BIGELOW: KXPLORATIONS IN THK GULF OF MAINE. 55 



sections, show that the rehitive distribution of temperatures at this 

 depth was in a general way the opposite of what it was on the surface, 

 the lowest temperatures being encountered in the west, in Massachu- 

 setts Bay, off Cape Ann, and in the trough west of Jeffrey's Ledge, the 

 highest in the east, off the coast of Nova Scotia (Stations 29 and 31 ), and 

 in the Grand Manan Channel. The extreme range, at this depth, was 

 from about 42° to about 51°, the former characterizing the cold area 

 delimited above, the latter encountered only at Station 31. In general 

 the twentj'-five fathom temperature in the northeastern part of the 

 Gulf was between 48° and 49°. The curve for 48° runs southerly from 

 the mouth of Penobscot Bay far enough to include Jeffrey's Bank, then 

 turns northward again toward the coast, which it parallels at a dis- 

 tance of about twenty miles, until the meridian of 67° 25' is reached, 

 when it once more bends to the southward. Off the mouth of Casco 

 Bay there was an isolated area where the twenty -five fathom temper- 

 ature was 48° or higher. And off Cape Cod, Station 43, the temper- 

 ature at twenty-five fathoms was likewise above 48°. The chart for 

 this level is constructed only for July and early August, and our ob- 

 servations show that at least in the western part of the Gulf there is 

 a decided rise in temperature at twenty-five fathoms fi'om July 9 to 

 August 31, the water shown on the chart as 42° warming to 45°^6°. 

 Bottom temperatures. — The curves for the temperatures at the bot- 

 tom (Plate 1) show that, like those for twenty -five fathoms, there was 

 a regular rise, both at corresponding depths and al)solutely, passing 

 northeastward from Cape Ann to Nova Scotia. Thus at Stations 2, 

 3, 5, 6, 7, 12b, and 24, the bottom temperatures in depths of from 40 

 to 120 fathoms were constantly below 42°, the minimum being 39.2 at 

 Station 12b in the trench between Jeffrey's Ledge and the mainland. 

 That is to say, in July, the bottom temperature over the western arm 

 of the 100 fathom basin, in the deeper parts of Massachusetts Bay, 

 below say forty-five fathoms in the trench west of Jeffrey's Ledge, 

 and over Piatt's Bank was extremely uniform, usually 40.3°. But as 

 we ran eastward we found higher and higher bottom temperatures, 

 irrespective of depth. Thus, at Station 27, on the western edge of the 

 eastern arm of the 100 fathom basin, in 100 fathoms, the bottom read- 

 ing was 43°; at Station 28, thirty-five miles further northeast, in 120 

 fathoms, it was 45.5°; at Station 29, on German Bank, in thirty-five 

 fathoms, between 48° and 49°, i. e., only about 1.5° below the surface 

 reading; and some 7° or 8° warmer than the bottom temperature at a 

 corresponding depth in Massachusetts Bay, 6° warmer than at thirty- 

 five fathoms over Piatt's Bank. Successive stations passing north- 



