OF ORGANIC NATURE 29 



But, although one of the greatest difficulties of the 

 historical student is cleared out of our path, there are other 

 difficulties difficulties in rightly interpreting the facts 

 as they are presented to us which may be compared 

 with the greatest difficulties of any other kinds of historical 

 study. 



What is this record of the past history of the globe, 

 and what are the questions which are involved in an inquiry 

 into its completeness or incompleteness ? That record is 

 composed of mud ; and the question which we have to 

 investigate this evening resolves itself into a question 

 of the formation of mud. You may think, perhaps, that 

 this is a vast step of almost from the sublime to the 

 ridiculous from the contemplation of the history of the 

 past ages of the world's existence to the consideration of 

 the history of the formation of mud 1 But, in nature, 

 there is nothing mean and unworthy of attention ; there 

 is nothing ridiculous or contemptible in any of her works ; 

 and this inquiry, you will soon see, I hope, takes us to the 

 very root and foundations of our subject. 



How, then, is mud formed ? Always, with some trifling 

 exception, which I need not consider now always, as the 

 result of the action of water, wearing down and disinte- 

 grating the surface of the earth and rocks with which it 

 comes in contact pounding and grinding it down, and 

 carrying the particles away to places where they cease to 

 be disturbed by this mechanical action, and where they 

 can subside and rest. For the ocean, urged by winds, 

 washes, as we know, a long extent of coast, and every wave, 

 loaded as it is with particles of sand and gravel as it breaks 

 upon the shore, does something towards the disintegrating 

 process. And thus, slowly but surely, the hardest rocks 

 are gradually ground down to a powdery substance ; and 

 the mud thus formed, coarser or finer, as the case may be, 

 is carried by the rush of the tides, or currents, till it reaches 

 the comparatively deeper parts of the ocean, in which it 

 can sink to the bottom, that is, to parts where there is a 

 depth of about fourteen or fifteen fathoms, a depth at which 

 the water is, usually, nearly motionless, and in which, of 

 course, the finer particles of this detritus, or mud as we call 

 it, sinks to the bottom. 



Or, again, if you take a river, rushing down from its 

 mountain sources, brawling over the stones and rocks that 

 intersect its path, loosening, removing, and carrying with 



