Abstract

In a paper on the “Origin of the Parallel Roads of Glen Roy,” read before the Society and published in the Quarterly Journal for August 1869, I described some physical facts which appeared to me to place their marine origin beyond doubt. So far. as I am aware, no attempt has been made to answer that argument.

But I have been asked “to explain the extraordinary coincidence of the sea-level with five (four) successive cols.” It has been further asked how, if the same sea filled Glen Roy and Glen Gloy, it formed a road in the latter and none in the former glen; why are the lines of partial occurrence even in this region—the highest limited to Glen Gloy, the second and third almost to Glen Roy, whilst the fourth extends round both Glen Roy and Glen Spean? If all the time the same sea filled all these glens, and was liable to the same oscillations of level, why has it formed roads in one or two of them only, not in all? Why are not the second and third roads as well seen in Glen Spean as in Glen Roy, and the Glen-Gloy line not in one only but in all the three? These questions plainly need to be answered; and the answer, in my opinion, forms the key to the whole of the phenomena.

Facts stated in my former paper proved that, shortly before the formation of the roads, this part of Scotland was submerged in the