below it, the men being much exhausted with these attempts.  We renewed the effort with a cordelle the next morning, with success, but not without exhausting the men so much that two of them refused to proceed, who were immediately paid off, and furnished provisions to return.  We succeeded in going to the mouth of the Obrazo, about half a mile higher, when we lay by all day.  This delay enabled Ensminger to recruit his crew, and during the three following days we ascended respectively six, seven, and ten miles, which brought us to the commencement of Bois-brule bottom.  This is a fertile, and was then a comparatively populous, settlement.  We ascended along it about seven miles, the next day seven more, and the next eleven, which completed the ascent to the antique town of St. Genevieve.  About three hundred houses were here clustered together, which, with their inhabitants, had the looks which we may fancy to belong to the times of Louis XIV. of France.  It was the chief mart of the lead mines, situated in the interior.  I observed heavy stacks of pig lead piled up about the warehouses.  We remained here the next day, which was the 20th of July, and then went forward twelve miles, the next day thirteen, and the next five, which brought us, at noon, to the town of Herculaneum, containing some thirty or forty buildings, excluding three picturesque-looking shot towers on the top of the rocky cliffs of the river.  This was another mart of the lead mines.

I determined to land definitively at this point, purposing to visit the mines, after completing my ascent by land to St. Louis.  It was now the 23d of July, the whole of which, from the 1st, we had spent in a diligent ascent of the river, by setting pole and cordelle, from the junction of the Ohio—­a distance of one hundred and seventy miles.  We were still thirty miles above St. Louis.

I have detailed some of the incidents of the journey, in order to denote the difficulties of the ascent with barges prior to the introduction of steam, and also the means which this slowness of motion gave me of becoming acquainted with the physical character of this river and its shores.  A large part of the west banks I had traveled on foot, and gleaned several facts in its mineralogy and geology which made it an initial point in my future observations.  The metalliferous formation is first noticed at the little chain of rocks.  From the Grand Tower, the western shores become precipitous, showing sections and piled-up pinnacles of the series of horizontal sandstones and limestones which characterize the imposing coast.  Had I passed it in a steamer, downward bound, as at this day, in forty-eight hours, I should have had none but the vaguest and most general conceptions of its character.  But I went to glean facts in its natural history, and I knew these required careful personal inspection of minute as well as general features.  There may be a sort of horseback theory of geology; but mineralogy, and the natural sciences generally, must be investigated on foot, hammer or goniometer in hand.