Niagara Falls 



1907 published the following year, 1 together with descriptions of the 

 Gilbert monuments and a table of compass bearings from the various 



trigonometric points to objects whose positions were determined 

 by the method of intersection. It was the purpose of this survey 

 to make definite record of the existing position of the crest line 

 and connect this record with permanent monuments, so that by 

 means of a similar survey at some future time the extent of 

 changes might be determined. This purpose it has served. 

 Monuments then placed have been used as starting points in 

 subsequent surveys, and two of them are still extant. 



• • • • • 



In 1875 the second survey of the cres. line was made by the 

 United States Lake Survey under the direction of Maj. C. B. 

 Comstock, the field work being done by F. M. Towar. The 

 United States Geological Survey undertook the third survey, 

 which was made by Robert S. Woodward in 1 886. The fourth 

 survey was made in 1890, by A. S. Kibbe, under the direction 

 of John Bogart, State Engineer of New York, and a very full 

 report was published. In this report the maps of the three pre- 

 ceding surveys are republished, and the crest lines given by those 

 surveys are also placed on the new map. The fifth survey was 

 made in the spring of 1905, by the United States Geological 

 Survey and the State Engineer of New York, the work being 

 done by W. Carvel Hall, and his report follows this paper. 



The Horseshoe Fall. 

 The Horseshoe Fall is at the head of the gorge. From its 

 edges the walls of the gorge run northeastward approximately 

 parallel. The American Fall is at the side of the gorge, 2,500 

 feet from its head, and is separated from the Horseshoe Fall 

 by Goat Island. A few hundred years ago the two falls were 

 together, the position of the united cataract being somewhere in 



1 Nat. Hist. New York, pt. 4, Geology, 1843. Opp. p. 402. 



660 



