GULLIVER. — SHORELINE TOPOGRAPHY. 229 



gradual, for no long slashes of swamp are shown. This type is the Tiber (Ital., 

 149; Carta Geologica della Campagna Romana, Roma, 1888). 



The Angitola delta (Ital., 241) extends a small cuspate point beyond the curve 

 of the bay-bar, as if the stream crossing the bar was relatively strong enough to 

 divide the alongshore current. It has been found impossible to pick out from the 

 other examples of cuspate deltas given below, any which were later stages of this 

 embryonic type. The maps give little more than the form of the latest stage of 

 development. Tiie forms should be studied on the ground, in order to see what 

 was the embryonic condition. This study is analogous with what is done by the 

 paleontologist when he peels ofE the outer shell of an Ammonite in order to dis- 

 cover its embryonic form. 



In both the Biferno (Ital., 155) and the Ofanto rivers (Ital, 165) the deflections 

 indicate a current from the right at present, though formerly the deflection was in 

 the opposite direction, according to the indications from inland form. 



In the two following examples of deltas, Volturno (Ital., 171, 172, 184) and Om- 

 brone (Ita)., 127, 128, 135), the streams are deflected in both directions, thus indi- 

 cating no dominant current alongshore. 



The current is probably from the left in front of Alento delta (Ital., 141) and 

 from the right at Neto delta (Ital., 238). 



Diina river (Hus., 13) has a cuspate foreland projecting into the Gulf of Riga. 

 The deflection of the Aa river to the left indicates a strong current from the right 

 at the head of this gulf. 



The Aa de Livonie, east of the Diina, also has a cuspate outline (Rus., 13). 



Punta Arenas, a Chilean settlement. South America, is built on a foreland made 

 by combined action of river and sea (H. O., 450a). Deflection is to the left. 



A variation from the typical form is seen in the hooked j)oint of A usable delta 

 in Lake Champlain (C. S., 554 ; G. S., Plattsburg, N. Y.). 



In the Voistrap at Aaeby (Denn)., Frederikshavn) the southward deflection of 

 the mouth indicates a prevailing current from the right. 



The Danzig mouth of the Vistula (Germ., 70) shows deflection to the right. 



Kolberg is built on the cuspate delta of the Persante (Germ., 98). The evidence 

 along this coast is for a current from the right. 



Many of the discharge sluices emptying into the Zuyder Zee have built cuspate 

 deltas, and though aided by artificial means, the form is so typically cuspate that 

 they are included in this category (Holl., 15, 16, 21, 26, 27, 32). 



4. Rounded Deltas. — The type of this class of deltas is that of the Arno (Ital., 

 104, 111). The delta front is bounded by a curve convex seaward, changing into 

 the shore curves concave seaward. In contrast with the case of the Tiber the river 

 is here not strong enough to separate the alongshore current into two eddies. The 

 current swings around the delta, and gives it a smoothed outline in place of 

 a cuspate. 



Fortore delta, Italy (Ital., 155). This sheet shows a portion of the former 

 channel, fiume morto, on the left wing of the delta. 



The Sinni, Agri, and Basento deltas (Ital., 212, 201). Dominant current from 

 left. 



The Sele delta, Italy (Ital., 197, 198). Dominant current from right. 



Sangro and Trigno deltas, Italy (Ital., 148). Currents uncertain. 



Vomano, Saline, and Pescara deltas, Italy (Ital., 141). Dominant current from 

 right. 



