24 
PACIFIC SCIENCE, Vol. XII, January, 1958 
Fig. 2. Stations occupied on previous expeditions. 
Considerable warming and high salinity 
were found in shallow bays such as Bahia 
Guaymas and Bahia Concepcion. Upwelling 
was characteristic along the northern coast of 
Sonora where the temperature was about one 
degree lower and the salinity 0.4°/ O o lower than 
in the neighborhood offshore. Near the mouth 
of Rio Colorado the salinity varied between 
35.2 and 35.7°/oo, probably due to the ad- 
mixture of fresh water. The bottom tempera- 
tures in the northern part everywhere exceeded 
11°C. and the bottom salinity varied between 
35.5 and 36.1%o. 
The next important description of the Gulf 
of California was made by Thorade (1909) in 
a paper on the California Current. He exam- 
ined a great number of ship logs over many 
years and was the first investigator to draw 
monthly surface temperature charts (Fig. 4) 
for the southern part of the Gulf and deduce 
from them the general circulation in the Gulf 
and to correlate the sea surface temperatures 
to the direction of the wind, the orientation 
of the shore line, and the special climatolog- 
ical conditions prevailing in the Gulf. His 
main conclusions were that the temperature 
of the Gulf is independent of the temperature 
in the adjacent ocean and that the low tem- 
peratures along the east coast in winter are 
the result of northerly winds that tend to 
transport surface water away from the coast 
and thus produce upwelling. He also observed 
correctly that during most of the year the 
circulation is counterclockwise in the Gulf 
and that the water enters the Gulf along the 
east coast and leaves it along the west coast. 
He mentioned that "manifold discontinuities 
are observed by a sudden change in tern- 
