Northern and Central Turkey. 61 



reconcile themselves to the idea of porphyry of the age of the 

 more recent chalk, or even of the oldest tertiary period. Be- 

 sides, many geologists consider as trachytes all porphyries with 

 crystals of glassy felspar ; now these crystals occur pretty often 

 in my porphyries, but I saw none in my decomposed varieties. 

 The sienitic porphyry in dykes among the slaty primary (tran- 

 sition) rocks of the Bannat also contains crystals of glassy fel- 

 spar. It is to be hoped that competent judges may soon travel 

 over South Eastern Europe, where trachytes as well as sienitic 

 porphyries occur, and they will soon agree with Beudant and 

 myself in thinking that Montdor, the Cantal, the whole of 

 Italy, the Alps, and the lowest portions of the Rhine, present 

 no porphyritic rocks like those which I have -mentioned as oc- 

 curring in Turkey, and which I regard as somewhat older than 

 the trachytes. 



On the other hand, to determine the exact limits of both de- 

 posits, would be in most cases, I think, extremely difficult, if 

 not as impossible as to distinguish exactly among a heap of 

 lavas. The trachyte has flowed more frequently as coulees. 

 Sienitic porphyry has never yet been seen overlying tertiary 

 rocks ; it only occurs in the form of dykes or hiUs among pri- 

 mary (transition) or crystalline slates. 



The trachytic rocks occupy much space in Turkey. The 

 first time we met with these was at Novibazar, in the conical 

 hill on which stand the remains of the Church of Stupani St 

 Georg (the columns of St George). This trachyte, together 

 with some trachytic breccia, extends to the north, and may pos- 

 sibly be in some way connected with a vast deposit of the same 

 kind, which lies between Rudnitza on the Ibar, and Ratschka on 

 the road to Novibazar. The southern part of the Uschize dis- 

 trict in Servia is of the same nature. On the road to Novibazar, 

 the trachytic conglomerates present many varieties containing 

 mica and hornblende : they succeed to the compact sienitic por- 

 phyries of the Ibar, and occupy much space in that triangular 

 part of country to the south of the confluence of the Ibar and 

 Ratschka. 



In crossing between Magoritsch and Strazin in Upper Mace- 

 donia, we found an immense range of trachytic hills, Avith a vast 

 quantity of all kinds of felspathic tertiary conglomerates. The 

 hills with their table-shaped summits shew, from a great dis- 



