Report of the Board of Shell Fish Commissioners. 37 
lying bottoms are not just as favorable for the growth of 
oysters as those which prevail on the bottoms in shallower 
water. Depths of water from 50 to 60 feet were frequently 
found in the course of the survey over productive natural 
oyster grounds in the part of the river below the mouth of 
St. Leonards Creek. Above St. Leonards Creek the depths 
of water over the outer limits of the bars range from 20 to 
45 feet. 
A satisfactory report on the kind of bottom found to form 
the basis upon which the natural oyster bars have been de- 
veloped in the Patuxent River would require a separate de- 
scription for each bar, but the records of the chain-wire read- 
ings, soundings and examinations indicate that, as a rule, hard 
sand forms the bottom between the shore line and the ten- 
foot depth curve on both sides of the river; that soft mud 
occupies the middle of the river to about the twenty-foot 
depth curves on either side, and that the bottoms between the 
ten and twenty-foot curves is composed of sand and mud 
mixed in such proportions as to produce a sticky surface 
sufficiently firm to support oysters and shells at its surface. 
Exceptions to this rule are to be found at several places, in 
which very soft bottoms occur in shallow water near shore, 
especially in the part of the river above Sheridans Point. 
The bottoms in the very deep water in the vicinity of Point 
Patience are very hard. ’ 
Oyster planting operations will no doubt be confined at first 
to the bottoms near shore where oysters once grew naturally 
but the bottom, even in the middle of the river, can without 
great expense be made suitable for oyster planting and much 
of it will ultimately be taken up and used for that purpose. 
A gradual increase in the density of the water took place 
in the Patuxent during the period occupied by the survey 
(June 2-September 2, 1908), a phenomenon which doubtless 
takes place at a corresponding time each year, a decrease 
taking place each spring. The unusually severe drought of 
the summer of 1908 makes it probable that densities as high 
as those observed over the oyster grounds in the upper part 
of the river are not usual during corresponding seasons of 
other years. The following table gives the range of densities 
observed over the oyster bars in four sections of the river, 
the maximum and minimum densities observed at each place 
being given with the dates of the observations. A very con- 
siderable daily fluctuation in the density of the water in each 
