepe 

 near the centre of the Troadic peninsula. The basalts and nepheline- 

 basalts are evidently younger than the Tertiary deposits with which 

 they are associated ; but the time of their extrusion with reference to 

 that of the other eruptive rocks of the Troad cannot be definitely 

 determined. 



Appendix ly W. Toplet, Esq., F.G.S., Geological Survey of England 



and Wales. 



The foregoing paper is a brief notice of the main results arrived at 

 by Mr. Diller when attached as geologist to the United States Assos 

 Expedition. The field-work extended through two summers, and 

 was supplemented by researches in the petrological laboratory of 

 Heidelberg. , A MS. draft of Mr. Diller' s geological map (scale 

 1 : 100,000) was sent to me for the service of the new Geological 

 Map of Europe (and its borders) which is now being prepared by a 

 Committee of the International Geological Congress. The map here 

 given is a reduction of this map ; but some of the igneous rocks are 

 grouped, and some other details are necessarily omitted. The 

 heights are inserted from various sources — the English Admiralty 

 Charts, the Austrian Military map, and others. 



The map has been prepared in England, and Mr. Diller has not 

 seen a proof ; he is therefore not responsible for errors or imperfec- 

 tions therein. 



The Assos Expedition was sent out by the Archaeological Institute 

 of America, and was under the direction of Mr. J. T. Clarke. The 

 archaeological work was mainly confined to Assos, on the southern 

 coast of the Troad, and hence Mr. Diller's work is more complete 

 there than elsewhere. Preliminary Reports have already been 



