INTRODUCTION 



The work of the 'Albatross' in the Lower California region, as set 

 forth in the fifteen reports comprising this volume, added much to 

 what was already known of a section of coast and sea bottom occupying 

 an intermediate position between the previously explored North Pacific 

 and Panamic regions. During many years of hydrographic and fisheries 

 work by this vessel, between California and Alaska, and also between 

 Panama, the Galapagos Islands and southern Mexico, oceanographic 

 knowledge respecting the eastern Pacific had been greatly advanced. 



The narrow, elevated and arid peninsula of Lower California, nearly 

 800 miles long, that forms the western boundary of the great Gulf of 

 California, has many forms of animal and plant life that are peculiarly 

 its own, especially in its southern part, which touches the -Tropic of Cancer. 

 The littoral marine fauna" is no less interesting, the region being a 

 meeting ground of many northern and subtropical forms. The pearl 

 oyster is found far up toward the head of the Gulf, while corals of several 

 species extend well into it. Clipperton, the only true atoll in the eastern 

 Pacific, lies 600 miles below the mouth of the Gulf. The Pacific green 

 turtle abounds on both- sides of the Peninsula and the tortoise-shell 

 about its southern end. Two species of marine mammals Of Antarctic 

 origin, the, elephant seal and the Guadalupe fur seal, were formerly 

 abundant along the entire west coast of the Peninsula, while the Cali- 

 fornia sea-lion finds the southern limit of its range at the mouth of the 

 Gulf. There are no other pinnipeds in this region. 



The surface waters of the Gulf are decidedly warmer than in corre- 

 sponding latitudes just outside of it and here sea birds of subtropical 

 distribution abound. Boobies are found throughout the Gulf and the 

 frigate bird and the tropic bird about its mouth. Certain auklets reach 

 here their southern limits of 'distribution. 



Ocean depths of 2000 fathoms are found within the mouth of the 

 Gulf, the thousand fathom curve extends nearly a third of its length 

 inland, and the hundred fathom line to its northern end. Bottom 

 temperatures in the Gulf ranged from 49° Fahrenheit down to 44° in 

 depths of 200 to 360 fathoms, and 37° in depths of 800 to 1000 fathoms. 

 Bottom temperatures of 36° were found in the mouth of the Gulf at 

 depths of 1200 to 1500 fathoms. Off Cape San Lucas in 630 fathoms, 

 the bottom temperature was 39°, while at the surface it was 73°, a differ- 

 ence of 34°. 



Currents along the west side of the Peninsula are in general southerly, 

 those below the mouth of the Gulf northerly. 



