26 Mr.W. J. Hamilton and Mr. H, E. Strickland, on the Geology of 



district derives its name, belong to a more recent epoch, and will be fully described 

 in a subsequent part of this paper ; but there are also igneous rocks of a different 

 character and older date, which require to be noticed here. They occur in the 

 northern part of the basin, from eight to sixteen miles north of Selendi, on the 

 road to Simaul (PI. III. Sec. 6), and consist of masses of trachytic rocks jutting 

 out in the bottoms of the ravines, beneath the lacustrine formation. It was before 

 stated (p. 18), that the lower portion of the lacustrine beds, in this part of the 

 basin, consists of tufaceous deposits, which are doubtless connected in their origin 

 with these trachytic eruptions. In some cases, the tufaceous beds have been 

 broken up by the igneous rock ; but in the only instance (thirteen miles north of 

 Selendi) where the superincumbent limestone was seen in contact with trap, its 

 stratification remained undisturbed ; and therefore it is probable, that these erup- 

 tions were anterior to its deposition. 



Between the ninth and tenth miles from Selendi, the tufa rests upon protruded 

 masses of decomposing syenitic trap with a nearly vertical cleavage, and half a 

 mile lower down, at the junction of two valleys, is a mass of trachytic conglomerate, 

 with a solid trappean nucleus. Igneous rocks again rise from beneath the tufa at 

 the eighth mile from Selendi, and have assumed, in consequence of decomposition, 

 a great variety of colours. 



{i.) About eight miles from Adala, on the road to Koola, is a small isolated hill 

 of grey trachyte. It rises in the vale of Lydia, at the foot of the schistose moun- 

 tains which form the north boundary of the valley of the Cogamus. A section, 

 formed by a watercourse, shows that this trachyte is older than the platform of 

 lacustrine gravel which reposes against it. 



(k.) Trachytic rocks of Smyrna. — These extensive masses of igneous matter, which 

 break up and overlie the lacustrine deposits of the Smyrna basin, are described at 

 length in a memoir specially devoted to the geology of that district. (Vol. v. pp. 

 396, 401.) 



(/.) Fouges, anc. Phocaa (lat. 38° 40'). — Igneous rocks, which have assumed a 

 great variety of character, porphyritic, trappean and trachytic, form the chief ingre- 

 dient of the hills which rise to the north of the little harbour of Fouges. They are 

 associated with, and overlaid by various beds of tufaceous and pumiceous sands, 

 which have sometimes assumed the hard, semi- vitrified character of the trachytic 

 rocks themselves, and from which they can be scarcely distinguished. These beds 

 all dip towards the south, and sometimes contain numerous cavities, which are 

 either filled or coated with mammellary concretions of chalcedony, 



(m.) Ritri, anc. Erythra (lat. 38° 18'). — The Acropolis of Erythrae is situated upon 

 an itisulated peak of red trachyte, which rises abruptly to the height of two or three 

 hundred feet, and although perfectly crystalline like that in the neighbourhood of 



