316 Anderson — Stream Piracy of Prow and Weber Rivers. 



direction and here draining the east side of the Wasatch up 

 to Park City made the Ontario Drainage Tunnel of that 

 mining camp a possibility. The other tributary reached out 

 easterly and cut a narrow valley almost due east a distance of 

 six miies where it tapped the ancient south Fork of the Weber 

 at the south end of Rhodes Valley. The erosion bed of this 

 tributary of the Provo was about two hundred feet lower 

 (6300 elevation) than the floor of Rhodes Valley (6500 feet) at 

 the point where the small branch of the Provo tapped the 

 considerably larger stream of the South Fork of the Weber. 

 The sudden increase in gradient of the South Pork of the 

 Weber on being tapped caused it to rapidly entrench its chan- 

 nel, forming a gorge in its former valley which has extended 

 up stream about eight miles, or to about three miles east of 

 Woodland. 



It is evident that by tapping the South Branch of the Weber 

 at this point the Provo acquired about one-half of the head 

 waters of the Weber — as both forks of the Weber had ap- 

 proximately the same drainage basins and the flow of the 

 Provo was thereby practically doubled. This case of stream 

 piracy is of very recent date as the entrenching of the stolen 

 south fork of the Weber is still going on. 



Fig. 1 is a sketch map of the Coalville, Utah, quadrangle 

 showing the probable relations of the Weber and Provo River 

 Basins before the capture. Fig. 2 shows the relations of the 

 same River Basins as they are at present, after the capture. 



SCIENTIFIC INTELLIGENCE. 



I. Geology. 



1. Geological Survey of West Australia. — The activities of 

 the West Australian Survey as described in the Annual Progress 

 Report for 1913 (29 pp., 2 maps) cover a wide field with special 

 attention to economic features. " Standard " maps on a scale of 

 4 miles to the inch and " District " maps on various scales are 

 now available for approximately one-half of the country. In 

 addition to these, 93 maps of " individual " centers have been 

 published. The area of unexplored country is large and numerous 

 mining centers are active ; the time of the survey staff is therefore 

 about equally divided between reconnaissance and detailed field 

 and office studies. Preliminary papers on areas of economic 

 importance by H. P. Woodward, T. Blatchford, J. T. Jutson, H. 

 W. B. Talbot, E. deC. Clarke, F. R. Feldtmann, and C. S. Hon- 

 man, are included in the Progress Report for 1913. 



Among the interesting results of the year's work is the discovery 

 of Cretaceous fossils in the Gingin "chalk," types like the sponge 



