JURASSIC. 



575 



Martin ^'^^ describes the district north of Alaska Peninsula and states the 

 sequence of rocks as follows: 



The region described in tkis report covers an area of about 4,900 square miles, situated in 

 southwestern Alaska, west of the southern half of Cook Inlet and north of the Alaska Peninsula. 

 It comprises the greater part of the drainage basin of Kvichak River, which is the outlet of 

 Iliamna and Clark lakes, and of the streams flowing into Cook Inlet from the west, south of 

 and including Tuxedni Bay. It lies between the parallels of 59° and 60° .30' north latitude and 

 the meridians of 152° 30' and 157° west longitude. 



Most of the northeastern part of this region lies within the Chigmit Mountains and consists 

 of high, rugged mountain masses with narrow intervening valleys. The general elevation of 

 these mountains is from 4,000 to 6,000 feet, although many peaks near the north end of 

 Clark Lake are 7,000 feet high, and the highest peak of the whole district is Mount Iliamna, 

 between 9,000 and 10,000 feet. 



At Iliamna Bay the mountains extend eastward to the waters of Cook Inlet. Both north 

 and south of this point albeit of foothills and lowlands from 2 to 10 miles in width reaches from 

 the edge of the high mountains to the shore of the inlet. Much of the coast is deeply embayed, 

 Tuxedni Bay, Iniskin Bay, and Iliamna Bay extending into the high mountains, while the other 

 bays have their heads in the foothill belt. * * * 



The following table shows what is now believed to be the probable geologic sequence: 



General section of rocks in the Iliamna and Clark lakes region. 



