NATURAL WATERWAYS IN THE UNITED STATES HARTS. 549 



is to be found. These inland seas are of enormous commercial ad- 

 vantage, and nowhere in this country can we point to an instance 

 where the water routes have increased in usefulness to a greater ex- 

 tent than here. The depth of these lakes, the extent, and strategic 

 location with regard to a special class of traffic make them superior 

 in point of tonnage to any other system of interior waterways any- 

 where. The iron ore deposits at the western end of Lake Superior 

 are the most important in the world ; and the coal deposits in west- 

 ern Pennsylvania are of a magnitude and quality that make them 

 a worthy complement to the ore fields, and well able to make the 

 United States what it has become in the last 20 years — one of the 

 foremost producers of iron in the world. Over one-half of the traffic 

 of this lake system is iron ore shipped from about four ports on the 

 western shore of Lake Superior to about a half dozen ports on the 

 southern or southwestern shore of Lake Erie. The Lakes in them- 

 selves present excellent chamiels for navigation, but obstructions at 

 the falls in St. Marys Elver, lying between Lake Superior and Lake 

 Huron, were a complete bar to the navigation of these lakes, up 

 to 1855. At this time the portage railroad previously built around 

 St. Marys Falls, in order to make possible shipments of ore by water 

 over the remainder of the distance, was superseded by the first lock 

 canal around St. Marys Rapids. This canal was of comparatively 

 small dimensions, but demonstrated the possibility of this method 

 of handling freight. It was built by the State of Michigan, and 

 admitted vessels drawing up to 11.5 feet, and cost about $1,000,000. 

 This money was raised by selling 750,000 acres of public land donated 

 by the United States Government for this purpose. In 1870 the 

 United States undertook to widen the canal and increase the capacity 

 of the locks, the entire existing work having been turned over to the 

 United States by the State of Michigan and freed from tolls some 

 years before. This new lock, known as the Weitzel Lock, was opened 

 to traffic in 1881 at a cost of about two and two-thirds millions of 

 dollars. Commerce responded at once to these new facilities, and in 

 1886 a third lock was commenced. This was built on the site of one 

 of the old State locks and was opened to navigation in 1896. It cost 

 about four and three-quarter millions of dollars and is known as the 

 Poe Lock. It is 800 feet long by 100 feet wide, and admits vessels 

 drawing up to 17.7 feet. This lock was soon inadequate, as the com- 

 merce developed more rapidly than the Government provided facili- 

 ties, and in 1907 a project for an additional lock with its own sepa- 

 rate canal was adopted at an extimated cost of $6,200,000. It will 

 have a length of 1,300 feet in the chamber, 80 feet width, and have a 

 depth of 24.5 feet on the sills. (See pi. 1. fig. 1.) This lock is now 

 imder construction, nearly all of lock masonry being now finished. 

 In 1912 a project for a fourth United States lock was adopted to have 

 73839°— SM 1916 36 



