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The rates of solifluction of two lobes in the Ruby Range have been determined by 14C dates of samples taken from buried organic layers in the lobes. Twenty-one dates are available from one lobe, and seven from another. When plotted against distance back from control points at the lobe fronts the dates show considerable scatter. In part the scatter is thought to be due to a potential age range of 340 ± 100 yr in the organic layers. Linear and polynomial regressions were calculated for the time/distance relationships shown by the dates. The rates of lobe advance established by these means for the lobe with seven dates are not thought to be reliable. Reasonably good estimates of movement rate were determined for the second lobe by both the linear and polynomial methods. However, the rates established by the two methods are quite similar. Because of this and other uncertainties it is difficult to draw inferences of climatic change from the changes in movement rate shown by the polynomial solution.

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The meander loop pattern of the lower Ohio River has changed very little over the last thousand years. Point bar complexes are deposited and destroyed quite rapidly in comparison. KEY WORDS ; Channel stability, Meanders, Ohio River, Point bars.ADIOCARBON dates of organic matter R from the Black Bottom alluvium indicate that the meander loops of the lower Ohio River between Evansville, Indiana, and Brookport, Illinois, have an unusual degree of stabi1ity.l These dates suggest that the Bottom had reached its present outline, at least in the eastern half, by 1,000 years ago or earlier.Since lateral stability of sinuous alluvial channels seems to be relatively rare, the recent history of the Black Bottom portion of the Ohio channel was studied by comparing the original land survey maps, resurveys, topographic maps, and air photographs. We were curious whether other meander loop bottoms on the lower Ohio exhibited the same degree of stability, so we extended the comparison between the land survey maps and recent topographic maps upriver to Evansville, Indiana. GENERAL SETTINGThe meander loop floodplains between Brookport and Evansville have several features in common. Their surfaces all have a topography of ridges and swales, remnants of meander point bar deposits that indicate the river channel has migrated extensively. The loop floodplain surfaces, or bottoms as they are locally called, are higher on their upstream than

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