I 1 4 SEA AND LAND 



this debris is very great, and unlike tlie wrecks it is very 

 evenly scattered along the paths followed by our steam 

 marine. It is likely that already in the track of our trans- 

 atlantic commerce, not a square rod would fail to give a 

 trace of this waste from our coal-burning engines. As this 

 material is not attacked by the marine animals, and is but 

 little affected by the other agents of decay, it will doubtless 

 be very perfectly preserved in the strata which are to bear 

 the records of our time. 



