Dr. G. W. Field, chairman of this department, in his report in 1902 as biologist to the Charles River Dam Commission, makes the following statement about the Charles River oyster:-- The oyster (_Ostrea_), formerly abundant, is no longer living, and, from what indications I have been able to gather, probably became extinct within twenty-five years. Their dead shells are brought up by dredging operations. Their peculiar elongated shape is the result of growth being concentrated at the upper end, as a result of their closely crowded position in the bed, or of an attempt to keep the opening above the accumulating mud, and thus avoid being smothered. The fact that there are few signs of small "seed oysters" tends to prove that the bottom was so muddy that they found few places to "set." From the elongated shape of the shells may be inferred that the amount of sedimentation going on in that particular region was rapid during the life of the group of oysters whose shells are to be found in quantities in the material dredged between Harvard and Brookline bridges. This sediment need not necessarily have been sand or clay, or any material which is persistent, but it might have been flocculent organic débris, which remained but a short time and left little or no evidence, beyond its effect upon the shape of the oyster shells. In the above account Dr. Field not only locates the original oyster beds of Charles River, but also furnishes evidence which indicates the cause of their extinction, _i.e._, the débris and sewage, or waste poisonous, polluting materials, of a large city emptying into the river. This is not only true of the Charles, but also of the Mystic and Taunton river beds, which have been destroyed in like manner. (3) Mr. Ernest Ingersoll, in his report on the "Oyster Industry of the United States," in 1880 mentions that natural oyster beds were once at Weymouth, Ipswich, Barnstable and Rowley. Nothing further can be learned concerning these places. (4) _Wellfleet._--An extensive oyster bed was found at Wellfleet Bay, which not only furnished a sufficient supply for the first settlers, but enabled the inhabitants of Wellfleet to carry on a considerable trade by shipping them to Boston and other ports, until it was finally destroyed in 1775. Its destruction was due to overfishing and the utilization of the shells for lime, which soon destroyed the natural bar. (5) _Chatham._--A natural oyster bed once existed in the Oyster Pond, but no trace of it now remains. (6) _Harwich._--Herring River in the town of Harwich still possesses the remnants of a natural oyster bed, as occasionally a few oysters can be gathered along its banks. This bed once comprised a stretch of three-quarters of a mile along the river. (7) _Yarmouth._--The town of Yarmouth once possessed a natural oyster bed in Mill Creek, but this was fished out by 1895 and then granted for oyster culture.