Page:Philosophical Transactions - Volume 145.djvu/145

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129
MR. HORNER ON THE ALLUVIAL LAND OF EGYPT.

MR. HORNER ON THE ALLUVIAL LAND OF EGYPT. 129 magnifierany quartz crystals with their faces entire, nor any scales of mica. As it effervescesbrisklywith acid, the white particles are probablycarbonateof lime. From the apex of the Delta, on the left bank of the Rosetta branch, behind the dyke, at a depth of 16 feet 4 inches from the surface. Silica....,,.. .. ... ... 71176 Alumina .......1. ". ... 10 40 Sesquioxide of iron. 7*81 Carbonate of lime .................... 6-77 Magnesia .o . .. .. ... 0176 Organic matter............ -o ....... 2-50 100,00 K.-Sand very similar to I, but more exclusively quartzose and with a few scales of mica, with some hard concretions of sand. Fiom the right bank of the Damietta branch, at a depth of 31 feet from the surface. Silica.....* ...55...*.. ...............+.......... 8531 Sesquioxide of iron.. 5*98 Sesquioxide of alumina .......2. .. ... ... 172 Alumina. ......... 1-04 Carbonate of lime ............, ., 3-64 Organic matter . ..2....O.... . ,, 231 100-00 L.-Brown quartzose sand, very similar to K. Taken from the surface, near the river, at the time of low water, on the left bank of the Rosetta branch. Silica.. I ,.. 83'21 Sesquioxide of iron.., 6i01 Sesquioxide of alumina ................. 4'09 Carbonate of lime. 472 Organic matter ..............,., 1.97 100-00 M.-A light brown sand, consisting almost exclusively of transparentquartz with a few minute brown and green particles interspersed, effervescing slightly with acid. From the same locality as L, but from a depth of 67 feet 3 inches from the surface. Silica ......... 96-93 Sesquioxide of iron. 205 Sesquioxide of alumina .......... 1-02 Lime..................... . ..... ...... trace 100-00 It will be seen that the two specitnens of the present superficialNileniud, B and C, taken from localities widely apart, although consisting of nearly the same ingre- dients, differ considerably in the proportions. But in a deposit of this mechanical nature, it is probable that no two specimens, although taken from localities near to MDC CLV. T