38 



about as a result of the changes m the draiiiaye that followed 

 the inakiug' of the cut-otf into Lake Barre, and the deepening 

 of the upper part of Bayou La Graisse. At the lower end of 

 this shallow portion of the bayou there are some small natural 

 reefs, but apparently the deposition of the mud is still going 

 on so rapidly that these reefs are being covered up faster than 

 they are increasing in height, so that their disappearance is only 

 a ciuestion of time. Below this filled-up portion the depth of the 

 water is about twelve feet for some three miles or more. All 

 along this portion of the bayou the bottom is covered with shells 

 and is unusually hard. In some scattered spots there are a few 

 good oysters on the old reefs, but they are not of sufficient abund- 

 ance to be of an}^ commercial importance. A very deep place in 

 the bayou at the entrance to a pass on the south side marks the 

 lower limit of the hard bottom. Below this pass the bayou is 

 deep for some three-quarters of a mile to a point where there is 

 a pass on each side of the bayou. Below these passes the bayou 

 is shallow and the bottom is composed of very soft mud. 



Below the pass to Bay La Graisse the salinity of the water 

 v/as 1.0158, and showed no effect from the flow of fresh water 

 farther up in the bayou. In fact, for the purposes of oyster cul- 

 ture, the portion of Terrebonne Bayou below Bayou La Graisse, 

 may be considered as a separate body of water since it receives 

 the greater part of its water through the passes from Lake Barre 

 and the passes from the bays on the south side. 



On the south side of Terrebonne Bayou, to the east of Bay 

 La Graisse, there are several large bays that have passes to this 

 ba^you at their upper ends, while below they open into Cat Island 

 Lake or Timbalier Bay. 



Bay Jean Pierre, the farthest west of these bays, is some 

 three miles long and one and one-half miles mide. The depth 

 of the water varies from three to eight feet in ditt'erent parts of 

 the bay. The bottom is composed of soft mud except where there 

 have been old oyster reefs. The old reefs are especially numerous 

 in this bay, so that the hardened areas make up a considerable 

 portion of the whole area. In the northeastern part of the bay 

 there is a large dead reef that extends for at least a mile in an 

 east and west direction, and is from 100 to 150 vai"ds wide. 



