C P&Od££Dt$OS OF THE GEOLOGICAL SOCIETY, [vol. IxXV, 



The structure was shown to be that of a tableland bisected by a 

 great rift-valley (graben), and Hanked by a coastal plain. A section 

 was exhibited illustrating East Jordanland acting as a horst ; the 

 boundary-faults of the Jordan Trench ; the unequal sinking of 

 the contained blocks ; the western section of the tableland sunken 

 with relation to the eastern, and thrown into an asymmetric 

 anticline the limbs of which rise in steps through monoclinal flexures 

 or faults. 



Lantern-slides were used to illustrate the character of the country 

 and outstanding features in its geology, more particularly the 

 following : — the dependence of the topography upon geological 

 structure, slopes depending on the attitude of the' rocks and eleva- 

 tion upon the raising or depressing of fault-blocks or on lava-flows; 

 basins and sunken areas in the tableland; the scarps bounding the 

 Jordan Trench, especially the western fault, and fault-blocks in 

 the Trench or against its walls that have not sunk equally with 

 others ; the upturned block of Jebel Lsdum which, with the Dead- 

 Sea bottom and the block north of Jericho, indicates a median 

 fault between the boundary-faults ; the interbanding of the Jcbel- 

 Usdum salt with sandstone and shales that resemble Nubian Sand- 

 stone ; the unconformity of the Jebel-Usdum formation with the 

 Jordan lake-beds (Lisan formation) which, with the chemical com- 

 position of the salt (lack of bromine, etc.), shows that it is not a 

 Jordan lake-deposit ; high lake-terraces in the centre of the Trench, 

 with corresponding ones north of Tiberias and south in the Araba 

 Valley, showing that the Jordan lake stood 1400 feet above the 

 present Dead Sea, and that there has been no marked warping since 

 their formation ; old gravel-fllled canons of the Anion and Terka 

 Main which prove that the level of the Dead Sea before Jordan-lake 

 days stood at about its present level, and that climatic conditions 

 must have been about the same, also that it did not long precede 

 the Jordan lake ; the Lisan formation of the Jordan lake-beds, 

 thin layers of mechanical and chemical sediments veneered along 

 the Jordan river with fluviatile clays ; ' bad-land ' topography near 

 the wadis and in the Lisan formation : narrow box canons of the 

 Avadis in the Jordan Trench, and the more open valle} T s above 

 producing a sort of ' hanging valley.' 



In the main, Blanckenhorn's recent work was confirmed, in 

 particular the fault forming the western border of the Trench and 

 disturbances and sinking in the tableland ; but new points were 

 mentioned, such as the evidence of a median fault within the 

 Trench ; the sea-clift's of Lisan and Jebel-Usdum ; the wave-cut 

 shelf and the salt of Jebel Usdum ; the tilting of the Jebel-Usdum 

 block and its independence from and unconformity with the old 

 lacustrine beds ; lack of disturbance and of warping since their 

 deposition ; the age and former level of the Old Dead Sea and the 

 recent rise in the present sea. the latter indicating an increase in 

 moisture and not drier conditions as generally supposed. 



A vote of thanks was unanimously accorded to Major Brock for 

 his lecture. 



