Thus terminated the first part of our journey, after a tedious voyage of fourteen days, in which we had encountered a series of almost continued head-winds and foul weather. The distance by ship is usually estimated at three hundred miles; by following the indentations of the coast, and entering Saganaw Bay, we found it three hundred and sixty.[20] We found the Huron coast, to the line of which our observations were limited, bearing, in its vegetation, indubitable marks of its exposure to the northern winds. As a section of the lake geology, it is simple and instructive, exhibiting strata of sandstone and non-crystalline and fossiliferous limestone in horizontal positions, without the slightest disturbance in their dip or inclinations. Its mineralogy is scanty, being nearly confined, so far as observed, to some common silicious minerals, and traces of argillaceous and magnetic oxides of iron. The erratic block-stratum or drift, is remarkable, and prepares the mind for the still heavier accumulations of this kind which are perceived to be spread over the northern latitudes.[21] [20] Among the erratic block or drift stratum, I observed on the south Huron coast singularly striking, round fragments of white quartz, imbedding red fragments of coarse jasper; a rock, which I afterwards found in places on the south end of Sugar Island, in St. Mary's Straits, which lies directly north of the general position, and may serve as a proof of the course of the drift. [21] _Vide_ Geo. Report, Appendix. CHAPTER III. Description of Michilimackinac--Prominent scenery--Geology--Arched Rock--Sugarloaf Rock--History--Statistics--Mineralogy--Skull Cave--Manners--Its fish, agriculture, moral wants--Ingenious manufactures of the Indians--Fur trade--Etymology of the word--Antique bones disclosed in the interior of the island.