The new Northwest was settled after the great day of the keelboat on western waters. Iowa and the lead country had been reached by the steamboats of the Mississippi. The Milwaukee district was reached by the steamboats from the lakes. The upper Mississippi frontier was now even more thoroughly dependent on the river navigation than its neighbors had been, while its first period was over before any railroad played an immediate part in its development. The boom period between the panics of 1837 and 1857 thus added another concentric band along the northwest border, disregarding the Indian frontier and introducing a large population where the prophet of the early thirties had declared that civilization could never go. The Potawatomi of Iowa had yielded in 1846, the Sioux in 1851. The future of the other tribes in their so-called permanent homes was in grave question by the middle of the decade. The new frontier by 1857 touched the tip of Lake Superior, included St. Paul and the lower Minnesota valley, passed around Spirit Lake in northwest Iowa, and reached the Missouri near Sioux City. In a few more years the right wing of the frontier would run due north from the bend of the Missouri. The hopeful life of the fifties surpassed that of the thirties in its speculative zeal. The home seeker had to struggle against the occasional Indian and the unscrupulous land agent as well as his own too sanguine disposition. Fictitious town sites had to be distinguished from the real. Fraudulent dealers more than once sold imaginary lots and farms from beautifully lithographed maps to eastern investors. Occasionally whole colonies of migrants would appear on the steamboat wharves bound for non-existent towns. And when the settler had escaped fraud, and avoided or survived the racking torments of fever or cholera, the Indian danger was sometimes real. Iowa had advanced her northwest frontier up the Des Moines River, past the old frontier fort, until in 1856 a couple of trading houses and a few families had reached the vicinity of Spirit Lake. Here, in March, 1857, one of the settlers quarrelled with a wandering Indian over a dog. The Indian belonged to Inkpaduta's band of Sioux, one not included in the treaty of 1851. Forty-seven dead settlers slaughtered by the band were found a few days later by a visitor to the village. A hard winter campaign by regulars from Fort Ridgely resulted in the rescue of some of the captives, but the indignant demand of the frontier for retaliation was never granted. In spite of fraud and danger the population grew. For the first time the railroad played a material part in its advance. The great eastern trunk lines had crossed the Alleghanies into the Ohio valley. Chicago had received connection with the East in 1852. The Mississippi had been reached by 1854. In the spring of 1856 all Iowa celebrated the opening of a railway bridge at Davenport.