GULLIVER. — SHORELINE TOPOCxRAPHY. 193 



Another cuspate foreland projects from Taransoy island toward Harris island 

 (Scot., 98). 



Vigso island has two curved spits not quite able to reach the mainland (Denni , 

 SaxkjiJbing). 



c. Attached to Mainland and Island : Aebelo ; Figure 13. — A bar is forming from 

 Aebelo island and from a smaller island close to the mainland (Denni., Bogense). 



Another example is Spectacle island in Boston harbor (C. S., 337), where the 

 "nose-piece" of the spectacles consists of two cusps almost joined. Upon the 

 Coast Survey chart these two islands are not joined, but in 1896 the writer saw 

 from a steamer that the tombolo was completed. 



Between Pabbay and Berneray islands a tombolo has begun to grow which con- 

 sists so far of a cuspate projection from each island (Scot., 89). 



The tombolo connecting North rocks with the Irish coast (Ireland, 49, 50) is not 

 completed, and it is very probable tliat these rocks will be completely consumed 

 before tying on is accomplished. 



The flats between Barra and Fiaray islands represent the attempt of the sea to 

 tie islands together (Scot., 58, 59, 68, 69). The flats surround three other islands. 



Tombolo growth is indicated from both Ibiza and Formentera islands, the ad- 

 vance from each island being made toward the other (Spain, Bol. VII, Lam. B). 

 There are several small islands in the line of probable future growth, which will 

 be surrounded by the completed tombolo. 



Marrowstone island, Washington, at present is detached from the peninsula to 

 the west, Kilisu harbor having communication across the bars at both its north- 

 ern and southern ends (C. S., 64.50 and 647). 



Several of the islands in Sitka harbor, Alaska, are soon geographically to be- 

 come land-tied ; as, for example. Cannon island, Beardslee islands, and The Twins 

 (C. S., 725). 



Isia de Apics, Mexico (H. O., 878), is now connected at low water. 



Rush and Ackerman islands, Costa Rica, are nearly in this stage (11. 0. 1028). 



Redonda and Siriba islands, Brazil (H. O., 486). 



A tombolo largely of mechanical construction though there is some coral growth 

 in it, is attempting to connect Ceylon with the mainland.* 



IV. Completed Tomholo (Adolescence). — As a rule when islands along 

 a stretch of coast are completely tied to the mainland by tombolos, the 

 coast as a whole is graded, and may he regarded as in adolescence. Oc- 

 casional youthful features will persist after the region has reached adol- 

 escence, and in the same way completed tombolos will sometimes be found 

 where the other features of the coast are indicative of youth. There 

 are three classes of tombolos : single, Y-shaped, and double. 



a. Single Tombolo : Nahant, Figure 14. — Nahant is tied to the Massachusetts coast 

 at Lynn by a single tombolo, which is typical, with the exception that the island 

 itself is made up of Big and Little Nahant, which are themselves joined by a 

 tombolo. 



* Map by J. Walther, Pet. Geog. Mitt., Erg. 102, 1891. 

 VOL. XXXIV. — 13 



