378 TRANSACTIONS OF THE [dEC. 18, 



[ Zoology of Puget Sound. Columbia University Contributions No. 6.] 



OBSERVATIONS ON THE PLANKTON OF PUGET 

 SOUND. 



By J. I. Peck and N. R. Harrington. 



(Plates XXXVII. and XXXVIII.) 



In consequence of former studies in planktonic work in the 

 shallow waters of Buzzard's Bay, on the southern coast of Mas- 

 sachusetts,* the authors of this paper have sought opportunity 

 of studying some of the facts of the vertical distribution of sim- 

 ilar forms over greater depths. Such an opportunity came dur- 

 ing the summer of 1896, through the Columbia University Zo- 

 ological Expedition of that 3'earf to Puget Sound (Pacific Coast), 

 where our collections were made by the junior author with a 

 simple apparatus, designed in advance by both, but constructed 

 and operated by him. 



The most recent interpretation^ of the very irregular coast 

 line of Puget Sound district is that the Cretaceous areas of Ore- 

 gon have been here turned on edge, while numerous depressions 

 and emergencies of Eocene times, augmented by glacial action,^ 

 have resulted in the very deep bays with their many islands, and 

 the deep inland fresh-water lakes of the State of Washington. 

 Other authorities attribute more of these conditions to the action 

 of glaciers alone. In many instances precipitous cliffs dip per- 

 pendicularly into the sound for a depth of from 600 to 900 feet,^ 

 and in water of 30 fathoms average depth there maybe a sudden 

 drop over a very limited area to 150 or 200 fathoms. 



Over one such depression of the bottom, at Lat. 48° 5' N., 

 Long. 122° 38' W. samples of water were taken for quantitative 

 estimate of the plankton through a vertical of 112 fathoms. 

 There is represented in the diagram, Plate I., from the Coast 

 Survey Map No. 6400 of the United States Government, the ir- 

 regular coast line of this body of water, and in the narrow chan- 

 nel at its entrance is denoted the point — indicated by a star in a 

 circle — where the collections here to be considered were made. 

 There is also given in the lower left-hand corner of tiie plate a 

 detail map of the area around the above point, enlarged and 

 showing the soundings of the immediate district. The date 

 was September 1, 1896, at 2 o'clock in the afternoon, at low 



* Sources of Marine Food, U. S. Fish Com. Bulletin, 1895, p. 356. 

 t Described in Trans. N. Y. Acad. S(i., Vol. XVI., pp. 33-42. 

 i See American Geologist for Marcti and April, 1897. 



