- l/i9 — 
at a depth greater than 5o centimetres. At a depth of 5 metres, there were only 
traces of salt 11. The following tahle (taken from Hughes, loc. cit., p. i /j 9) indicates 
that in the upper layers of the soil there is, genei-ally speaking, an excess of 
sodium sulphate, while at a depth of 2 5 centimetres, tiiere is a much larger 
proportion of sodium chloride. In addition, Sodium Nitrate, calculated on the 
same basis, is more abundant in the 1 5-2 5 cm. layer than in the 0-1 5 cm. one. 
NUMBERS. 
2 
3 
/i 
5 
f) 
7 
8 
9 
Totals 
Means 
Ratio 
TOP 15 cm. 
SODIUAI 
CHLORIDE. 
0 
3 
.46 
3 
. 2!2 
1 
. 1 2 
2 
.02 
0 
.88 
0 
./i5 
.80 
1 
] 
•79 
2 
..57 
17 
.3i 
SODIUM 
MTRAT1Î. 
0/0 
1 .00 
3./12 
0 . 26 
0 . 5o 
0.7,-) 
0 .hi 
0.75 
0 . 5o 
0.92 
8.5i 
1.92 
Sodium Cliloridc 
Sodium Sulphale 
0.9/1 
SODIUM 
SULPHATE. 
1 4 . 4 2 
2 . 1 3 
2.08 
1 . 4o 
2 11 
0.5/1 
2.11 
3 . 00 
/1.73 
32.5; 
3.61 
SODIUM 
CHLOnlDE. 
NEXT 10 rm. 
S 0 D I U JI 
NITRATE. 
0/0 
8.35 
3.06 
1.10 
1 .28 
1 .00 
o . 37 
1 . 00 
12.98 
1.45 
3./I0 
0/0 
2.7G 
3.28 
0.58 
0.92 
1 . 07 
1.07 
1.17 
1 .33 
12. 18 
1 . 35 
1 : o.3o 
SODIUM 
SULPHATE. 
0/0 
3.0C 
0.55 
0.18 
0.90 
o. 18 
4.28 
9.15 
The source of the salts is in the hills surrounding the plain. 
An interesting example of enrichment near the surface was obtained by 
Mr. Coxon''' from the deposits east of Sibaia. He took samples from successive 
depths of seven inches each, which were analysed for Sodium Nitrate and 
Chloride by Mr. Mc Dowall with the following results : 
DEPTH. 
SODIUM NITRATE. 
1- 7 inches 
0/0 
10.7 
3.7 
9.9 
SODIUJI CHLORIDE. 
0/0 
10.3 
5.8 
(') 
CoxoN, Inspection Report on Sebaia Nilrale Area, i5"' Marcb, 1908. In Mines Dqit. Archives. 
