PHYSICAL OCEANOGRAPHY OF THE GULF OF MAINE 593 



water close in to the western coast of Nova Scotia warms to 10° to 12° by August 

 from St. Marys Bay to Yarmouth. Yarmouth Harbor he found only slightly warmer 

 (12° to 12.5°) than the open waters at its mouth, and it had about this same tem- 

 perature on September 8, 1916,^' but the surface of St. Marys Bay rises to a consid- 

 erably higher temperature. The maximum for this bay can not be stated, data for 

 the inner part of the bay for August being lacking. Craigie and Chase (1918), how- 

 ever, found its surface progressively warmer, passing inward, from 9° to 10° at the 

 mouth to about 11° abreast of Petite Passage, 13° to 13.5° off Weymouth, and to 

 14.8° at the head during the second week of July in 1915; and as Vachon (1918) 

 again had readings of 11.08° abreast of Petite Passage and 12.92° off Weymouth on 

 September 4 to 5, 1916, it is not likely that August sees the surface temperature rise 

 much above 15° anywhere in St. Marys Bay. 



A coastal belt skirting Cape Sable, 12 to 15 miles wide, like the vicioity of 

 Lurcher Shoal, is characterized by surface temperatures lower than 10° throughout 

 July. This, no doubt, results from thorough stirring by the tides, which proverbi- 

 ally run strong around the cape, causing a mixture in varying amount with the icy 

 water that persists until midsummer in the deeper strata next the coast, a few miles 

 to the eastward (p. 681). 



Near the cape Dawson (1922, p. 85, station Q) had surface readings of 5.3° to 7.5° 

 (usually from 0.5° to 1° higher at high water than at low water) during the first half of 

 July, 1907. By the last week of that month he found that the mean surface temper- 

 ature 12 miles out from the cape had risen to about 9° at high tide and to about 8.4° 

 at low, with a slightly greater difference between high and low tide temperatures (aver- 

 age about 9° and 7.2°) closer in to the land, and with a maximum of 11.95° at the high- 

 water slack and a minimum of only 5° at low-water slack on the 20th. Our own 

 more recent record of 10.28° nearby on July 25, 1914 (station 10230), falls well within 

 these extremes. 



These temperatures suggest that the flood current, flowing westward past the cape, 

 draws warmer surface water toward the land from offshore, but that the ebb, flowing 

 to the eastward, carries out water that has been thoroughly mixed by the currents 

 swirling around the cape. 



Surface readings of 10° to 12° on several lines along the coast sector between 

 Yarmouth, Nova Scotia, and the cape, for the middle of July (Dawson, 1922), show 

 that this narrow cold pool off Cape Sable becomes entirely isolated from the low 

 temperatures about Lm-cher Shoal before the last of that month by the development 

 of a warmer surface over the intervening area, but is continuous with still lower tem- 

 peratures to the eastward along the outer coast of Nova Scotia until August, witness 

 a surface reading of 6.62° at low water a few miles off Shelbiu-ne on July 27 in 1914 

 (station 10231), no doubt reflecting some updraft of the icy water from below with 

 the outflowing tide. In 1915, however, the Canadian Fisheries Expedition found no 

 surface water colder than 9.7° off this part of the coast on July 21 (Bjerkan, 1919). 

 On September 6 of that year (station 10313) the surface was 15° 10 miles off Cape 

 Roseway, 13.3° 10 miles south of Cape Sable on September 2 (station 10312), and 

 13.6° near by on August 11, 1914 (station 10243). Apparently, then, if the cold sur- 

 face persists as late as August off the Cape, it becomes reduced to an isolated pool 



n Varying from 11.3° to 12.7° during that day (Vachon, 1918). 



