. Bulletin of the Geological Society of America. Geology. 420 F. P. GULLIVERâCUSPATE FORELANDS. if it were not for the river there would not be any cusp here, as there is no projecting point in the okUancI to cause eddies in the currents. The evi- dence from the turning of the mouths of the small streams both to right and left indicates that the direc- tion of current motion alongshore is probabl}'' sometimes in one di- rection and sometimes in the re- verse. The smaller streams on each side of the river mouth are deflected away from the point of the cusp, indicating that the delta mass divide
. Bulletin of the Geological Society of America. Geology. 420 F. P. GULLIVERâCUSPATE FORELANDS. if it were not for the river there would not be any cusp here, as there is no projecting point in the okUancI to cause eddies in the currents. The evi- dence from the turning of the mouths of the small streams both to right and left indicates that the direc- tion of current motion alongshore is probabl}'' sometimes in one di- rection and sometimes in the re- verse. The smaller streams on each side of the river mouth are deflected away from the point of the cusp, indicating that the delta mass divided an on-shore current and turned it to the right and left, carrying the river sediment from the river along the shore. Further from the river, both on tlie right and left sides, there are streams deflected toward tlie mouth of the main stream. There is here evi- dently no dominant movement in either direction alongshore. A former stage of the delta is indicated by the ridge of geolog- ically older material, which is represented in the figure by the broken line. This earlier stage of the delta front is seen to liave a rounded outline. This suggests that formerly tliere was a domi- nant movement alongshore. Back of this former shon.'line are seen f .... ,^... â ;^ '^ ares of marsh, filled lagoons, or v\oxiv.^ delta ciispaic i-urciand. lowhiud bchiud the old bcach. Since this leap from some still earlier i)Osition of the shoreline, the for- ward growth seems to have been gradual, for no long slashes of swamp are shown. From map inspection this delta cannot be definitely referred to either of these hypotheses of origin, for it combines features of both the first and the second. This type is the Tiber (Ital., 149; Carta Geologica della Campagna Romana, Roma, 1888). It has been turned from the usually desirable north and south orientation parallel to the sides of the page in order to. Y^Llonxetre^. Please note that these images are extracted from scanned page images that ma
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