MAKE A MEME
View Large Image
| View Original: | The_Quarterly_journal_of_the_Geological_Society_of_London_(12893688443).jpg (1220x2042) | |||
| Download: | Original | Medium | Small | Thumb |
| Courtesy of: | commons.wikimedia.org | More Like This | ||
| Keywords: The Quarterly journal of the Geological Society of London (12893688443).jpg Yol 53 GEOLOGY OP PART OF THE NUBIAN DESERT <br> 363 <br> places is abundant the water of the Nubian Desert is directly <br> dependent on the rainfall This is irregular and may not occur for <br> several years during which time the wells become very low and their <br> water strongly saline 1 The sources of supply in this Nubian Desert <br> are two ” firstly from wells Bir and secondly from reservoirs <br> Makhzan <br> The first of these are sunk to a depth of from 8 to 20 feet in the <br> detritus of the valleys and are fed by the water which percolates <br> into them from the neighbouring rocks being full after heavy rain <br> and diminishing as the drought continues As a consequence nearly <br> all these wells contain a considerable amount of mineral matter <br> in solution and the waters of some are almost undrinkable <br> Rounded boulders in pot-hole reservoir of Wadi On <br> Jebel Raft <br> Risha <br> Height represented in figure about 20 feet <br> The second source of supply the rainwater-reservoirs are deep <br> holes in the gullies and ravines which intersect the crystalline hills ; <br> these are filled by rainstorms and as they are partly screened from <br> the sun by the steep side of the ravine they often retain the water <br> for nearly a year Some of these in Jebel Raft are of considerable <br> size that in the Wadi Om Risha being 33 x 44 x 20 feet in cubical <br> capacity The origin of these deep holes worn in the ravines must <br> be attributed to water-action and in the reservoir of Medina in <br> Jebel Raft lie the rounded stones which have assisted in forming this <br> pot-hole See the accompanying figure It is hardly conceivable <br> that this has been effected by the rare though often violent rain- <br> storms of the present time and it must I think be attributed to <br> an earlier period when the rainfall was heavier and carved out the <br> ravines and valleys which we see at this day Similar rainwater- <br> reservoirs occur in the hills on the western coast of the Red Sea <br> 1 Within the last few years the only rains capable of filling all the wells in <br> the neighbourhood of Murrat fell in November 1891 and August 1896 In <br> this long interval only a few showers fell 36029172 111130 51125 Page 363 Text 53 http //www biodiversitylibrary org/page/36029172 1897 Geological Society of London Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 53 1897 Geology Periodicals Smithsonian Libraries bhl page 36029172 dc identifier http //biodiversitylibrary org/page/36029172 smithsonian libraries Information field Flickr posted date ISOdate 2014-03-03 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/12893688443 2015-08-26 17 52 42 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1897 Photos uploaded from Flickr by Fæ using a script | ||||
.jpg){kind=link}
