T.M. No. 19 - July 1950 



Submarine Topography and Sedimentation in the Vicinity of Mugu 

 Submarine Canyon, California by D. L. tnman 



The bathymetry of the adjacent shelf and the submarine canyon 



heads adjacent to the beach and lagoon is described. Mugu Submarine 



Canyon has two branches at its head, each having an isolated ridge 



protruding from the floor parallel to the canyon axis. The relation 



of sediment type and bottom topography is investigated. 



T.M. No. 20 - July 1950 



Beach Cycles in Southern California by Francis P. Shepard 



From a mass of records and data accumulated on California beaches 

 salient features observed are discussed and their interpretation 

 attempted. Features discussed include seasonal changes both offshore- 

 onshore and lateral movement, long-term trends, changes associated 

 with engineering structures, and relationship of permanent and 

 temporary losses. 



T.M. No. 21 - November 1950 



The Interpretation of Crossed Orthogonals in Wave Refraction Phenomena 

 by Willard J. Pierson, Jr. 



The theory of wave refraction is critically reviewed. Analytical 

 examples of caustic curves are given, and it is shown that refraction 

 theory, as based upon geometrical optics, fails at the caustfc. More 

 refined techniques lead to the result that there is a phase shift 

 through the caustic and that waves remain finite in height; possible 

 solutions are discussed. Results of other investigators are applied to 

 a model study of refraction of waves over a clock glass, and the 180- 

 degree phase shift through a caustic is demonstrated. The orthogonal 

 method of refraction analysis is applied for Long Branch, New Jersey, 

 and caustic curves and overlapping wave trains are found. More accurate 

 techniques for use after a sufficient number of orthogonals have been 

 constructed are described, and evidence is given confirming theoretical 

 deductions. tt is shown that further theoretical and practical studies 

 are needed, and specific suggestions for future research are given. 



T.M. No. 22 - March 1951 



The Source, Transportation, and Deposition of Beach Sediment in 

 Southern California by John W. Handin 



Detailed description of beaches and coastal physiography from 

 Carpinteria to Point Fermin, California is presented. Submarine 

 geology and wind and wave forces are given. Petrographic analysis of 

 beach, stream, and dune sands is presented; sources of beach sediments 

 are discussed. Discussion of transportation and deposition of beach 

 sands (littoral drift) is presented. 



