The dating of Shelley's prose essays and fragments is at present very uncertain. Mary Shelley's dates in the preface to Essays, Letters from Abroad, Translations, and Fragments, 1840, are, for the most part, conjectures. W. M. Rossetti in A Memoir of Shelley gives briefly, without systematic evidence, the dates of some of the fragments. Forman and the Julian editors follow, with some exceptions, Rossetti's dating in their editions of Shelley's prose. Koszul laid a more secure foundation for the dating of some of Shelley's prose. His study of the external evidence of the MSS in the Bodleian notebook has resulted in considerable progress. The present writer has approached the problem of dating Shelley's prose from a study of the internal evidence which consists, in a large measure, of the study of the relation of Shelley's prose to his reading as found in the Journal of Shelley and Mary, Shelley's letters, and other biographical sources. Shelley's quotations, references, and allusions to his reading supply valuable information for dating. Some of the prose fragments, hitherto undated, are assigned a date, while the date of others is changed, confirmed, or given more precise limits. It should be acknowledged, however, that Shelley's wide variety of reading, and the extraordinary tenacity of his memory make for caution in dating works too confidently on the basis of internal evidence. Until such time as Shelley's prose MSS are studied as minutely, thoroughly, and systematically as the MSS of the Bodleian notebook, the dates of the fragments given in the following notes may serve as tentative points d'appui for a study of the development of Shflley's thought.