122 ALASKA GEOLOGY 



represented on the Alaskan coast and many of the species 

 might be dredged to-day in the channel near Douglas 

 Island, still there are three or four which are not now 

 found, except considerably further north; and the condi- 

 tions under which this fauna existed were doubtless meas- 

 urably colder than at present in the same locality. 



