514 H. S. Howorth — Traces of a Great Post-Olacial Flood. 



impalpable chalk paste full of small and large angular and rolled 

 fragments of chalk, and this chalk paste occasionally replaced by 

 sauds apparently of Tertiary origin, almost unmixed, and as though 

 lifted up and transported bodily, and without being broken up. 

 The whole mass is roughly stratified into certain divisions ; but 

 in each division the materials are mixed together perfectly independ- 

 ently of their specific gravity. Impalpable chalk silt, which the 

 most gentle ciirrent, if maintained, would remove, is found envelop- 

 ing masses of broken chalk-flints, whilst large massive flints, scarcely 

 at all worn or broken, and requiring for their transport considerable 

 power, are found dispersed indiscriminately in the finest sediment 

 and in the coarse shingle. The flint-rubble is also often heaped or 

 piled, as it were, together, giving rise to a roughly contorted 

 appearance. Further, a deposition under the ordinary conditions of 

 accumulation in water would have led to the probability of traces 

 of the contemporaneous fauna occurring. It seems to me probable, 

 that the action which led to the accumulation of this drift was 

 sudden, powerfid, tumultuous, not of long continuance, and suddenly 

 arrested. At the same time I do not believe that it was of a 

 nature to break and fractui'e the great mass of angular flints ; but 

 these having been in great part broken and shattered by previous 

 disturbances, while in the body of the chalk, that they were re- 

 moved, not so mucli, by rolling at the bottom of the water, as by 

 transportation in mass with the ivaters. Such a force, while it 

 would uproot and tear away large portions of the chalk and 

 tertiaries, might, if the distance were not great, transport, com- 

 paratively unbroken, masses of the softer strata, and even the more 

 delicate shells which they contain. The condition of the mass 

 would depend, therefore, entirely upon the distance which it had 

 travelled, and the nature of the ground over which the waters passed. 

 If we suppose a large body of water to be moving with a velocity 

 sufficient to transport large blocks, then necessarily, the smaller 

 debris and the mud and silt would be carried along with them ; but 

 when the velocity is only sufficient to move the finer debris, then the 

 larger blocks and coarser materials must be left behind. In the 

 former case tlie heavier portions would subside first, and the lighter 

 ones be carried to a distance and become gradually more worn. But 

 let this current be arrested in the early part of its course, and then 

 we shall have a deposit of mingled debris, the less sorted the nearer 

 we approach to its point of origin, and if this should be effected after 

 a short transport, and without meeting with any material impedi- 

 ments, then masses of clay and sand with their imbedded organic 

 remains, however delicate, as well as the bones of animals occurring 

 on the surface of the ground, may, I apprehend, be transported com- 

 paratively uninjured and unbroken. Should, however, any impedi- 

 ments occur to obstruct their progress, or any conflicting currents 

 disturb the uniform and regular sweep of the moving mass, then the 

 clash of the debris will more or less break and wear both the organic 

 remains and the rock detritus in proportion to their hardness and 

 power of resistance ; the more friable and delicate specimens being 



