THE MUD OF MILFORD HAVEN. 27 



ratus is drawn out, the jointed length of gas-pipe is now 

 introduced, the end of it with the rod to which the cork is 

 attached having been previously stopped, the rod passing up 

 the centre of the gas-pipe ; this is let down the hole, another 

 length of pipe being attached, and another length of rod, and 

 so on, length after length of pipe and rod, until the bottom 

 of the hole is reached. We shall thus have a continuous 

 length of gas-piping, which will be penetrated by a con- 

 tinuous length of iron rod attached to the cork at the end of 

 the pipe. It is obvious that this cork will entirely prevent 

 any foreign matter from entering the gas-pipe. Having thus 

 reached the bottom of the hole, now pull up the cork into 

 the gas-pipe about 4 feet, by means of the rod attached to it, 

 and then pi-ess the whole apparatus into the soft mud. The 

 pressure will now drive the mud up into the pipe as far as 

 the cork is drawn up ; now remove the whole apparatus, and 

 by means of the rod push the cork back again to the end of 

 the last length of pipe, when the charge of mud will be 

 driven out in the form of a sausage, and, by rejecting the 

 two ends of it, and taking only the middle piece, we may 

 be perfectly sure that the mud at that depth, and that only, 

 has been obtained. 



Having secured the prize, the short length of piping which 

 contained it is now to be unscrewed, and carefully washed with 

 a common gun-cleaning rod and some tow, when it is ready 

 for another experiment. 



With this apparatus, then, I have penetrated Neyland mud 

 in various places to depths of 20, 30, and 40 feet ; and the 

 results have been so interesting, and the deposits have proved 

 so rich in Diatomaceous remains, that I have been tempted to 

 put some of the results upon paper. 



The first trial I made was at a depth of 20 feet ; and a 

 careful examination of this deposit, when well cleaned, and 

 the coarse sand thoroughly separated, gives us a list of the 

 followins: forms : — 



Epithemia alpestris. 

 Campylodiscus costatus. 

 Surirella biseriata. 

 Navicula ovalis. 



Cocconeis scuteUum, («). 

 „ „ «'• 



,, Grevillii. 

 Coscinodiscus radiatus. 



Fresh- water Species. 



Pinnularia viridis. 



„ radiosa. 



„ major, 



(jromphonema gemiuatum, g. 



Marine, or Brackish. 



Coscinodiscus eccentricus. 



„ Ocelhis iiidis. 



Actinocychis undulatns. 



„ sedenarius. 



Triceratium faviis. 



