30 THE COPPER RIVER DELTA 



astronomical station, covers the entire delta, and many oljservations 

 were taken on the mountains h'int^ to the east, north, and west. Tills 

 Avork served to locate tlieir position and determine their heights. 



Hydrographic examinations were made at the mouth of the river 

 and at other places. The plane-tahle work covered the shore-line, 

 positions of sloughs, reefs, etc., and the tidal observations were used 

 in reducing the hydrographic work. Meteorological observations were 

 also made, as well as magnetic observations, at Orca and at a point in 

 the middle of the delta. A large part of tiie topogra))h3' was executed 

 by a|)plication of the photo-topographic method. A map on a scale 

 of 1 : SOOUO was prepared from the results of the season's work. 



The longitude depends on the transportation of chronometers, de- 

 termining a sea rate from observations at San Francisco and Seattle 

 and a land rate after iiaving carried the chronometer ashore and made 

 suflicient observations for this pur])ose. 



Tidal observations were carried on at all stations occui)ied by the 

 party, namely, Orca, Kokiniienic, Pete Dalil Slough, and E3^ak River. 

 These observations were made in such a way that the series for con- 

 secutive stations overlap, thus fixing the relation l)etween the tides 

 at the two stations. 



At both Orca and Kokinhenic magnetic observations were made — 

 at tiie former place in May and at the latter in June. 



The photo-topographic camera was continually used. and the neces- 

 sary developing accessories were carried along, so that the negatives 

 were largel}' developed in the field. Owing to the general unfavor- 

 ableness of the weather, no systematic scheme could be carried out, 

 although a large amount of valuable data was obtained. One hun- 

 dred and eighty views were taken with the topographic camera and 

 88 with an ordinary view camera. 



The country in the vicinity of the mouth of the Copper River, as 

 seen when approaching it from th-e sea, has the appearance of a vast 

 snow-peaked mountain range whose tops are covered with perpetual 

 snow. Innumerable glaciers move down the mountain sides and fill 

 the deepl}' cut canyons. From the head of the delta to the ocean reef 

 is a distance of about 25 miles. The delta is 50 miles wide, and the 

 mountains range from 1,000 to 8,000 feet in elevation. The flats at the 

 mouth of the river are cut up into numerous islands b}- the many 

 tidal .sloughs and small streams flowing from the glaciers. Mau}-^ in- 

 teresting features may be noted in regard to this particular localit}^ 

 among which ma}' be mentioned the violent winds, which begin dur- 



