BIGELOW: EXPLORATIONS IX THE GULF OF MAINE. 73 



The profile from Boston Light-ship to German Bank (fig. 29) shows 

 conditions in Massachusetts Bay, over both arms of the deep basin, 

 on Jeffrey's Bank, and over the coast slope of Nova Scotia. From 

 Station 6 to 7 salinities were very uniform at all depths, except for a 

 slight upwclling of salt water above twenty fathoms at the westerly 

 end, thus paralleling the temperature profile (fig. 16) and for the fact 

 that there was no appreciable increase in salinity below forty fathoms 

 in the isolated basin at Station 2, i. e. below the depth to which the 

 enclosing sill rises. Passing easterly from Station 7, the entire mass 

 of water above seventy fathoms becomes salter, all the curves ap- 

 proaching the surface, that for 32.5 rising from thirty fathoms to the 

 surface, while the curve for 33 lies at about twenty-five fathoms at 

 Station 24, instead of at fifty fathoms as at Station 7. Below seventy 

 fathoms, however, there is very little difference between the two sta- 

 tions. Our profile thus shows that the wedge of comparatively fresh 

 water off ^Massachusetts Bay was not traceable below about seventy 

 fathoms. 



Over Jeffrey's Bank the water was appreciably fresher at all depths 

 than it was either west or east of it, the curve for 33 showing a pro- 

 nounced downward swing from twenty-five fathoms at Stations 23 

 and 24 to fifty fathoms at Station 25. But its upper twenty fathoms, 

 though fresher than at Station 24, had a higher salinity than in the 

 region west of Station 7. The whole of the eastern basin was Salter 

 at all depths than the regions west of it, the curve of 33.6 rising to 

 within about forty fathoms of the surface at Station 28, whereas in 

 the western basin, water of this salinity was only found below ninety- 

 five fathoms. At all depths down to about twenty-five fathoms salin- 

 ities were highest at Station 31; but below that depth at Station 28; 

 for example, the curve of 33.8 lies at sixty-five fathoms at Station 31, at 

 fifty fathoms at Station 28; and the curve for 34 must show an even 

 more pronounced rise, for water of that salinity or over was found 

 at Station 28, from eighty fathoms down to 120 fathoms, whereas at 

 Stations 27 and 31 the bottom water was only 33.9 and 33.8 respec- 

 tively in 100 and in seventy-five fathoms. 



Over German Bank, as already pointed out, the water was between 

 32.7 and 32.9 from surface to bottom. 



The west to east extent of the fresh Penobscot water is shown by a 

 profile running from Piatt's Bank across JeftVey's Bank to the neighbor- 

 hood of Mt. Desert Rock (fig. 30) and the breadth of the coast-band 

 of comparatively fresh water off the mouth of Casco Bay is illustrated 

 by a profile from Station 15 to Station 24 (fig. 31). A similar profile 



