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Show 262 DENUDATION OF rrnE LAND CHAP. VI. me after heavy rain, in many places on lanJ of all kinds. On the flowing of wet castings, and the rolling of dry d'isintefp·ated castings down inclined su1:[aces.-When castings are ejected on an inclined surface during or shortly before heavy rain, they cannot fail to flow a little down the slope. Thus, on some steep slopes ju l{nole Park, which were covered with coarse grass and had apparently existed in this state from tinw immemorial, I found (Oct. 22, 1872) after several wet days that almost all the many castings were considerably elongated in the line of the slope; and that they now consisted of smooth, only slightly conical masses. Whenever the mouths of the burrows could be found from which the earth had been ejected, there was 1nore earth below than above them. After some heavy storn1s of rain (Jan. 25, 1872) two rather steeply inclined fields ncar Down, which had formerly been ploughed and were now rather sparsely clothed with poor grass, were visited, and n1any castings extended down the slopes for a length of 5 inches, which was twice or thrice the usual diameter CIIAP. VI. AIDED BY WORMS. 263 of the castings thrown up on the level parts of thes~ same fields. On some fine grassy slopes 1n Holwood Park, inclined at angles between 8° and 11° 30' with the horizon ' · where the surface apparently had never bee~ disturbed by the hand of man castino-s ' 0 abounded in extraordinary numbers : and a space 16 inches in length transversely to the slope and 6 inches in the line of the slope, was completely coated, between the blades of grass, with a uniform sheet of confluent and subsided castings. Here also in many places the castings had flowed down the slope, and now formed smooth narrow patches of earth, 6, 7, and 7 k inches in length. Some of these consisted of two castings, one above the other, which had become so completely confluent that they could hardly be distinguished. On my lawn, clothed with very fine grass, most of the castings are black, but some are yellowish from earth having been brought up from a greater depth than usual, and the flowing-down of these yellow castings after heavy rain, could be clearly seen where the slope was 5°; and where it was less than 1° some evidence of their flowing down could |