GULLIVER. — SHORELINE TOPOGRAPHY. 



221 



Figure 27. 



build.s a delta at the head of the ria or drowned valley, in adolescence it 

 pushes it well forward, and in maturity it has completely driven the sea 

 out of the valley and thus obliterated the initial shoreline of depression. 

 Bay-deltas, or ria-deltas will here be grouped under the three heads, 

 young, adolescent, and mature. 



Type Young Bay-delta : Loch Fine, Figure 27. — The type is seen in 

 loch Fine (Scot., 37) where Fine river has begun to fill the drowned 

 valley. Shira river farther 

 west has also begun to fill, and 

 later the two streams will join 

 their deltas, filling up the lower 

 portion of the ria. At the head 

 of this long bay the delta form 

 is practically free from compli- 

 cation due to sea action, which 

 in so many cases influences the 

 form of filling. 



Other Young Bay-deltas. — Many 

 occur on the northwestern coast of 

 Spain, from which locality the gen- 

 eric term " ria " was taken (Stieler, 

 33; Spain, Bol. VII, 1880, Lam. D). 



Strath Beag at the head of loch EireboU (Scot., 114). 



Loin water at the head of loch Long (Scot., 38). 



At the heads of loch Lomond (Scot., 38, 46); loch Awe (Scot., 45); loch 

 Striven (Scot., 29); loch Etive (Scot., 45) ; loch Maree (Scot., 92); loch Broom 

 (Scot., 92) ; loch Diiich (Scot, 72) ; etc. 



Tomales bay,* California, a well marked " ria," shows delta filling at its head 

 (C. S., 631). 



Drago delta, Austria (Austr., 25, IX). This stream is small, and has not yet 

 filled much of the ria, Canale di Leme. 



Type Adolescent Bay-delta : Dwamish. — The Dwamish river pushing 

 forward its delta to fill Elliott bay is the type. Seattle, built upon the 

 mainland along the margin of both the delta and the unfilled bay, has a 

 splendid combination of elevated locations for residences, flat delta land 

 for future business blocks, and a water front on deep tide water. As the 

 delta grows forward the city will occupy it, probably accelerating its 

 advance, and transfer the shipping interests farther down the bay (C. S., 

 651; G. S. Seattle). 



Young Bay -delta : Loch Fine, 

 Scotland. 



* See page 196. 



