Gulf of California — Roden 25 
Fig. 3. Distribution of winds, temperature, and salinity in March, 1889. 
perature” in the vicinity of Cabo San Lucas, 
which might well have been the first descrip- 
tion of the San Lucas front. 
Schott (1935: 208) described the Gulf of 
California as part of the Mexican region, a 
region defined roughly as lying between the 
Gulf of Tehuantepec and Cabo San Lucas and 
extending seaward between the California 
Current and the North Equatorial Current. 
The Mexican region is characterized by a very 
high surface temperature and very weak cir- 
culation. He briefly mentioned the tempera- 
ture discontinuity near Cabo San Lucas and 
drew attention to the frequent hurricanes in 
that region. 
In the spring of 1939 the Scripps Institution 
of Oceanography sent an expedition into the 
Gulf led by H. U. Sverdrup on the "E.W. 
Scripps.” Fifty-three stations were made in the 
Gulf (Fig. 2) taking temperature, salinity, 
oxygen, calcium carbonate and plankton ob- 
servations on each station from the surface to 
the bottom (Sverdrup and staff, 1943). These 
data are still the most complete ever taken 
in the Gulf. Sverdrup’s main conclusions were 
that the Gulf can be subdivided into two 
parts, a northern part and a southern part, 
separated from each other by a submarine 
ridge which comes to within 200 m. below 
the surface. The water mass to the north is 
largely of local origin and formed by con- 
vective currents in winter, the water to the 
south is nearly the same as in the adjacent 
ocean and only modified slightly at the sur- 
face by extensive evaporation (Sverdrup, 
1941). 
In late fall of 1940 the "E. W. Scripps” 
made a second trip to the Gulf. The chief 
