78 Report of the Board of Shell Fish Commissioners. 
The results of the use of the chain-wire apparatus having 
been thus plotted on the lines of soundings, the limits of the 
oyster or shell covered bottom are then shown upon the boat 
sheet by drawing a line (X-Y and M-N in figure 8) across 
the ends of the lines of soundings through the spaces which 
separate the soundings, indicating barren bottom, from those 
indicating the presence of shells or oysters. 
This line, indicating the limit of the oyster-producing bot- 
tom, does not mark the official limits of the oyster ground, but 
it serves as a guide for enclosing the ground within a straight- 
sided figure (see figure 6 on page 73) such as is designated 
shall be used to define the limits of the natural bars by 
Section 90 of the Haman Oyster Culture Law. 
FIELD AND OFFICE WORK. 
(Compiled by the Chief Hydrographie Engineer, Swepson Earle, 
from his Log-book.) 
At the beginning of the fiscal year October 1, 1907, the 
houseboat ‘Oyster’? was still anchored at Mt. Vernon, 
Wicomico River, as it was convenient to survey the oyster 
bars in Wicomico County waters to the mouth of Nanticoke 
River from that station. While at Tyaskin Station, where 
the ‘‘Oyster’? was moved October 16, the Commission decided 
to survey Worcester County waters upon the completion of 
Wicomico County and as it was not possible or practicable to — 
move the houseboat ‘‘Oyster’’ to Chincoteague Bay, prepara- 
tions were made to establish headquarters for the Shell Fish 
Commission party at Stockton, Maryland, while the Coast 
and Geodetic Survey party made arrangements to establish 
headquarters at Chincoteague Island, Virginia. The house- 
boat was towed, on November 15, 1907, to Colbourne’s Creek, 
a tributary of the Big Annemessex River and a small party 
with the launches ‘‘Canvasback’’ and ‘‘Investigator’’ com- 
pleted the buoy work of Somerset County. 
Owing to foggy weather the Coast Survey party under the 
assistant detailed by the Bureau was delayed with the triangu- 
lation in Worcester County. Hydrography of the oyster bars 
wus started November 28, 1907, and was pursued every avail- 
able day until December 18, when work was completed. To 
make the survey in Chincoteague Bay, two gasoline launches 
of very light draft were used, owing to the shoal water over 
the bars in that locality. The examinations on the bars were 
ras . ‘ e . ‘a 
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