20 



is supported by the evidence of the sounding pole and probe. East of the northern part of the 

 bed, in the channel, are two small shoals with 12 feet of water on them. On and around them 

 small oyster beds have formed, and between the shoals and the main bed oysters are found scat- 

 tered in groups in water as deep as 8 fathoms. On the main bed the bottom is a thin stratum ot 

 oysters and shells resting on mud or sand. East of the bed soft blue mud was found, and to the 

 westward mud, shells, and sand. The oysters were large, sinjjle, and in small clusters, and of good 

 quality; the largest oysters were found on the soft muddy bottoms; the number of young growth 

 was smaller than on the beds previously described, while the number of young was larger; a few 

 drills were found about the edges of the bed and a moderate amount of red sponge. On the small 

 beds in the channel the oysters were principally of recent growth. East of those beds a good deal 

 of grass was found, and also in the deep water between the shoals and main bed. 



Chain Shoal Bed. — This bed lies on the eastern side of the channel, abreast the Lower Thor- 

 oughfare and Little Island. It extends north and south li miles, is from one-eighth to three eighths 

 of a mile wide, and comprises an area of 1,192,000 square yards. It is unbroken, except about its 

 western border, where the oysters are found in groups; to the eastward the sands, on which are 

 scattered a few single oysters, (dearly define the limit of the bed in that direction. The bottom is 

 irregular, the depth of water being from 12 to 1!) feet, and the upper stratum consisted of shells, 

 oysters, and mud; the substratum was of hard sand. The surface stratum was from 1 foot to 4 

 feet thick, and, with a diminished amount of sand, increased in thickness on the southern part of 

 the bed. The surrounding bottoms are of sand, though on the western side the mud of the chan 

 nel approaches the bed closelj r . The oysters were of moderate size and fair quality. The mature 

 oysters were single; those of recent growth, a large number of which were found, were single 

 and in clusters, the latter predominating. Very few young were discovered, and very few drills 

 (aslyrix); the latter. were located principally on the southern part of the bed. A large amount of 

 red and gray sponge was found on all parts of the bed. The oysters- on the contiguous bottoms 

 were similar to those described on the bed. 



The Muscle Hole Bed. — This bed lies on the western side of the channel, south of the Mud 

 Rock. It extends north and south about 3 miles, is from one half to one-quarter of a mile wide, 

 and comprises an area of 3,000,000 square yards. It is very irregular in suape, and at about two- 

 thirds of its length to the southward it is cut in two by a mud slough. The depth of water is 

 from 12 to 34 feet, and the bottom very irregular, especially about the northern portion, which is 

 cut up into shoals of shells and oysters separated and intersected by narrow mud sloughs, over 

 which the oysters are thinly spread. About the central portion the middle of the bed is compara- 

 tively solid, but the eastern and western portions are similar to the northern. The southern part 

 is also broken up considerably, but the bottom is not as irregular as elsewhere. The bottom con- 

 sists of a stratum of oysters and shells mixed with mud anil sand, from one-half foot to 2 feet in 

 thickness, resting on a stratum of hard sand. The shell stratum was thicker along the western 

 part of the bed, where the dark line is drawn on the chart, and decreased in thickness as the 

 eastern edge was approached, where it was hardly observable, and where a substratum of mud 

 was frequently found. East of the bed the bottom is soft mud; to the westward soft sand or 

 sticky mud, with usually a hard substratum. The mature oysters were large and single and of 

 good quality. A very large proportion of young growth was noticed, at least one-half the oysters 

 being of that description. A large number of young, but few drills (astyrifs), were found on the 

 hard bottoms of the central part of the northern portion. On the central and southern portions of 

 the bed the number both of young and drills decreased, while they increased greatly ou the west- 

 ern portion. A large amount of red sponge was found, and in greater quantities about the edges 

 of the bed, especially the western, than elsewhere, but its presence appeared to have no effect 

 upon the young or drills. East of the bed the oysters were of the same general character as those 

 on it; the same proportion of young growth was also noticed, but there was almost an entire 

 absence of young and drills. To the westward, as a rule, the oysters were somewhat larger than 

 those on the bed, but as many young growth were present as elsewhere. The number of young and 

 drills was, however, much diminished, as was also the amount of red sponge. The number of oysters 

 to the square yard, the mean of thirty six observations, was 0.70. The number to the square yard 

 on the area occupied by scattered oysters, the mean of seventeen observations, was 0.07. 



