Water, sediment and periphyton samples were collected in a variety of aquatic habitats in western Montana, especially from a chain of 13 confluent lakes and ponds in the South Cold Creek Drainage of the Mission Mountains. Chemical and physical data were obtained at the site with the use of a portable test kit; associated dominant faunal and floral elements were noted; some water samples were returned for laboratory analysis, including sediment and periphyton samples. Nearly 40 species of testacea were identified. The study was successful in establishing equivalent and meaningful sampling procedures, but the data did not yield very meaningful information on the characteristics of the habitats represented. Testacea do not appear to be very useful indicators for momentary water quality. Frustules of plants may be better indicators over many years, for the arenaceous shells of some of the Testacean species decompose in sediments.