196 PROCEEDINGS OF THE AMERICAN ACADEMY, 



Bodega bead, California (C. S., 630), appears to be an island tied to tbe main- 

 land by a bar, probably broadened by elevation since it was built and now baving 

 its surface niucb diversified with dunes. A second bar is almost completed, a spit 

 extending from the mainland nearly across Bodega bay. Bodega head like Toma- 

 les point to the south is of resistant granite,* east of wliicli the longitudinal valley, 

 now shown by Bodega and Tomales bays, was carved in the weaker sandstones, 

 along a probable fault according to Professor Lawson. 



Point Galero, Me.xico, is tied by San Juan beacli, and a second bar enclosing Cha- 

 cahua lagoon is being built (H. O. yo-3). 



Copenhagen is ap.parently built upon a bar connecting Amager with Seeland, 

 ami the buildings and fortifications of the city have much altered tlie former ap- 

 pearance of the bar, harborage being gained by maintaining water communication 

 across tlie tombolo (Denra., KjiJbenhavn). 



Helnes island is joined by a bar at its northern end (Denm., Vissenbjerg). 

 Overlap, offset, and stream deflection all indicate a current from the riglit, so that 

 the tombolo probably grew from tiie island to tlie mainland. 



A small island south of Faaborg (Denm., Faaborg). 



Several cases along the east shore of the Cattegat (Svve., 18, 24, 32, 41, 51, 01). 



Kekenis is tied to the larger island of Alsen and tlie second tombolo is now be- 

 ginning as a spit on the other end of tiie island (Germ., '24; Denm., Faaborg). 



An island north of Gliicksburg in tiie Flensburger tjord (Germ., 23). 



Halbinsel Wustrow (Germ., 85). 



Pulitz is almost tied (Germ., 04). 



Several islands are strung together at the southeast point of Riigen island 

 (Germ., G4). 



Eye peninsula is apparently tied to Lewis island (Scot., 105), but rocky ledges 

 are shown in the tombolo, and separation may never have been complete. 



Vatersay island in the Hebrides is composed of two liigli portions connected by 

 3 lower neck (Scot., 58). 



Peninsula point, California (C. S., 5581), is tied by one bar and a second is 

 )flearly comple'fed. 



Conanicut isUnd (C. S., 353) in Narragansett bay is made up of two portions 

 joined by a b»r. 



(2) B^fh Bars completed : Monte Argentario, Figure 16. — Monte Argentario, Italy, 

 is an I'nstvuctive example in explaining the method of tying islands. 



In the interior of Orbetelio lagoon a bar extends from the mainland toward the 

 /Sidnd. This tombolo was probably the first built, from the mainland to the point 

 V(Were the village of Orbetelio now stands. Meanwhile a bar further north, Tom- 

 t)olo delln Giannella, was growing from the mouth of the Albegna river toward 

 Monte Argentario. At a little later staije shore-grade was established along the 

 southeast coast of the island and the Tombolo di FenifjUn grew toward the main- 

 land. Tiie growth of this third tombolo prevented the extension of the Orbetelio 

 tombolo. 



The reasons for the above interpretation are as follows. The tidal inlet across 

 the Tombolo della Giannella is close to the island while that of the Tombolo di 

 Feniglia is next to the mainland. With such simple bars as these are, where there 



» J. D. Whitney, Geol. Sur. Cal., 1866, I. 84, 85. 



