574 PROCEEDINGS OF THE AMERICAN ACADEMY. 



algae and molluscan remains, with about 10 per cent of fine calcareous 

 silt. Further south, east of Boaz Island and Somerset Island, in a 

 depth of about four fathoms, the appearance of the bottom is altered 

 by the complete absence of coral patches or ledges, although there is still 

 a small amount of living, and a good deal of dead, coral. The bottom 

 samples here consist of white sand, in which fine and coarse material are 

 in about equal amount. The former is about 60 per cent calcareous silt 

 or marl, the remainder being calcareous spicules, together with a great 

 variety of small organic particles. The coarse material consists chiefly 

 of algae, millepores, molluscan fragments, and living mollusks, with worm 

 tubes and echinoid plates. There are very few Foraminifera and few 

 coral remains, although there are a considerable number of millepore 

 fragments. As we go still further southward into the sound, we find the 

 bottom near its southern edge in ten fathoms, composed of sticky white 

 sand of similar constitution but containing a much larger proportion of 

 fine ooze. Apparently this deep basin is a region of deposition for the 

 silt collected by the water on the outer flats. 



On the south and east sides of Great Sound, between the different 

 islands, there are several shoal bars where the sand is sufficiently dis- 

 tinctive to be worth special notice. On the bar between Tucker's and 

 Morgan's islands, which forms the southern boundary of Great Sound 

 and the northern boundary of Little Sound (Station 458), in three fathoms, 

 the bottom is whitish, thickly mottled with bright yellow, rather coarse, 

 granular, clean sand, with 6 per cent fine ooze. The yellow color is 

 due to a staining of many of the fragments. Large Foraminifera, of 

 the same genera as those found in Castle Harbor, together with their 

 casts, form about 20 per cent ; calcareous algae, bivalves, and gasteropods, 

 60 per cent; the remainder being composed of Serpula, echinoid spines 

 and plates, millepore, and coral. There are many living Foraminifera 

 and mollusks in this bottom. 



The same type of sand, of the same yellow color and with many liv- 

 ing mollusks, forms the bars between Godet Island and the main island 

 (Stations 463 and 464), and between Moses and Darrell islands (Stations 

 456 and 457) on the east of Little Sound ; it also forms the bottom olT 

 the north and west sides of Elizabeth Island (Stations 455 and 456). 

 But in the channel leading into Hamilton Harbor (Station 421), the 

 sand, though yellowish and almost free from ooze, is much finer, con- 

 tains very few living organisms, and consists chiefly of water-worn frag- 

 ments of algae, mollusks, and millepores. It is probably an area for 

 deposition of material from the surrounding shores and shoal bars ; but 

 all the finer detritus is scoured out by the tide. 



