[183]

The longitudinal furrows on mountains well explained in my Glen Roy paper – a flat bottomed cove if suddenly elevated would not be produced downwards – a tidal channel (aided probably by first cause which made cove) giving entrance to sea, which would then act on same principle, it widens a parallel sided fissure, [sketch] the action of sea being confined to beach – Lines A & B, however must converge because power will diminish from protection – The downward prolongated

[183v]

of the cove at one level will be slightly aided by the quantity of matter above being less to remain in (2) then in (1), that is if sea coast ever occupies the line O. P. the difference will be [triangular] A, B, C & by so much more will section (2) drawn through valley be prolonged.

[diagrams]