112 PUBLIC PARKS OF IOWA 



water in the river. The extremely circuitous meanders in the vicinity 

 of Eagle City and Hardin City marks the Altamont moraine crossing. 

 The Gifford terrace is easily traceable to Hardin City, where it has an 

 elevation of thirty-five feet above the flood plain. At Steamboat Rock 

 where it reaches its maximum it is sixty-five feet above the flood plain. 

 The constituent gravels are much coarser at both of these points than 

 at Gifford and Union. At least two other terraces may be noted above 

 this and the stream is engaged at present in cutting one below. At 

 Hardin City the upper terraces are forty-five and seventy-feet, and at 

 Steamboat Rock ninety-five and 110 feet, above low water in the river, 

 lowan boulders were noted in abundance on the ninety-five foot bench. 

 Northeast of Eldora the gravel bench, which rises about seventy-five feet 

 above the river, is probably the continuation of the second terrace at 

 Steamboat Rock. The materials are much finer and stratification planes, 

 though much interrupted, are very prominent. Fragments of these ter- 

 races may be viewed at other points. The terrace now forming is al- 

 ready out of reach of high water. It varies from fifteen to twenty feet 

 above low water level. The Iowa Central railway is built on it between 

 Steamboat Rock and the point where the railway leaves the river val- 

 ley north of Eldora. This terrace is also sought out by the C., I. & D. 

 railway for a mile or two either side of Xenia. In the latter region the 

 bench is in part rock supported. Below Union the Gifford terrace merges 

 with the one now forming and thus continues into Marshall county. 



Beyond Hardin City there is a marked change in the topographic fea- 

 tures; the bluffs recede from the river, and the contours are markedly 

 softened. The gravel terraces which characterize the valley cross-section 

 in its lower course become less prominent and beyond Eagle City prac- 

 tically disappear. The Eldora sandstone, underlain with shales which 

 engender a bold relief, has given place to the limestone of the lower 

 carboniferous. The change in indurated rocks is clearly recorded in the 

 landscape. At Eagle City the river has made an incision into the lime- 

 stone of some forty feet. This state of affairs, although more or less 

 obscured by drift talus, persists to the vicinity of Iowa Falls. Here the 

 stream flows through a limestone gorge which attains a maximum depth 

 of seventy feet at the Iowa Central railway bridge. The retreating drift 

 bluffs rise some fifty feet higher. At this point the stream has been dis- 

 placed in very recent times. There is a well marked channel south of the 

 Bliss annex, now sought out by the C., I. & D. railway. This depression 

 closely parallels the present channel to the eastward, and also toward 

 Alden. The so-called "Rapids of the Iowa," or "Iowa Falls," from which 

 the town is named, the canyon-like gorge of the river itself, and its inlets, 

 Rock Run, Wild Cat Glen and Elk Run, all owe their origin to this dis- 

 placement. In fact the accidental blocking of the old channel by the ice, 

 which necessitated the cutting of a new one, has given the surface a pic- 

 turesque ruggedness which renders Iowa Falls unique among interior Iowa 

 towns ; and for natural beauty it is without a peer. Westward the stream 

 walls are less gorge-like. Low rock walls appear almost constantly on 

 one or both sides of the stream as far as Alden. North of Alden the in- 

 durated rocks disappear, the bluffs become more subdued and the stream, 

 soon after passing over into Franklin county, takes on the character of a 



