64 Dr Boue on the Geography and Geology of 



for two leagues to the west of Egri-Palanka, the Egridere is a 

 very small rent runnhig W, S. W. and E. N. E. ; and apparent- 

 ly of very recent formation, as no old alluvium is met with. 



I think we may consider these trachytes as immediately con- 

 nected with those around Karatova, or at least as subordinate 

 jx>rtions of that great centre of igneous action. Its northern 

 limits cannot be far from the Egridere valley ; but I was un- 

 able to determine its southern limits?, as, in order to do so, I 

 must have crossed from Dubnitza to Karatova by way of Bo- 

 bosh ; a journey of sixteen leagues, in a hilly woody country ; 

 however, I shall perhaps ascertain this some other time. Still, 

 although analogy with Hungary may point out Karatova as a 

 centre, I found to the north of Kostendil and Radomir so many 

 recent igneous eruptions, that it will also be necessary to exa- 

 mine whether they are connected with those of Egridere and 

 Karatova. Indeed, on looking from the hills about Radomir 

 towards the west, and especially tlie north-west, the eye is 

 struck by the appearance of many conical and singularly shaped 

 hills, most of which are pyrogenic, doleritic, or felspathic, and 

 only a few calcareous. Between Radomir and Gerlo I only 

 observed compact limestone and slate, with alluvium or loss ; 

 but at Gerlo there occur five doleritic cones, all in a line run- 

 ninsr N. N. W. — S. S. E. Three of these are situated to the 

 oast, and two to tbe north of Gerlo. The rock is generally a 

 basaltic dolerite with crystals of augite and sometimes of fel- 

 spar, and a tufa of the same nature, which is sometimes partly 

 amygdaloidal with occasional small veins or druses of zeolite 

 (mesotype). The most curious fact is, that these rocks have 

 made their appearance in the midst of tertiary sandstones and 

 snarls, which they have upraised, so that they now incline to the 

 N. E. at an angle of 45°. This is clearly seen in the small 

 hollows east of Gerlo, where we find the highly inclined junc- 

 tion of the doleritic tufa with the indurated and altered tertiary 

 sandstone and marls. The tufa even appears in some cases to 

 be intei-posed as a kind of salbande, or aggregate of the debris 

 of the rocks cut through by the dolerite ; in short, it lies be- 

 tween the dolerite and the sandstone. Above the tufa we find 

 distinct alternations of marl and sandstone, and marl and ter- 

 tiary limestone with oysters, encrinites, echinites, bivalves, and 



