212 PROCEEDINGS OP THE AMERICAN ACADEMY. 



lough Foyle from near the tip of Magilligan point, and its straightness 

 and length suggest a fairly constant and strong tidal current through the 

 inlet, three fourths of a mile broad, between the point and the right side 

 of the bay. 



This foreland has the cuspate outline appropriate to a tidal cusp, but 

 on the bay side it shows no line of growth. Back of the present ocean 

 beach, however, are seventeen roads which curve sympathetically witli 

 the shoreline of to-day. These roads are not parallel lines, but each 

 curve is nearly parallel with the two on either side, departing just enough 

 from parallelism to make a systematic series, changing gradually from a 

 direction a few points south of west to one nearly northwest and south- 

 east. Between almost every pair of adjacent roads is a ditch, whose 

 course is systematically accordant with the direction of the roads. These 

 culture lines are not constructed in a haphazard manner, and their orderly 

 arrangement suggests a series of successive curves of higher and lower 

 ground. Such a systematic series indicates lines of growth. If this 

 indication be true, then this cuspate bay-bar began some five miles farther 

 up the bay. and has advanced by some seventeen steps to its present 

 position. 



As said above, the bay side or right side of the cuspate bay-bar shows 

 no airirradational line of growth. Each of the roads and ditches ends 

 at the liigh tide line, forming transverse features in respect to the bay 

 shoreline, while the same are longitudinal with respect to the ocean 

 shoreline. This abrupt ending, together with the continuous curve of 

 the bay shoreline, suggests that the sea may have shaved off the ends of 

 these presumable former beaches. 



As confirming the above hypothesis for the formation of Magilligan 

 point, it is observed that the cliffs, some 200 feet high, where the along- 

 shore action changes from cutting to aggrading, continue as a nip behind 

 the Magilligan foreland. This cliff is progressively lower toward the 

 supposed earlier formed portion of the foreland. This would be expected, 

 since the portion of the cliff which was exposed for a shorter time to sea 

 action, other thiniis being equal, would have the less height. 



The dominant current from the right, which is indicated by the form 

 of this bay-bar, is possibly due to a backset eddy between Islay island 

 and Ireland. The ocean current flowing from the southwest along the 

 west coast of the Britiah islands * could cause such a backset eddy in 

 this locality. 



* Eriimmel, Uebersichtskarte der Meeresstromungen, 1886. 



