GEOLOGY OF THE TROAD. 635 



A few brief geological notes on the Troad are given by Dr. E. D, 

 Clarke *, Professor of Mineralogy at Cambridge ; but the first 

 systematic account of the geology is that by Philip Barker Webb, in 



1821 f. 



Lieut, (now Admiral) T. A. B. Spratt, when surveying the northern 

 Troad for the Admiralty, in 1840, with Comm. Graves, produced a 

 topographical map which has not yet been superseded. His purely 

 geological notes on the country were not published till 1857$ ; but 

 an account of his researches on the physical features of the country 

 was given by Dr. P. W. Forchhammer in 1843 §. 



TchihatchefFs great work on Asia Minor |j describes the rocks of 

 the Troad in detail ; but much has been done since then in the 

 study of petrology, and the rocks therein described and marked as 

 " Trachytes " must now be referred to several different classes ^[. 

 The same, no doubt, holds true of other districts in Asia Minor. 

 Mr. Diller, in a letter to me, says : — " In the vicinity of Smyrna the 

 rocks formerly marked trachytes should now be marked andesites ; 

 and it seems probable, from the hundreds of specimens I have ex- 

 amined microscopically from the Levant, that the trachytes properly 

 so called are scarce in that country." 



The Tertiary beds have been studied by Calvert and Neumayr, 

 who describe several new species of Unio, Melania, Melanopsis, &c. 

 from Eenkioi (Arenkioi) on the shores of the Hellespont **. 



Amongst the more recent publications, besides those previously 

 mentioned, the following are important. E. Yirchow ft describes 



* ' Travels in various countries of Europe, Asia, and Africa.' 6 vols. 4to. 

 London. Troad in vol. ii., chaps, iv.-vi., 1812. 



t ' Osservazioni intorno alio stato antico e presente dell' Agro Trojano.' 

 Biblioteca Italian a, Milan, 1821, pp. 112 and map. Although, as is stated in 

 the title, this memoir is written by a " gentiluomo Inglese," no English transla- 

 tion has appeared. It is best known from the French edition : — " Topographic 

 de la Troade ancienne et moderne." Paris, 1844. It has also appeared in 

 German. A copy of the original, in Italian, is in the library of this Society. 



\ " On the Freshwater Deposits of the Levant," Quart. Journ. Geol. Soc. 

 vol. xiv. pp. 212-219 : this paper refers chiefly to the Troad. 



§ Journ. E. Geograph. Soc. vol. xii. p. 28 ; see also ' Topographische und 

 physiographische Besehreibung der Ebene von Troia,' mit einer Karte von 

 T. A. B. Spratt. 8vo. Frankfort: 1850. 



|| ' Asie Mineure,' 4 vols. 8vo. Paris. The Physical Geography was published 

 in 1853 ; the Paiseontology (by D'Archiac, Fischer, and De Verneuil) in 1866 ; 

 the Geology in 1867-69. The Geological Map is on the scale of 1 : 2,000,000. 



% The andesite of Assos (the Second Trachyte of Mr. Diller's Assos Report) 

 is the famous "Sarcophagus-stone," which was believed to have the power of 

 rapidly consuming all bodies buried in it. 



** " Die jungen Ablagerungen am Hellespont," Denkschr. k.-k. Akad. Wiss. 

 Bd. xl. pp. 357-378, 1880. 



For a discussion as to the correlation of the Newer Tertiaries of the Levant 

 &c. see Neumayr, " Ueber den geologischen Bau der Insel Kos und iiber die 

 Gliederung der jungtertiaren Biunenablagerungen des Archipels." (Appendix 

 by M. Homes.) Denkschr. k.-k. Akad. Wiss. Bd. xl. pp. 213-314, 1880 ; also 

 Fuchs, Verhandl. k.-k. geol. Reichsanst., 1881, p. 173. 



ft " Reise nach Troja," Verhandl. Berlin Gesellsch. Anthrop. 1879, pp. 204- 

 216 ; and " Beitrage zur Landeskunde der Troas," Abhandl. k. Akad. Wiss. 

 Berlin, 1879. 



