John Macculloch, who was the first geologist to describe the Island of Rum, was so perplexed by the geological relations of the lavas of this island, that he wrote— “It is fruitless to accumulate conjectures, but it is not useless to confess ignorance, since it will point out to other travellers the blanks to be filled, and the errors to be corrected; while I may state in the words of St. Augustin my conviction that in this science also ‘Melius est dubitare de occultis quam litigare de incertis’. [It is better to doubt about mysteries than to dispute about uncertainties.]” (Macculloch, 1819, i, 497.) In spite of this self-imposed limitation Macculloch quite correctly compared the “stratified traps” of Rum with those of Skye and Canna, but otherwise he did little towards the description of these rocks.