3 



in an unusual form. Some may have been present in the form of 



fragments of marine or fresh water shell. By far the larger proportion 

 \va.s found in the coarser fractions as small grey agglomerations or 

 concretions. This rather suggests that since the alluvium was depo- 

 sited the carbonate of lime, occurring in fine particles, had been 

 dissolved by the water of the overflow and had been redeposited 

 in. these small granules. These particles did not consist of pure 

 carbonate of lime, but rather of a mixture of carl>ona,te of lime, magnesia. 

 and iron (ferrous); these accretions seldom exceeded a millimetre in 

 diameter. It was not found practicable to collect a. sufficiently pure 

 material to make a, quantitative examination, but qualitative tests 

 showed them to possess the composition indicated above. 



It was noted that over much of 1 he area t lie sa.mples from two and 

 three metres depth exhibited an almost black appearance even when 

 dry and in a fine state of division. This colour appeal's to be due to 

 the presence of partially carbonized vegetable remains. Sulphide of 

 iron could not be detected. Small fragments of vegetable debris were 

 easily separated from this black subsoil. From the appearance of 

 t liese under t he microscope it seemed probable t hat this debris consisted 

 largely of the fragmentary remains of rushes or similar marsh plants. 

 The black soil showed traces of ferrous iron. 



TAHI.K I. A.MOUNT OK (IAI:I:ON.\TIO OK LI\IK |'I;KSK.\T IN TIIK Sou, AT 10 

 POINTS AT TIIK. SintKAcic AND AT DEPTHS OK O\i:. Two, AND TIIRKK 

 METRES. 



