Sinkhole Plain

Logsdon River has been explored upstream from the confluence for more than seven kilometers. It more or less parallels the escarpment at the southern edge of the Mammoth Cave Plateau and is a master drain for the karst as far northeast as Roppel Cave. It is known to receive recharge from valley drains and vertical shafts and also from the sinking streams and sinkhole inputs on the Sinkhole Plain to the southeast. The Logsdon River sediments are mainly silts and fine sands with 40 - 60% of the material smaller than the smallest sieve size used. 

The contrast between the two tributaries could be a matter of provenance, a contrast between sediment derived from the Plateau compared to sediment derived from the Sinkhole Plain, it would also be a matter of transport with Hawkins River being the higher energy stream. 

Sediments were also subsampled from each of the four stratigraphic layers of the sequence. In order to examine the relationship of cave sediments to modern, nearby depositional settings, samples were also collected from a nearby sinkhole pond with hand operated coring device and from the high terrace and flood plain soils with a shovel (Fig. 1). 

---