On the Lines of Deepest Water around the British Isles

Abstract

From two papers by Mr. Godwin-Austen we learn that the English Channel was, in all probability, a valley of depression. If, by the light thus afforded us, we examine the locality as laid down in a good chart, we shall see that as there is a valley of depression, so is there also an axis of depression, if the term may be used. We have in common use the term “axis of elevation” to signify the line of greatest elevation in a mountain-range; and in a similar way we would employ the phrase “axis of depression” to mean the line of deepest water in a narrow sea. If we take a point (see Map) nearly south of Dungeness in Kent, or in north lat. about 50° 30′, and east long. rather less than 1° and from this draw a straight line a little to the south of west, passing through the middle of the deep water, and meeting about north lat. 48° 20′, and west long. 8° 20′, and another line of a similar kind passing through the deepest water of the St. George's Channel between Ireland and England, we find, tracing the course of our line, that it first passes between the two pits, called “North Deep” and “South Deep,” in the same longitudinal or axial direction as both of them; it cuts the “fWest Deep” in its deepest part, and nearly in the same longitudinal direction; it passes through the “Hurds Dyke” from end to end, and meets