Professor T. G. Bonney — On Bocks from Ararat. 55 



as amblystegite, and a green non-pleocbroic augite instead of the 

 fairly pleoclaroic (brownish-green) hornblende. 



The specimen from the Takjaltu, a parasitic cone on the south- 

 east slope of Ararat, must have come from the main pyramid not 

 very far from Mr. Lynch's line of ascent. It is "a pale grey 

 compact porphyritic rock, with plagioclastic felspar and a little 

 sanidine, glass enclosures being frequent, sometimes forming a kind 

 of network. A pale green, almost colourless augite is rather rare, 

 with remnants of a strongly pleochroic hornblende (a pale yellow, 

 h red - brown, c brown - red) and a pale green, almost colourless 

 bronzite more abundant than either." ^ 



A specimen from the south-east side of Little Ararat is a porous 

 bronzite-augite andesite, in which Dr. Becke recognises oligoclase or 

 andesine, rich in glass inclusions, magnetite, a green augite, and 

 ' bronzite ' in long thin prisms up to *06 inch. 



Chasm of Arguri [Great Ararat). 



Three are labelled as " typical stones." Two of these (C) are 

 yellowish-brown fragments, obviously rotten lava. The third (D) 

 is a compact darkish-grey rock, speckled with lightish-grey. 

 A slice of this exhibits only varietal differences from some of those 

 already described ; the base is nearly that of the specimen A. There 

 are crystals of felspar and of pyroxene as before, though the former 

 are not quite so large as usual. 



Of the other rocks (E) from Arguri, three appear to be con- 

 solidated andesitic ash or fine breccia ; three are lavas in a very 

 decomposed condition ; one is a slightly porous reddish rock, with 

 small crystals of glassy felspai-, probably allied to some of the 

 varieties already described ; and another is a similar rock of a more 

 glassy aspect and deeper red colour, both the felspars and the glass 

 intervals being slightly larger. A slice from the last shows the 

 actual glass to be fairly clear, but it is studded with very minute, 

 slightly brown microliths, and contains a large number of rodlets of 

 iron-oxide. It exhibits a fluxional structure. The porphyritic 

 minerals call for no special remark except that the rock is rather 

 deficient in pyroxenic constituents. 



Little Ararat. 



Two rocks 2 (F), one evidently a grey andesite similar to those 

 already described, the other pinker in tint, probably much the same 

 kind but rather decomposed ; it may be this rock which gives the 

 peak its dominant violet hue. Microscopic examination shows the 

 former to be a pyroxene-andesite with only insignificant varietal 

 differences from the grey rocks already described. Pyroxene is not 

 very abundant, but among it is augite, perhaps also amblystegite. 



A third specimen (G) is a rock of generally similar structure, but 

 of more brick-red colour. (It is stated to give a pinker tinge to 

 some parts of the peak.) This exhibits some slight differences under 



1 A condensed translation of the original description. 

 * Said to be typical of the dominant rock of the peak. 



