The thesis is an attempt to apply procedures of descriptive linguistic analysis to a body of material phonetically transcribed by Leo J. Frachtenberg in the Mary's River dialect of the central Kalapuyan language. In 1913-14 Frachtenberg collected thirteen volumes of myth texts in Mary's River, twelve from William Hartless and one from Grace Wheeler; in addition, there were notes to the texts, three volumes of grammatical notes, and some ethnographic material. The phonetic transcription was carried out in the pre- phonemic tradition of recording everything the speaker said as accurately as possible. There was no attempt to elicit forms in a manner which would establish which sounds were "the same" to the speaker, resulting in a considerable proliferation of variations of forms. The main methodological problem, therefore, has been to sort out phonetic variation and phonemic contrast. This task was more difficult because no complete morphemic analysis exists as yet, so that morphophonemic alternations created additional complications. My method consisted first of tallying the forms that occurred, to establish those variants found most frequently (modal forms). The modal forms were examined to discover patterns of contrast and complementary distribution; those variants of forms which were not modally distributed, and single examples, were then compared to help confirm or modify the emerging phonemic patterns. I arrived at a system of 21 consonants, six vowels, four diphthongs, and phonemic stress. This includes two obstruent series, glottalized and unglottalized, five fricatives, three resonants; and two glides. The vowels are high to mid front, low center, and high to mid back, with length distinctive. One pair of diphthongs is also distinguished by length; the others involve non-phonemic length. Consonant clusters are limited to two members initially and finally. A number of uncertainties remain. These include the behavior of glottal stops and aspiration in final and medial position, the variation in vowel length, the distribution of velars, the distribution of diphthongs, and the relationships between /w/ and / u / , /y/ and /i/, and /f/ and /w/. These may be clarified when the morphemic analysis is complete. The phonemic system appears to resemble most closely that of the neighboring Molala, although the lexicon and grammar show only slight similarities; the related Takelma also seems quite similar phonologically. Since phonological features can be borrowed by one language from another, and in the Northwest frequently have been, further examination of such resemblances may shed light on former historical contacts between Kalapuyan speakers and other groups.