ABSTRACTS AND DISCUSSIONS OF PAPERS 109 



STUDY OF RIPPLE-MARKS 

 BY WALTER A. BUCHEK * 



(Abstract) 



The mechanics of the problem ; mathematical laws ; results of new experi- 

 ments ; significance in stratigraphy ; field observations in Kentucky and Ohio. 



Presented by title in the absence of the author. 



DEAD LAKE OF THE CH1POLA RIVER, FLORIDA 

 BY E. H. SELLAEDS 



{Abstract) 



The Chipola River in Florida affords a good illustration of a tributary 

 stream ponded by the deposition of sediment in the valley of the main stream. 

 This river, which originates entirely within the coastal plain, flows for a con- 

 siderable part of its course across limestones and is fed very largely by clear 

 water limestone springs. It is therefore a clear-water stream, carrying only 

 a limited amount of sediment. The Apalachicola River, of which the Chipola 

 is a tributary, heads on the contrary in the mountains of northern Georgia 

 and receives a heavy load of sediment, which is deposited, as the river becomes 

 overloaded, near the Gulf. The Chipola enters the Apalachicola about 25 

 miles, by land, from the Gulf of Mexico. In this lower part of its course the 

 Apalachicola is rapidly aggrading its valley, while the Chipola, owing to the 

 limited amount of sediment which it carries, is building its valley much more 

 slowly. This condition results in flooding the valley of the Chipola River. 

 The lake thus formed, known as the Dead Lake of the Chipola River, derives 

 an added interest from the fact that it has come into existence so recently 

 that the cypress timber of the former river swamp, now mostly dead, is still 

 standing, although the water in the lake has reached a depth of from 10 to 20 

 feet, while the lake itself is 10 or 12 miles long and from 1 to 2 miles wide. 

 The channel of the river may still be followed in its winding course through 

 the lake. 



Presented in abstract extemporaneously. 



TECTONIC LINES IN THE HAWAIIAN ISLANDS 

 BY SIDNEY POWERS 2 



(Abstract) 



The alignment of the Hawaiian Islands shows that they have been formed 

 at the points of intersection of two sets of tectonic lines, one set running 

 parallel to the group of islands from northwest to southeast, the other set 

 being cross-fractures from northeast to southwest. On the island of Hawaii 

 the rift lines of Mauna Loa and of Kilauea ai'e quite pronounced structural 



1 Introduced by Nevin M. Fenneman. 

 3 Introduced by John E. Wolff. 



