48 PUBLIC PARKS OF IOWA 



areas of anomolous topography afford illustrations of McGee's anomalous 

 rivers. In section 5, where the stream crosses the north line of Milo town- 

 ship, the river channel is but a shallow trough in lowan drift, and the 

 drift plain, with little change of level, extends for many miles toward the 

 south. In the east part of section 9 of the same township the stream 

 flows in an old rock-walled valley of erosion approximately 200 feet in 

 depth. The gradient of the stream is not perceptibly changed, the greater 

 depth of the valley being due to the increase in altitude of the general 

 surface in passing from the first to the second point mentioned. 



With one or two unimportant exceptions, the Maquoketa flows in a 

 comparatively deep canyon all the way from sections 9 of Milo township 

 to the south line of Delaware county. At Hartwick, in section thirty of 

 Delhi township, the valley is 190 feet in depth, and at Fleming's mill, 

 a mile east of Hartwick, the depth is 215 feet. In Delhi township and 

 in the northern part of Union the stream valley is cut through a plateau 

 and not through a ridge, as is usual with other anomalous rivers. The 

 pleateau has an extreme width of about ten miles, extending from section 

 23 of Milo township to section 21 of North Fork, and embracing in its 

 eastern margin the valley of Plum creek. Loess hills all around its bor- 

 der rise sixty to eighty feet above the adjacent drift plain, and through- 

 out its entire area of about sixty-five square miles the topography is 

 erosial. Loess hills predominate, but there are some areas covered with 

 sand, and in some places weathered crags of Niagara limestone control 

 the character of the topographic forms. 'Geological Survey, Annual Re- 

 port, Vol. VIII, p. 132-134, 1907. 



THE BACKBONE. 

 By E. M. Carr, Editor and Lawyer. 



Scholarly geologists and noted writers have vied with each other in 

 describing the charming bit of Iowa topography, located in Delaware 

 County and widely known as the "Backbone." 



This noted place has a higher altitude than other locality in eastern 

 Iowa. During the glacial period the "Backbone" stood up like an island 

 in the midst of an ocean of ice. Its surface and the surface of the ad- 

 jacent valleys are free from any trace of lowan drift. 



The view from the highest part of the ridge down the Maquoketa 

 valley for twenty-five or thirty miles has few equals anywhere. It is 

 pleasing and inspiring to see how the gateways of the prairies open to 

 let the river come out. 



The tourist who visits Virginia is told that he should not return home 

 until he has seen the Piedmont valley near Afton, a valley no more in- 

 viting or beautiful to behold than the Maquoketa valley when viewed 

 from the culminating point of the "Backbone." 



The "Backbone' ridge extends nearly north and south for a distance 

 of about 200 rods. The river runs down on the west side, turns around 

 the south end and flows back along the east side. 



The narrowest point of the ridge is about midway between its ex- 



