OYSTER BEDS OF JAMES RIVER, VIRGINIA. 
13 
experience in such work is such as insured their accuracy both as 
to the area covered by the tonger and the quantity of oysters taken. 
The oysters brought in by the biological party were all examined by 
the author, who has also personally made all of the many calcula- 
tions required and directly supervised the laying off of the areas on 
the charts. The basis for the determination of the character of the 
beds was decided on in advance, but the work of the survey was so 
planned that it was impossible for any member of the party to form 
an opinion as to the conditions found until after the fieldwork was 
completed, and any involuntary prejudice was thus eliminated as far 
as possible. The author himself could form but a vague idea of the 
general results until the charts were completed and the report almost 
written. 
In the following pages the subject is gradually developed from a 
detailed description of the several parts of the individual natural 
rocks to a broad consideration of the market oyster and seed areas 
as a whole, and in every case there is given the principal data on 
which the several statements are based. 
OYSTER ROCKS. 
The term “oyster rock/’ as used in Virginia and employed in this 
report, is synonymous with natural oyster bed and is to be distin- 
guished from the term “public ground,” which is used to designate 
the areas legally embraced within surveyed lines and set apart for 
the use of the public. The public grounds were intended to embrace 
all of the oyster rocks, and usually each includes a number of the 
latter within its confines. 
An oyster rock is usually a more or less definite area of bottom, 
limited by the extent of actual oyster growth. Originally, the bound- 
aries were rather definitely marked and the rocks were separated from 
one another by barren areas, but the operations of oystering have in 
many cases strewn oysters and shells over the surrounding bottom^ 
so that in cases the original limits have become obscured and adjacent 
rocks merged. 
On the accompanying chart mucli of the bottom indicated as 
depleted really represents the areas which have been thus covered 
with scattered oysters and shells, and the term employed indicates 
that oysters and shells are very scarce rather than that they have been 
removed, though the latter is the fact in many cases. The so-called 
“depleted” areas are those on which oysters grow in quantities much 
below those which would make it commercially profitable to tong 
for them. 
The boundaries of the rocks, as shown by the red inclosing lines 
on the charts and as considered in the text, were defined by the 
