316 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 19 



NEWPORT SHELF 



The narrow Newport Shelf (NE) has its shoreward end between 

 Newport Bay and Laguna Beach ; it is bounded on the west by Newport 

 canyon (Hartnian, 1963, 27) and merges oceanward and in greater depth 

 with the San Pedro slope (see Map 1 ). Sediments of the bottom are sand 

 and silt mixed with varying amounts of shelly and other biological debris. 

 Faunal diversity changes with location, depth and size of sample, as 

 shown by the following analysis: 



Most of the benthic animals of this shelf are infaunal and thus not 

 visible in surface views except as pores, small mounds or extended parts 

 of animals. Eight samples are analyzed, with three of the major groups 

 of species named on the following chart. Greater depths than 52 fms are 

 referred to the San Pedro slope area. 



1. Sta. 2745 (no. 110). 0.1 mi from end of Balboa pier, in 8 fms. 

 OPG took 0.27 cuft of gray sand and shelly fragments and numerous 

 branches of Ccllaria (bryozoans). In addition to those named on the 

 chart, Harenactis sp. (28), a nemertean (3), amphipods (45), a caprel- 

 lid ( 1 ) , cumaceans ( 14) , ostracods (5) and a small crab (6) , were pres- 

 ent. The largest species were Diopatra ornata and Chaetopterus variope- 

 datus. None was outstandingly abundant. 



Numbers of species and specimens totalled : 

 polychaetes 34 species, 77 specimens 



echinoderms 3 3 



mollusks 3 7 



crustaceans 5"^ 71 



others 4 32'' 



Total : 49+ species, 1 90+ specimens 



