352 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



upon the piles of an old uarrow-gauge railroad trestle, across a slough, 

 near Dunibartou Point, and that the men of his party frequently found 

 many upon banks composed of shells of the native species, near where 

 the pipes of the company cross the bay. 



Mr. n. J). Dunn has recently reported, through the press, thQ discov- 

 ery of a full-grown eastern oyster near Mile Eock, in the Golden Gate. 



It is possible that daring the long time eastern oysters have been 

 kept in the bay they have become in a measure acclimated, and that 

 there is a constantly increasing tendency to propagate — that is, the 

 progeny of oysters grown here become hardier with each generation 

 and better adapted to the colder but more equable waters. 



During my hitest examinations of the bay (May and June, 1891) 

 eastern oysters, very large and old, were found in the following places 

 near the sites of former oyster beds: Several adliering to the i)iles of 

 the narrow-gauge railroad trestle across San Leandro Bay; a few upon 

 the rocks at the extreme north iioint of Sheep or Urooks Island, near 

 low-water mark ; a few upon the rocks at Point San Pedro (at entrance 

 to San Pablo Bay). Those from San Leandro Bay doubtless originated 

 as spat from the oyster bed near the entrance to that bay, at the end of the 

 bay northwest from the island. Those from Sheep Island had merely 

 drifted as young across the half mile of distance from the old beds 

 near Ellis Landing, while the San Pedro oysters originated upon the 

 beds between Marin Island and Point San Queutin, a couple of miles 

 distant. 



Mr. H. D. Dunn informed me that wild eastern oysters had been 

 reported to him from some other place near Point San Pedro, but I did 

 not discover them, being without a pilot. These finds are very inter- 

 esting, as showing not only the breeding of the oyster in various parts 

 of the bay, but that the species began breeding several years ago when 

 oysters were laid out in those northern parts of the bay. At Point San 

 Pedro oysters are directly exposed to the influences of the Sacra- 

 mento River. But the largest and most important tract of oyster 

 propagation is in the region of the natural shellbanks of native oys- 

 ters along the east side of the bay, beginning at Bay Farm Island and 

 extending well southward and off into deep water. Ilere wild eastern 

 oysters may be fouiul during the low tides that expose the outer por- 

 tions of the shellbanks. At this place they are numerous, and when 

 the tides are sufficiently low it is possible to gather them by the score, 

 ranging in size from yearlings to those several years old. Thisdci)0sit 

 is at least 4 miles removed from the nearest site of a former t)yster 

 bedding-ground, and there is no doubt about the oysters upon the 

 whole tract being of volunteer growth. A channel several feet wide 

 separates this tract from the old bed on the north, while it is nearly 10 

 miles to the nearest beds on the south. 



Examination of two or three hundred oysters gathered in this region 

 shows the fixing surface for the spat to have been the shells of the 



