the other hand, on either side of the mo-aths of these estuaries the 

 frequency of returns is high. Note also the high ijercentage returns 

 from bottles dropped from Georgia southviard. 



As to bottom water, there are three items which might be 

 mentioned: 



a. There is an area extending from south of Nantucket 

 Shoals westward to the offing of New lork from about 30 fathoms 

 to 50 fathoms which appears to be somewhat isolated from the 

 general circulation pattern. Following the vernal development 

 of the pycnocline this lens of water retains its winter charac- 

 teristics, remains in the same geographic location and does not 

 become modified until the autumn overturn. There appears to be 

 restricted interchange of some of the water seaward with slope 

 water. In other words the portion of the continental shelf be- 

 low the pycnocline tends to stagnate for about 6 months of the 

 year. 



b. Our observation posts on lightships reveal a raid-summer 

 inshore movement of bottom water along the coast from Virginia 

 to New Jersey and subsequent upwelling, presumably due to off- 

 shore movement of surface waters due to -wind shear. How far in- 

 shore of the lightships this intrusion occurs we do not know. 



They also suggest a downx-jelling during the coldest parts of 

 the winter when waters next to the coast chill to low temperatures 

 and subsequent offshore movement when resulting densities reach 

 below those of the adjacent offshore vjaters. This mechanism ap- 

 pears to occur in areas farthest from river mouths where the 



