Washington — Igneous Rocks from Eastern Siberia. 179 



doininantly albite-nephelite rock Morozewitch gives the name 

 of " marinpolite." 



IsTcagan Bay. 



All the other Siberian rocks which were sent me by Mr. 

 Maddren come from " the head of Iskagan Bay," a small inlet 

 in lat. 64' 30' N. and long. 172° 40' W., about 230 km south- 

 west of East Cape. The locality is shown on the accompany- 

 ing map, copied from that of Alaska of the IT. S. C. and G. 

 Survey, for the drawing of which I am indebted to Mr. H. H. 

 Robinson. 



77FW 



6S7H 



The character of the locality resembles the other, for Mr. 

 Maddren says of it : " The Iskagan region is a very rugged 

 and mountainous one, the shores of the bay rising up abruptly 

 to snow-covered peaks." The specimens were collected from 

 the talus slopes. 



With one exception these rocks represent lava flows, or at 

 least fine-grained porphyritic forms. It is, of course, impos- 

 sible to say anything of "their age, in the total absence of geo- 

 logical data, but from the partial devitrification of some of 

 them and their general appearance, it is probable that they are 

 not very recent. 



Comendite. — The most interesting of these specimens is 

 dense and compact, with a tendency to platy parting under the 

 hammer, of a general flesh tint, sprinkled with dull greenish 

 specks. 



