Ecology of the Cincinnati Region 
159 
(Thalictmm dioicuni), Hepatica (Hepatica acntiloba) and Christmas fern 
(Polystichum acrostichoides ). 
Southzvard flowing streams. —The forests developed along the steep 
southward flowing streams are always less mesophytic than those of the 
northward slopes. It is only in very sheltered spots that a truly meso¬ 
phytic association is found. Elsewhere, the associations are xero-meso- 
phytic or even xerophytic on the steepest slopes. Beech is almost always 
absent, and sugar maple is not everywhere abundant. Instead of Dicentra 
and Erythronium, are larkspur (Delphinium trieorne), false rue anemone 
(Isopyrum biteniatum), and wild hyacinth (Camassia eseulenta). 
The short steep ravines seldom carry permanent streams. The slug¬ 
gish lower course is always short. The marginal vegetation, if present 
at all, is hardly more than an inward lobe of the marginal flood plain 
association of the larger stream. 
Absenee of gorge. —In a number of streams of the region, the gorge¬ 
like valley through the Eden shale is absent. This is due either to the 
relatively high level of the stream into which the tributary flows or to the 
deep and broad valley filling through which the little stream must cut 
during the latter part of its course. The altitude of the Eden-Maysville 
contact is a contributing factor in the elimination of the gorge-like valley. 
Elongated sluggish eourse. —When the stream must cross a broad 
flood plain, or flow through a filled valley, the sluggish part of its course 
is often long. This is true of many streams flowing into the Little Miami 
below East Eork, and of some flowing into the Ohio. But the greatest 
development of this sluggish portion of the stream course is found along 
Mill creek valley. In fact, Mill creek flows for most of its length through 
the wide pre-glacial valleys of the Ohio and Licking rivers. 
Streams at edge of Wiseonsin drift. —Eour streams in the region, 
Simpson creek, Sharon creek. West Eork of Mill creek, and Banklick 
creek, flow for part of their courses, at or very near the margin of the 
Wisconsin drift (Cincinnati Eolio). These streams were in places pushed 
southward by the advancing ice, and so forced to cut new channels 
through rock. In this part of the course, whether the stream is cutting 
through Maysville or through Eden shale, the valley is very narrow and 
deep, and the sides steeper than found along the typical ravine. Fig. go 
shows the gorge in the Eden shale and the narrow valley of Banklick 
creek. The south slope is quite xerophytic, except near the base. The 
north slope is damp, and even on the open parts, a number of shade plants 
are found. 
