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Photo by C. A. Harbaugh 

 the: WARNING 



The splendid work of the U. S. Life Saving Service, now known as the Coast Guard, 

 is familiar to all. During the night, winter and summer, in calm or in hurricane, or in case 

 of stormy or foggy weather by day, a guard walks the beach between stations, ready to 

 warn mariners too far inshore of the dangerous reefs by burning colored signals. 



bay. The Susquehanna River in those 

 times flowed to the sea between Cape 

 Charles and Cape Henry. The subsi- 

 dence of the valley let the sea-water in 

 and drowned the Susquehanna out up as 

 far as its present mouth. The Potomac 

 River was then a tributary of the Sus- 

 quehanna, as were also the James and the 

 Rappahannock. 



When we remember that subsidences 

 and elevations of the land have been the 

 rule and not the exception in the geolog- 

 ical history of the world, and that careful 

 studies reveal the fact that they are still 

 taking place, and when we further recall 

 all of the shoreline changes that are go- 

 ing on and which have been recounted 



above, it becomes evident that the geog- 

 raphy of the earth is not a fixed one, and 

 that while nature may change the bound- 

 aries of nations and empires more slowly 

 than man himself is doing and has done, 

 yet the process is going on with such vast 

 and unmeasurable force that man is pow- 

 erless to resist it, and at the same time 

 unable to perceive it unless he calls his- 

 tory to his aid and measures in centuries 

 instead of years. 



The particular attention of the reader 

 is directed to the photogravure series 

 which follow. These unusually beauti- 

 ful studies were made by Mr. H. C. 

 Mann, who takes rank with the foremost 

 photographic artists in the country. 



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