GEOLOGICAL ACTION VS. ENGINEERING. 17 



and social economy, and that has made of mankind hostile states and warring 

 peoples. In the order of development this continent seems to have been 

 reserved for a polyglot race, without entangling traditions and with a configura- 

 tion that makes them one people and one great interest. Our mountain r;inges 

 throw the rivers to a common outlet, and the valleys cannot be populated by a 

 divided people. To these the progress of science and discovery have furnished 

 the methods of intercommunication so rapid and intimate that the health giving 

 elevated lands of the interior can be utilized as readily as the marine coasts, and 

 thus the race takes its return movement to the sources of its origin and in search 

 of a development more grand than it has ever known. This is the lesson taught 

 by these figures of the census. 



GEOLOGICAL ACTION vs. ENGINEERING.— THE RIVER AND THE 



GULF. 



An engineer in the service of the United States, in describing an engineering 

 performance at the mouth of Pascagoula river, drops a few remarks in the way of 

 casual commentary which may escape general notice, but which are nevertheless 

 of considerable importance to the public. It was no mean engineering feat which 

 he was describing. A Hght-house at Pascagoula inlet, built upon screw-piles, was 

 threatened with destruction by the action of the sea. The screw-piles had not 

 penetrated below what might be called the surface sand of the coast, and the 

 shifting of these sands threatened to undermine the supports of the light-house. 

 A new foundation was built three hundred feet distant, by driving wooden piles 

 seventy feet long, and the building was moved on a trestle built from the old to 

 the new supports. During the period of transfer the light was kept burning as 

 usual, and the whole operation was marked by a rare exercise of engineering 

 skill. But in summing up, the engineer remarks that the outlying islands along 

 the gulf coast were evidently formerly farther out at sea, and are gradually under- 

 going a process of erosion and re-deposit which is removing them farther inland. 

 In boring on the new site of his light-house he found below the surface-sands the 

 remains of a shore marsh, with the plants in a good state of preservation, and he 

 infers from this and other considerations that the shore of the gulf is subsiding, 

 and that the Mississippi river is backing up. Perhaps he has other observations 

 behind this conclusion, but his apparently incidental inference is one which it is 

 at least worth while for the government to notice. 



If the gulf coast is really undergoing a slow subsidence, the fact ought to be 

 verified. It is undoubtedly true that the lower Mississippi is less able to discharge 

 the water that comes down from above than formerly. The levees, which were 

 once adequate to protect the bottoms from overflow, have now become so liable 

 to fracture when the river is but moderately full, that little reliance is placed on 

 them. This has been attributed to the gradual elevation of the bed of the river, 

 and the scouring of the river bed to a greater depth is the object of the plan of 



V— 2 



