deposits of sufficient duration to allow of the consolidation of the 

 lower bed before the other was thrown down upon it. Therefore, 

 to learn the true history of the beds, we must discover the cause of 

 the pipes ; the action is so similar in the chalk and the detrital de- 

 posits that the one will explain the other. 



From recent study of the pipes or sandgalls in the chalk of a part 

 of Kent, Mr. Trimmer has arrived at the conclusion that they are 

 due to the mechanical, not to the chemical action of water ; and that 

 this action was the breaking of the sea on a low shore antecedent to 

 the formation of the eocene strata. This opinion he bases on the 

 following grounds. 



Having had an opportunity of observing the removal of its cover- 

 ing from the chalk near Faversham, Mr. Trimmer found that the 

 pipes were but the terminations of furrows from six to twenty-four 

 inches deep in the shallowest parts exposed, but widening and deep- 

 ening as they approached the pipes till they were lost in them. 



The diluvial covering spread over the chalk is a strong loam of a 

 reddish brown colour, with numerous unabraded flints dispersed 

 through it. The pipes were filled with loam of a more sandy nature 

 and of a much lighter colour. The few pebbles found in them con- 

 sisted of chalk flints much water-worn, and contrasting strongly with 

 the unabraded flints of the diluvium. Their sides were lined with 

 clay, tinged black. The lower part of the diluvial deposit, near its 

 junction with the chalk, had in many places the same black tints. 

 None of the pipes terminated downwards in a point, the apices of 

 the inverted cones being three or four inches broad. These facts 

 the author considers indicative of the mechanical action of water. 



He observed certain blocks of siliceous sandstone, derived from the 

 sands of the London clay, marked with similar pipes and furrows, 

 though of smaller dimensions, which could not have been formed by 

 the action of acidulated water. In these the pipes occasionally com- 

 menced from the opposite sides of the same block, perforating it, 

 therefore not formed by rain. On the sea-shore near Reculver he 

 saw similar blocks, presenting pipes in miniature. The waves charged 

 with small pebbles and sand, wearing the surface with furrows like 

 those of the chalk, the softer parts of the stone then giving way, 

 first hollows are formed, then the rotatory motion of the contents 

 of the hollows, set in action by the influx and reflux of the waves, 

 drills the pipe. 



The pipes and furrows in the sandstone blocks Mr. Trimmer con- 

 siders as having been produced by the same agency, and their perfo- 

 ration, as caused in consequence of their reversion by a violent storm 

 and the drilling operation then going on at the opposite side. 



The examination of a chalk bed near Canterbury convinced Mr. 

 Trimmer that the same causes had produced the pipes and furrows 

 in the chalk. He remarks, that the sand with which the pipes were 

 filled contains much calcareous matter, and that it appears impossible 

 that acidulated water, percolating from above, could have acted on 

 the chalk without first removing all carbonate of lime from the sand. 



In all cases observed by Mr. Trimmer the sandgalls were confined 



