110 
The difference of density over the beds south of Little 
Island and north of Little Annemessex River is 0.0031. 
The difference of the beds south of Jane’s Island Light is 
0 . 0020 . 
These differences show that the greatest fluctuation is over 
the beds in the middle of the Sound and is probably due to 
the influence of the Big Annemessex and Manokin Rivers 
and the waters entering by Hedge’s Straits. 
Throughout the Sound there is a marked difference between 
the densities of the water taken about the latter part of Au- 
gust and the first part of September and those taken in Oc- 
tober. 
This difference is given in the following table : 
Bed. 
Date First ! 
Observat’n. II 
Date Second 
Observat’n. 1 
Difference in 
Density. 
Bed. 
Date First 
Observat’n. 
Date Second 
Observat’n. j 
Difference in | 
Density. 
"Pishinor Bay 
Aug. 
24 
Oct. 
5 
1 
.0018 
Manokin Bed 
Aug. 
27 
Sept. 
30 
.0017 
Were Point. 
24 
5 
.0014 
Harris’ Rock 
29 
Oct. 
1 
.0005 
Nanticoke Middle Gr'd. 
26 
5 
.0014 
Great Rock 
• 
30 
Sept. 
28 
.0007 
Bed N. of Turtle Egg Is. 
26 
4 
.0016 
30 
23 
.0008 
Chain Shoal 
27 
8 
.0011 
| Woman's Marsh 
.Great Thoroughfare.. . . 
Sept. 
5 
28 
.0007 
Pinny Island Rar 
28 
4 
.0010 
Cali fornia 
6 
26 
.0009 
'Johnson’s Rock 
6 
20 
0010 
It will be seen by the table that the observations were made 
at from two weeks ' to six weeks apart ; that generally speak- 
ing, the amount of difference in the densities increases with 
the interval between the observations and that the northern 
beds and those in the rivers are exposed to greater fluctuations 
of density than the neighboring ones in the Sound. 
If the change of density over the beds as shown by these 
tables, represents with approximate accuracy the change of 
salinity of the water, the fluctuation is too slight to seriously 
affect the beds or oysters but if the slightness of the change 
is due to organic matter held in solution by the waters of the 
ebb-tide, which would replace the salt of the flood, there may 
