ALASKA. 67 



the group, six miles south of Saint Paul's) would seem to 

 indicate quite recent action, and this is the only place on the 

 Prybilov Islands where anything has been discharged from a 

 crater at so late a date. 



Since the period of the upheaval of the group under discus- 

 sion the sea has done much to modify and enlarge the most 

 important island, Saint Paul's, while the others, Saint George 

 and Otter, being lifted abruptly above the power of water and 

 ice to carry and deposit sand, soil, and bowlders, are but little 

 changed. 



Saint Paul's Island is the largest and far the most import- 

 ant and valuableof the whole group. Upon my first arrival there 

 in April, 1872, I was surprised to find that no steps had been 

 taken to obtain an accurate or eveu approximately correct idea 

 of the size and shape of it. I at once set to work ui)on it, and 

 give herewith as the result of this labor the first definite figures 

 as to its dimension and area, together with a map showing the 

 outline and topography, with special sketches of the area and 

 position of each fur-seal "rookery" or breeding-ground. 



The Eeef Point of the island stands in latitude 57° 8' north, 

 and west longitude 170° 12', being the most southerly land. 

 The island is in its greatest length, between northeast and 

 southwest points, 13 miles air-line, and in greatest width a 

 little less than six. It has a superficial area of about 33 

 square miles, or 21,120 acres, of diversified, rough, and rocky 

 uplands, small, rounded hills, which either set down boldly to the 

 sea, or fade into wet, mossy flats and dry drifting sand-dune 

 tracts. It has 42 miles of shore-line, 16J of which are used 

 by the fur-seals en masse. 



At the time of its first upheaval above the sea it must 

 have presented the appearance of ten or twelve little rocky- 

 bluff islets or points, upon some of which were craters, vomit- 

 ing breccia and cinders, but with little or no lava overflowing ; 

 the plutonic power after this ceased to act, and the sea com- 

 menced the work of building on to the skeleton thus created, 

 and to-day so thorough and successful has it been in its labor 

 of sand-shifting, together with the aid of ice-floes, in their ac- 

 tion of grinding, lifting, and shoving, that nearly all of the 

 scattered islets, within the present area of the island, are com- 

 pletely bound together by bars of sand and bowlders, which are 

 raised above the highest tides by winds that whirl the sand up 



