RED RIVER OF THE NORTH. 171 
the beautiful phenomenon of the mirage. An image of the distant horizon was 
distinctly pictured upon the sky, usually in an inverted position. 
The outlet of this lake into Red River of the North, is at its southwestern 
extremity. The general level of the prairie is thirty-five to forty feet above its 
surface. On one of the elevated points, commanding the entrance to Red River, on 
the south, are six conspicuous dome-shaped mounds, bearing northwest and south- 
east. They appear to be tumuli of the aborigines. 
Descent of Red River of the North (Otter Tail River of the Indians) —About noon 
of the 18th of June, 1848, we commenced the descent of Red River. Since so little 
definite information has hitherto been obtained regarding this stream, it may be 
interesting to note my observations on its character, and the agricultural capability 
and physical geography of the adjacent country, along with the few facts obtained 
on its geology. 
Half a mile from the entrance, on the right bank, is a bed of light yellowish 
gray plastic clay, two and a half to three feet thick. This, I suppose to be a 
sedimentary deposit, derived from the destruction of the marlites, interstratified with 
the beds of Silurian limestone, of which so many fragments are found in the vicinity 
of the lake. 
About four miles farther down the river, the stream becomes very circuitous, and 
expands in width, forming, in the course of the next twenty miles, a series of basins, 
or small lakes, varying from one to two miles across. The first two of these are 
nearly circular, and about a mile in diameter; the bearing of the entrance and 
exit being northeast by east and southwest by west. Their banks are from fifteen 
to thirty feet high. The second of these is connected, by a bend of the river to the 
west, with the third lake, about a mile long, and half a mile wide. Its lower 
extremity curves around to the north. On the left bank, erratic blocks are exposed. 
After coasting around this third lake, we found it had no outlet; we were therefore 
compelled to pass again into the second lake, on the north side of which we discovered 
a strong current; this directed our canoe-men to the entrance into the fourth lake. 
The latter we found separated from the third, by a narrow ridge, of twenty-five to 
thirty feet, of drift. This fourth lake is from half to three-fourths of a mile wide, 
and has its outlet on the north. On leaving it, the river bears away, first to the 
southwest and west, and then northwest and north. 
Two miles below the fourth lake, we came to slight rapids, with boulders in the 
stream, and a few rods beyond, ran a short but swift rapid, with low banks of drift, 
covered with a small growth of oak and birch. 
The waters of Red River are here quite clear, so much so that numerous Cyclas 
could be seen distinctly on the bottom. Its temperature, at three p. M., of the 18th 
of June, was 69°5. 
Just below these rapids, we eneekintiaiels a small party of the Pillager Indians, 
ascending the stream in quest of fish. After a short interview, we continued our 
journey, passing some swampy ground, bearing a growth of tamerack, or American 
larch. 
Eight miles below the fourth lake, we entered the fifth, which is about a mile 
and a half long, and one mile wide, bearing northwest and southeast. Its outlet 
