CHAPTER III. 
SECTION LI. 
NARRATIVE OF THE EXPLORATIONS MADE IN 1847, BETWEEN LA POINTE AND ST. LOUIS RIVER; AND 
BETWEEN FOND DU LAC AND THE FALLS OF ST. ANTHONY; AND ON THE ST. CROIX RIVER. 
In accordance with the instructions received from you at La Pointe, on the 5th 
of July, I remained at Madeline Island, after your departure for Stillwater, until 
the 26th of that month, for the purpose of making a series of barometrical observa- 
tions, to be used in referring the various observations throughout the District to the 
elevation of Lake Superior above the Gulf of Mexico, as a standard of comparison. 
Previous to leaving La Pointe, I made arrangements with Mr. Jeremiah Hughes 
of that place, whose acquirements and zeal for scientific investigation well qualified 
him for the task, to institute, in connexion with a meteorological register, a series 
of observations on the so-called “ tides” of Lake Superior (the periodical or accidental 
changes in the level of the lake), phenomena so frequently observed, but the 
cause of which is veiled in so much obscurity. 
He began the observations, and pursued them with diligence for several months, 
but, unfortunately for the interests of science, died before he had carried his inves- 
tigations sufficiently far to admit of generalization. 
Through the kindness of Mr. Rice, of the Fur Company, I took passage, on the 
26th of July, in his boat for Fond du Lac, or, rather, for the Trading-Post of the 
American Fur Company on the St. Louis River. During the passage, I availed 
myself of every opportunity for making observations on the Lake shore ; thus adding 
to the barometrical series begun at Madeline Island. 
Between Madeline Island and Bark Point, red sandstone shows itself on the Lake 
shore for nearly the whole distance. At Pointe Detour, and many other places, the 
bluffs are perpendicular, and from twenty to forty feet in height; and are overlaid 
by beds of sand, drift, red marl, and clay. Beyond the mouth of the small river 
opposite Oak Island, the rock has been worn, by the incessant action of the waves, 
into most singular and interesting architectural forms. Among these, the pillar 
and arch predominate. These Pillared Rocks extend for many miles, and are inte- 
