8 OYSTER BOTTOMS IN MATAGORDA BAY. 



and more important beds were developed by stations taken at inter- 

 vals of about 200 yards around their margins, which gives consider- 

 able accuracy of delineation. In the cases of most of the smaller or 

 scattering beds, however, this was considered unnecessary, and the 

 actual shape and area of these may therefore vary slightly from that 

 shown on the chart. The error in any case is not material. 



The lines of the primary series of soundings were made from 

 launches running at a speed of 4 miles per hour, soundings being re- 

 corded at fifteen-second intervals, and the position of the boat being 

 fixed every five minutes by three-point sextant observations. The 

 individual recorded soundings were therefore about 30 yards apart, 

 and the positions of the boat were fixed at 600-yard intervals. 

 The lines were run on ranges or on courses and bearings, flags erected 

 on shore or in the bay being used as marks to insure accuracy of 

 direction. In that part of the bay above Kains Landing, where small 

 beds and scattered growths are numerous and not all well known to 

 the oystermen, the lines were 300 yards apart, but below there they 

 were gradually opened out until in the region between Dog Island 

 Reef and Half Moon Reef, where the beds are few, large, and con- 

 spicuous, they were run at intervals of 800 yards. The sounding pole 

 devised by Lieutenant Swift for his work in Apalachicola Bay a was 

 used continuously while the boats were under way, and in addition a 

 chain was dragged from the launch so as to give a practically contin- 

 uous report of the character of the bottom and the presence or absence 

 of oysters. The chain was rigged from the bow of the launch on a 

 small boom so as to keep it clear of the propeller, a lanyard running 

 inboard to the helmsman, who instantly felt the surge of the appa- 

 ratus as it came in contact with oysters or shells, and reported the 

 occurrence at once to the recorder. 



The zigzag lines in the shoal water inshore were run from a flat- 

 boat, the methods of sounding being practically the same as those 

 used on the launches. The nature of the bottom in general was 

 observed by means of the sounding rod, supplemented at intervals by 

 probings with an iron rod to determine the character of the sub- 

 stratum. The examinations of the oysters were carried on inde- 

 pendently of the soundings, thus saving the sounding party the an- 

 noying interruptions commonly experienced in work of this charac- 

 ter. The plan adopted was a distinct gain in speed and accuracy. 

 When the sounding pole or chain indicated a bed of any importance, 

 the officer in charge of the sounding party, usually without stopping 

 the boat, erected a flag flying the number of the nearest sextant sta- 

 tion, noting the exact time in the sounding book. From these data 



a Report of a survey of the oyster regions of St. Vincent Sound, Apalachicola 

 Bay, and St. George Sound, Florida, by Franklin Swift. Rept. U. S. Fish Com. 

 1896 (1897), p. 191. 



