made by polychaete worms, heart urchins, 

 and other burrowing creatures are evident 

 from holes of various sizes that extend through 

 the surface of the sediment. The number of 

 holes (average density 20 per square meter) 

 at this station is less than at Georges Bank 

 stations. 



The sediment, as judged from the photo- 

 graphs, appears to be predominantly silt and 

 of moderately dark color. This evaluation 

 corresponds closely with determinations based 

 on sediments collected with a Smith- Mclnty re 

 bottom sampler. Sediments are sandy silt, 

 dark olive green without visible shell frag- 

 ments. 



Water movements are judged to be exceed- 

 ingly weak or absent. (See section on Water 

 Movement.) 



Station 42 (Georges Bank) 



Sea bottom topography is slightly undulatory 

 with low ridges at intervals of 100 to 300 m. 

 The microtopography is disarranged and 

 uneven (fig. 4). Numerous small pockets, 



ridges, hillocks, and other irregularities occur 

 throughout the area photographed. Tracks and 

 trails of motile benthic animals are present 

 but are relatively inconspicuous owing to 

 numerous other irregularities on the sediment 

 surface. Although water movement and animal 

 tracks contributed to the uneven and disorderly 

 sea floor surface, we believe that a major 

 cause of this disturbance was the feeding and 

 hiding activities of bottom-dwelling fishes, 

 such as skates, flatfishes, haddock, and others. 

 The photographs, plus observations of 

 aquarium-held specimens of some of these 

 fishes, particularly the skates and flatfishes, 

 have shown that they habitually excavate shal- 

 low pockets and hide in the sediment with 

 only eyes or other body parts exposed. 



Burrow openings in the sediment surface 

 are common; they average 33 per square 

 meter. 



Sediment appears to be chiefly sand of 

 moderately dark color. Sediment in grab- 

 sampler collections is gray-brown sand. Frag- 

 ments of mollusk shells are common and 

 rather evenly distributed. The size of these 



Figure 4. — Sea floor at station 42, southeastern Georges Bank, water depth 66 m. Identifiable animals: A. posterior 

 end of skate, Raja ; B. sand dollar, Echlnarachnius parraa; C. ocean quahog; D. hermit crab, Pagurus . Scale bar 

 is 10 cm. long. 



