period. The purpose of the imreotigation is 'to show quantitatively the 

 relative importance of direction variability and period variability as 

 the pattern is altered by refraction„ 



SP£CI/iI DKVEIOPi^JENTS 



Repair and Rebuild Aqua-Liings 



Continued maintenaiice and i^epair of Aqua-lurigs requires approx- 

 imately 50 hours a month of shop tirae. Currently every new Aqua-lung is 

 disassembled and thoroughly checked, over before being placed in operation. 



Machine Parts for Goring De'/ice 



Miscellaneous parts were machined for a special coring device to 

 be used in the Gulf project. 



PUBLICATIONS 



Article Published 



Shepard, Francis P.^ Composite Origin ef Submarine Canyons, Jo urn. Geol., 

 Vol. 60, No, Ij, January 1952. 



Article Submitted for Publication 



inraanj, D. L. and V/, H„ Quinn^ Currents in the Surf Zone, SIO Submarine 

 Geology Report No. 23,- Froco Second Gonfo Coastal Eng, 



Mimeographed Report 



Intnan and Quinn, Cun'ents in the Sixrf Zone, SIO Reference 52-10, 1 March 

 1952. 



B , Scripps Insti tuti on of C c e anog raphy Quarterly Progress Report 

 No. 12 y April - June 19^ 



SUBMRINIi: GEOLOGY 



Seasonal Variation in Beach and Mearshore Sediments 



The study of the variation' in texture and composition of beach 

 ajid shelf sediments in the La, Jo] la area mentioned in previous progress 

 reports is being continued. The analyses of grain size distribution and 

 the mica counts have been completed. 



The study indicates that the composition of the sediments in 

 this area caxi be divided into three classes on a basis of the hydrodymaraics 

 of particle transportations \l) light minerals^ predominantly quartz but 

 including some feldspars and shell fragments^, (2) heavy mineralSj and 

 (3) xiiicaceous material which Is almost entirely biotite. The percentages 



