9 



REPORT OF THE INVESTIGATION CONDUCTED DURING THE SUMMER OF 1878. 



My subordinates and assistants during the season were Master H. H. Barroll, U. S. N"., and 

 Mr. S. E. Stevens. Mr. Barroll tested the water specimens, 475 in number, and corrected the 

 hydrometer readings for temperature; and compiled and arranged the record books and the various 

 tables appended and referred to in the report. Mr. Stevens assisted in plotting the work, calcu- 

 lated the areas of the beds and of the bottom covered by scattered oysters, and developed the pro- 

 files of the bottom. 



OYSTER BEDS OF THE JAMES RIVER, VIRGINIA. 



The examination of these beds was a very hurried one, and the delineation must be regarded 

 as merely approximate, being the result of a hasty reconnaissance. On that account no attempt 

 has been made to produce a chart similar to that of Tangier and Pocomoke Sounds, but the out- 

 lines of the beds, as shown by a few traverses run by the boats and as indicated by the local 

 oystermen, have been sketched in roughly. 



According to such information as it was possible for us to obtain, the beds do not extend above 

 Deep Water Light, with the exception of a few small ones that are seldom fished on the account of 

 the inferiority of the animals. We had not time to determiue ourselves whether the information 

 was correct, but I presume it to be so. 



Below Deep Water Light the beds of any consequence are twelve in number, and of a total 

 area (approximate) of 10.4 square miles. Taking them in order from Deep Water Light to Hamp- 

 ton Eoads they aie the Mulberry Point Bed, Point of Shoals Bed, Jail Island Bed, Blunt Point 

 Bed, White Shoal Bed, Thomas's Point Bed, Kettle Hole Bed, Brown Shoal Bed, Bally Smash Bed, 

 Naseway Shoal Bed, Cruiser's Bed, and the ISfansemond Ridge Bed. The beds are "natural," and 

 the following remarks apply to all. 



Currents. — Nineteen observations were made of the currents, and established that, over the 

 Mulberry Point, Jail Island, and Point of Shoals Beds, the general set of the flood is NW., with a 

 maximum velocity of 0.5 mile per hour, and the general set of the ebb SE., with a maximum 

 velocity of 1.7 miles per hour. These vel©cities were measured after or during moderate to stiff 

 1STW. breezes and spring tides, which conditions would increase the velocity of the ebb current 

 considerably; it is probable that that velocity does not exceed one knot per hour under ordinary 

 circumstances. The set both on flood and ebb is directly across the bed, but the main body of 

 water follows the deep channel to the southward, the ebb striking the shore in Burwell's Bay, and 

 at times washing a good deal of it away. 



Over the Blunt Point, White Shoal, Thomas's Point, Kettle Hole, and Brown's Shoal Beds the cur- 

 rent sets NW. and SE., with a maximum velocity of 0.8 mile per hour on the flood. The ebb on 

 the first quarter showed a velocity of 0.3 mile per hour, and probably the maximum velocity is but 

 little over one knot per hour, as the great body of water passes to the southward of the beds. 



On the southern side of the river, over the Bally Smash, Naseway Shoal, Nansemond Bidge, 

 and Cruiser's Beds, the general set of the currents is NW. and SE., except where the very shoal 

 spots are met, when the current becomes variable in direction though not diminished in force. 

 When the shoal ledge lies in the general direction of the river the effect dots not appear to be so 

 great, but where the shoal extends across the main current it is deflected from its usual course, 

 and forms strong counter currents and eddies. Thus over the Bally Smash Bed the ebb was iound 

 to set to the SE., with a maximum velocity of 1.1 miles; over the Naseway Shoal on one side of 

 the shoal ridge the set of the ebb was SW., with a velocity of 0.4 mile per hour ; while on the other 

 side of the ridge an observation made at about the same time showed a set of 0.2 mile NE. When 

 clear of theobstructing shoals the current sets to the northward and westward on the flood, and to 

 the southward and eastward on the ebb, with an average velocity of 0.5 mile per hour. 



Over the Nansemond Ridge beds and inside of them the flood seis in towards Ragged Creek, 

 and the ebb probably in the opposite direction. 



In order to determine whether the salt water over the beds in the river, and especially over 

 the Mulberry Point, Point of Shoals, and Jail Island Beds was displaced by the fresh water of the 

 spring ebbs, specimens of water were obtained at every two fathoms of depth, on a section across 

 App 11 2 



--v7<« ■ 



