PROCEEDINGS 



OF THE 



GEOLOGICAL SOCIETY OF LONDON 



SESSION 1917-18. 



November 7th, 1917. 



Dr. Alfeed Haekee, F.R.S., President, 

 in the Chair. 



The List of Donations to the Library was read. 



A Lecture on * The Nimrud Crater in Turkish Armenia* 

 was delivered by Felix Oswald, B.A., D.ISc., F.G.S, 



The Nimrud volcano, one of the largest volcanic craters in the 

 world, is situated on the western shore of Lake Van, and was 

 surveyed and investigated geologically for the first time by the 

 speaker in 1898. The western half of the crater is occupied by a 

 deep lake of fresh water, while the eastern half is composed of 

 recent augite-rhyolites, partly cloaked in white volcanic ash. The 

 crater- wall is highest on the north (9903 feet), rising in abrupt 

 precipices over 2000 feet above the lake ( 76-Y3 feet). The southern 

 wall is also precipitous, but only reaches the height of 9434 feet 

 (the south-eastern part). A large slice of the crater- wall has 

 slipped down on "the south-west, so as to form a narrow shelf, 

 800 feet above the lake. The crater is nearly circular, 840o yards 

 from west-south-west to east-north-east, while the transverse axis 

 is 790'"3 yards. The lowest points lie on the long axis, reaching 

 only 8139 feet on the western, and 8148 feet on the eastern rim. 



The crater-wall has an external slope of 33° on the south and 

 east, where it consists exclusively of overlapping lenticular flows of 

 augite-rlvyolite and obsidian. On the south-west, west, north-west, 

 and north these are capped by thin sheets of eindery basalt which 

 must have possessed great fluidity, extending for many miles to 

 form wide fertile plains of gentle slope down to Lake Van on the 

 east and into the Plain of Mush on the west. These basalt-Hows 



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