40 Smithsonian Exploration in Alaska in 1904 



Cape Halkett, one of the most prominent promontories along this 

 part of the coast (pi. x, D), terminates in an ice cliff rising thirty 

 feet above tide level, and is overlain by a foot or two of muck, 

 which in turn is carpeted by a nap of moss and grass at the surface. 

 Judging from the topography, the ice at this locality may extend 

 inland several miles. Its thickness is not known, since its lower 

 limit lies below tide level. As shown in the view, the cape is being 

 rapidly cut back by wave action, which undermines the cliff at tide 

 level until by its own weight the ice breaks off in large blocks and 

 is ground up by the surf. 



" Of the Kowak clay containing Pleistocene vertebrate remains, 

 referred to by Doctor Dall in connection with the ground ice, but 

 little was seen by the writer. Observation, however, has been suf- 

 ficient to suggest that, if present along the coast between the Col- 

 ville and Chipp (Ikpikpuk) River, they are not only far from con- 

 tinuous, but are probably of very limited occurrence. Along the 

 northwest part of the coast, the only locality at which what seems 

 with certainty to be the Kowak clay was observed, is at Woody 

 Inlet, about fifty miles southwest of Point Barrow. As this inlet is 

 not far from the seventy-first degree of north latitude it is thought 

 that the deposit may be near that in which Captain Beechey's party 

 obtained elephant remains." 



4. PRESENT DRAINAGE FLOOD-PLAIN ICE 



All the rivers of Alaska present along their valleys two distinct 

 classes of unconsolidated deposits. One consists of the low banks, 

 which are only ten to twenty feet above the river and which are 

 composed of fine dark alluvium alternating with layers of vegetable 

 matter. Here buried logs and the upright stumps and trunks of 

 trees are frequent, while their surfaces have often a covering of 

 fresh mud, deposited by the spring floods. Lenticular masses of ice 

 are frequently exposed in the banks of these flood-plain alluviums. 

 The other class are the older deposits of higher and lighter colored 

 silts without vegetable matter, which are cut by the rivers more 

 rarely. These vary from fifty to two hundred feet in height. 



The newer flood-plain ice occurs unconformably with alluvium 

 and humus. Russell '* amplifies on the formation of " Stratified 

 Ice in the Tundra " as follows : 



" The great number of lakelets on the surface of the tundra ren- 



** Notes on the Surface Geology of Alaska. Bull. Geol. Soc. Am., Vol. L 

 1890, p. 128. 



