Towards the end of last winter session, a Memoir by me, on the “Parallel Roads of Lochaber,” was read to this Society, and it has since been published in our Transactions. The subject was far from being exhausted. Nevertheless, I had no intention of continuing the inquiry, venturing to think, that enough had been adduced by me to support the conclusions at which I had arrived. But during the course of last summer, Dr Tyndall of London visited Lochaber. He went for the special purpose of studying the “Roads,” and of enabling him to give a public lecture regarding them in the Royal Institution, Albemarle Street, on 9th June.
In the course of his lecture, Dr Tyndall alluded to my recent Memoir, and also to researches described in a previous Memoir. But he dissented from my solution of the problem, and told his hearers (I quote his words) that they might “with safety dismiss it (the detrital barrier theory) as incompetent to account for the phenomena. The theory which ascribes the Parallel Roads to lakes clammed by barriers of ice, has, in my opinion, an amount of probability on its side, which amounts to a practical demonstration of its truth.”
These views having been rested on observations made in the district by Dr Tyndall himself, I felt that it was only due to a person of his scientific reputation, to reconsider my own opinions, and to weigh well his reasons for coming to a different conclusion.