PHYSICAL OCEANOGRAPHY OP 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, 23 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 Yachon (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 vicinity 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° near by 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 Lurcher 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 Shelburne 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 
23 Varying from 11.3° to 12.7° during that day (Vachon, 1918). 
