Robert Jameson is generally remembered for championing Neptunist geology (originated by Abraham Werner) during its early 19th century competition with the rival Plutonist theory (initiated by James Hutton). Hutton's ideas prevailed, and Jameson's intellectual transition to Plutonism is documented in the surviving notes taken by students who attended his lectures at Edinburgh University: one early record is from 1809, a second record is from c.1820, and four sets of notes are from the early 1830s. Of the latter four, two have not been previously considered from a geological perspective and prove to be the most revelatory of Jameson's conversion; notes compiled by the Royal Navy surgeon Robert McCormick are particularly comprehensive. Although Jameson attempted to maintain the essentials of Werner's theory for its well-ordered stratigraphy, he progressively adopted a Plutonist approach to more contentious issues such as the origin of granite, veining, and mountain building. Jameson used Edinburgh's Salisbury Crags sill for field demonstrations and the students’ notes illustrate his changing views in terms of the origins of this classic geological feature. Of the students whose lecture notes survive, it is only McCormick for whom Jameson appears to have been a lasting geological influence.