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-16- Thus, the complete set of basic morphometric data for each watershed includes area, perimeter, total length of stream channels, length of the main channel, and a coded vector of network composition. All of these properties are potentially important in evaluating the hydrologic re- sponse to urbanization because they represent the spatial pattern within which hydrologic processes occur and reflect the amount and time distri- bution of runoff. The drainage network of the Neponset basin is presen- ted in Figure 4 on which both the Strahler ordering and the coded network vector are shown. This unusual and irregular channel pattern is fairly typical of the glacial terrain in the study area. . . Surficial Materials Information concerning the character of the land surface within each watershed was derived from a combination of topographic map interpreta- tion and U.S. Geological Survey surficial geologic quadrangles. Areas in Rhode Island were evaluated by means of groundwater maps which closely correspond with the surficial geology. Soils maps of the U.S. Soil Conservation Service were not utilized because of their reliance on cri- teria other than texture. No uniform data source exists which would pro- vide complete coverage of the study area at a suitable scale, hence some interpretation of landforms was clearly necessary. Previous experience of many workers (J.H. Hartshorn, personal communication) has demonstrated the excellent correspondence between landforms and surficial deposits in this region. That is, the pattern of individual deposits is a complex mosaic in which the differing topographic expression of particular kinds of material, such as sand and gravel, has been closely controlled by different processes associated with deposition. For example, kame deltas . .