NEOZOIC INVERTEBRATES IOI 



there is a considerable mass of coal-bearing strata belong- 

 ing to the Kenai Series of Oligocene sediments, which 

 logically should succeed the Eocene Stepovak Series 

 of Chichagof Cove and vicinity, though their contact has 

 not yet been observed. To the southward, on the north- 

 ern end of Unga Island of the Shumagin group, these same 

 Kenai beds are exposed and contain not only coal but an 

 important series of leaf beds, from which their age has 

 been determined. A tolerably full description of the 

 stratigraphy of the Unga locality has been published by 

 the writer 1 from observations made in 1865, 1872 and on 

 various occasions since. A list of the plant remains, pre- 

 pared by Dr. Knowlton, 2 has also been printed. 



Immediately above the beds of the Kenai Series in the 

 Unga section appear, as the product of apparently con- 

 tinuous sedimentation, a thinner series of beds of Miocene 

 age containing marine invertebrate fossils. This Miocene 

 deposit, much broken up by volcanic dikes and intrusions 

 of lava, extends to the eastward, being found in various 

 localities along the north shore of Popof Island immediately 

 eastward of Unga, where the writer obtained fossils in 1874, 

 and where Mr. Kincaid of the Harriman party also col- 

 lected a number of specimens, to be discussed later. 



The only representative of the Eocene epoch known 

 in Alaska previous to the date of the Harriman Ex- 

 pedition was the Kenai Series, which had been referred 

 by Heer to the Miocene and by others to the Eocene, but 

 which has of recent years been recognized as Oligocene 

 by the present writer and others. 3 



The discovery of unmistakable typical Eocene strata 

 in Alaska, therefore, is of prime importance, as filling a 



Correlation Papers. Neocene. Bull. U. S. Geol. Survey, NO. 84, 1892; pp. 

 240-242. See also : Report on Coal and Lignite of Alaska by William Healey 

 Dall, I7th Ann. Rep. U. S. Geol. Survey, 1895-6, part i, 1896, pp. 807-811. 



*Reporton Coal and Lignite of Alaska (supra), Appendix I, pp. 876-897. 



'Report on Coal and Lignite of Alaska (supra), pp. 838-9. 



