19033 A Great Shark Trap 



Lynn Canal, Chilcat and Chilcoot rivers, thence 

 westward to Sitka. 



But I shall not tire the reader with details of can- 

 nery operation nor of the various rivers we examined. 

 There were, however, some other matters which en- 

 gaged our attention on the way. 



The north end of Wrangel Island is indented by a 

 peculiar little flask-shaped bay flooded deep at high 



r . , . . r r i 1 r and the 



tide but otherwise a mass of soft white mud, for it s i ff p er 

 receives the glacial detritus (very fine clay) brought sharks 

 down by the large and swift Stikin River. Not far 

 away stands a cannery from which tons of salmon 

 heads and entrails are thrown into the sea. This 

 offal attracts large numbers of the great sleeper shark 



Somniosus microcephalus a twenty-foot long, 

 sluggish, greedy fish which gorges itself to repletion 

 and then retreats at high water to rest in the adja- 

 cent bay. Ebb tide leaves it helpless in the mud; and 

 during the course of a summer great numbers of 

 sleepers and other sharks are thus destroyed. In the 

 end, of course, the flesh decays, but teeth and occa- 

 sional fin spines are preserved as fossils, so that when 



centuries hence the bay fills up and dries out, 

 it should form a very interesting ground for collectors. 



In Kern County, California, a similar fine clay Ken 

 sediment scattered along the plains at the foot of the 

 once glaciated Sierra carries enormous numbers of 

 sharks' teeth, especially of an extinct mackerel-shark 

 - Isurus planus which must have been fifty feet 

 long. With these appear occasionally the teeth of a 

 still greater white shark Carcharodon branneri 

 much more than a hundred feet long a veritable 

 "man eater," although in those days there were no 

 men for it to eat. Multitudes of teeth of smaller 



C 137 1 



