A disadvantage of the loess lies in the readiness with which it washes. The forest which once covered nearly all the uplands protected the soil from wash by means of its mattress of roots and the thick prairie sod was equally efficient where hill slopes were grassed over. But where forests have been thoughtlessly cut down, and steep slopes turned to plow land, it is but a few years until the brown top-soil is all washed away and the fields in spring when freshly plowed are as yellow as a deep cut in road or brick yard. The foot path in the pasture or the furrow of the plow becomes a gully in a single heavy rain, and unless checked soon becomes a gulch scores of feet in width. By accenting the height of the ridges the loess also adds to the scenery of the county. Our area lies in a part of east central Iowa where the stony clays deposited by ancient glaciers accumulated in long ridges and belts of upland rising many feet above the intervening undulating plains. Because of the alternation of ridge and lowland no part of the state except the valley of the Upper Mississippi has so beautiful and wide and varied prospects. Over more or less of their course the rivers of the county have cut their channels lengthwise in the ridges, thus giving rise to the bold scenery of the Wapsipinicon above Central City, and of the Cedar near Mount Vernon. Some of these picturesque reaches of river and cliff and forest slope should surely be converted into county parks in the near future and preserved for the gratification of all coming generations. Unless this is done we may expect that the forests will be cut down and the hill slopes gashed with countless gullies; while the lichened rocks of the river cliffs fringed with fern and tamarisk will give place to unsightly quarries. While Linn county was sheeted with glacier ice, no life of any sort was possible within its limits. But during the long interglacial epochs which intervened between the ice invasions, forests grew and animals now extinct roamed over our hills and plains. Among these early inhabitants may be mentioned extinct horses and the giant proboscidians, the mammoth, and the mastodon. These returned to the area after the final retreat of the ice and their remains are found in the peat bogs and river gravels. In the earliest of the interglacial epochs it is quite probable that some of the gigantic groundsloths of South America made their home here, since they are known to have done so in the western counties of the state. No traces of man have been found in the glacial deposits of Iowa, nor have any indubitable evidences of his presence in glacial times been found in North America. Sometime, we know not when, roving tribes of Indians set foot within our area, and geology gives place to archeology. And when the white man appeared, inductive history ends and there begins the history of tradition and written records. CHAPTER VI _Beginnings in Linn County_