408 Transactions. — Geology. 



pools, and very sparsely scattered through the present sub- 

 soil elsewhere. Similar granules are to be found scattered 

 thinly throughout the mass of the loess, but they are distinctly 

 numerous in these bands. These granules must have taken 

 some time to form, and other evidence is forthcoming in proof 

 that the layers in which they occur respectively formed a soil 

 and subsoil for very long periods of time. It is to be inferred, 

 too, that the ore-granules indicate the prevalence of a very 

 wet climate during the whole or some portion of each of these 

 periods, as such granules do not appear to be formed except 

 in wet soils. The climates must have been very wet, as the 

 curvature of the granule-bands is such that the land-surface 

 which each represents was well drained. The buried peat-bed 

 already described is easily traced outwards into one of these 

 granule-bands. 



Humus-stains. — The vestiges of the successive generations 

 of vegetation have been almost but not wholly obliterated. It 

 would seem that the growth of the deposit was so slow as to 

 nearly allow the rootlets of each generation of plants to suck 

 up the last remnant of the decay of previous ones. Nearly, 

 not quite. Whenever a cutting is newly made, or a fresh face 

 is formed on a sea-cliff, there is observable from top to bottom 

 a brownish stain in the clay, which is intensified a little in 

 certain bands. This stain disappears after a short exposure 

 to the air, the surface soon assuming a bright-yellow " clay " 

 colour. The uppermost of these dark bands, which varies in 

 position from 5ft. to 8ft. or so beneath the present soil (and in 

 some places also the second band, some feet lower down), 

 shows in old "backs," or natural crevices, abundant stains 

 caused by the decay of rootlets, the ramifications of which 

 can be easily traced. This evidence, taken alone, would not 

 be of much value, as recent rootlets — very few in number, 

 however — penetrate these cracks. The obscure brown stains 

 in deeper bands, to which recent rootlets do not extend, are 

 evidently of the same character as the more strongly marked 

 upper ones, and I have no doubt that these darker bands, and 

 the more diffused stain of the spaces between them, are due 

 to a trace of humus remaining in the successive subsoils. 

 The ore-granule bands previously described are the repre- 

 sentatives in a weathered face of the bands of darker stain in 

 a fresh face of the clay. Such granules of ore are frequently 

 formed in the present subsoil in the shape of pipes around 

 decaying roots. I have found in the granule-bands specimens 

 which bore on a concave surface plain imprints of vegetable 

 form. At a low level in the deposit there is to be seen here 

 and there a stratum of fine, dense, somewhat plastic clay (as 

 Sir J. von Haast well described it in one of his reports), which, 

 from the positions in which it occurs, can be nothing else than 



