I40 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 



will be less tlian one foot per second. These settling basins 

 are planned so as to be readily scoured through gates opening 

 to the river below the weir. 



The construction of the whole system will be substantial 

 and costly, but experience has proven this to be most eco- 

 nomical in the end. About $1,000,000 will be expended in 

 the head works portion and the canals are designed to limit 

 seepage and other losses as much as possible. 



A very troublesome matter will be the crossing of the Gila 

 River. It has been found necessary to provide for a struc- 

 ture of steel and concrete, 3,300 feet in length, to pass several 

 feet below the lowest bed of the river. It will also be neces- 

 sary to construct levees of considerable extent along the 

 reaches of the Colorado and Gila rivers. Drainage canals are 

 considered essential also, owing to the natural lay of the land. 



The cost to land owners benefited by these extensive im- 

 provements is estimated at near $35 per acre, to be paid back 

 to the Gavernment in ten equal annual installments. The 

 cost for irrigation will be about $1 per acre per annum. 



The sum of $3,000,000 is now set aside by the Secretary of 

 the Interior, upon the recommendation of the Chief Engineer 

 of the Eeclamation Service, for the installation of the Yuma 

 project. 



Fossil Peak, Santa Catalina Island. 



BY BLANCHK TRASK. 

 (Read Before the Section of Geology, Oct. 2i, 1904.) 



The fossil Pecten estrellanus Con. was found three years 

 ago on one of our greatest elevations. It appears like a 

 powder along the trail, while below, the eroded cliff-edge is 

 thick-set with the. shells from one to six inches in diameter. 



Most of them are cracked and packed in the limestone as 

 though by heavy pressure. 



An adjacent peak is topped with rolled pebbles, while the 

 great dikes of volcanic rock are visible here and there. In 

 these erosions rainbows seem to be imprisoned, and when the 

 winter rains set the emerald grasses aglow the effect is daz- 

 zling. 



In the thousands of miles I have tramped here no other 

 trace of fossils has been found. • The elevation is about 1,500 

 feet above the sea. 



