The Problem: How great are erosional contrasts in Indiana; what influences have produced them? The Method: An analysis of the soil erosion map recently issued by the United States Soil Conservation Service has been made; field observations have been made in all the counties of the State, in order to add supplementary data; maps showing the distribution of several factors presumably contributing to the causation of the contrasts were prepared and compared in detail with the erosion maps. Conclusions: Despite moderate differences with respect to elevation, relief, lithology, structure, geologic history, and climate, Indiana has notable regional contrasts in soil erosion. Factors causing these include contrasts in local relief, soil types, recency of glaciation, climate, and land use. Climatic contrasts clearly have played a larger part than has hitherto been appreciated. Regional contrasts in rainfall intensity—a factor hitherto almost ignored, because evidence as to its existence had not . . .