UPPER CEETACEOUS. 701 



fossil mollusks and plants have been obtained from this area, frona which it would appear to 

 include beds referable to the Middle or Lower Cretaceous « and to the Laramie period, and it 

 is not improbable that the series is a consecutive one between these hmits, as the total thickness 

 represented must be very great. * * * The rocks comprise, in £heir lower portion, coarse 

 conglomerates, graywacke sandstones, yellowish and gray quartzose sandstones, and dark cal- 

 careous slates. The upper portion, in which Laramie plants are found, consists chiefly of rather 

 soft sandstones, shales, and clays, generally of pale colors. Evidence of contemporaneous 

 volcanic action is observable in both parts of the series, and the higher beds include Ugnite coal 

 of good quality. 



Some miles farther up the Lewes, midway between the Little and Big Salmon rivers, pecu- 

 har green graywacke sandstones and green, highly calcareous conglomerates occur, which are 

 provisionally referred, though with some doubt, to the Cretaceous. They are at least newer 

 than the Paleozoic rocks, being composed of fragments of those and of granites.'' 



Conglomerates and sandstones similar to the last are again found near the lower end of 

 Lake Labarge, on the east side, and are associated with black calcareous slates, wliich recur in 

 several places along the same side of the lake, farther up, and from which a few fossils have been 

 obtained. These seem to show that the beds are on or near the horizon of series C, of the Queen 

 Charlotte Islands, which is of Middle Cretaceous age, approximately equivalent to the Gault." 



On the Upper Pelly River, 43 miles below Hoole Canyon, a single low outcrop of hard dark 

 shales, containing fossil plants of Cretaceous or Laramie age, was found, but in the absence of 

 ftirther exposures along the river in that vicinity nothing can be said of the extent of tins area, 

 except that it must be quite limited in width. Again, on the Stikine River, between Glenora 

 and Telegraph Creek, there are local occurrences of conglomerates and soft sandstones which 

 may be regarded as probably Cretaceous, though no paleontological evidence is forthcoming. * 



The position of these last-noted areas, as well as that of those along the Lewes River, 

 occurring as they do in a zone of country immediately within the line of the Coast Ranges, is 

 analogous to that held by Cretaceous rocks on the Skeena and in other locahties still further 

 southward in British Columbia. Further investigation will probably show that the rocks of 

 this age occur in many additional places, and occupy somewhat extensive areas in tliis belt of 

 country. In the vicinity of the Lewes, particularly, it is noted that the plane of the original 

 base of the Cretaceous, now thrown into a number of folds, is about that of the present surface 

 of the country, and these rocks may therefore be expected to recur frequently in the form of 

 troughs or basins, more or less strictly limited and only to be discovered in detail by thorough 

 examination. The loose material brought down by the Big Salmon River appears to indicate the 

 existence of a considerable development of these rocks not far up the valley of that stream. 



P-Q 4. LOWER YTIKON, ALASKA. 



The large area mapped as Cretaceous on the lower Yukon includes the Nulato 

 sandstone, and the strata probably range in age from Lower Cretaceous to upper 

 Eocene, according to Brooks,"^'' who says: 



Cretaceous rocks outcrop almost without break on the lower Yukon from the mouth of the 

 Melozi River to the head of the delta and northward into the basin of the Koyukuk River. In 

 this part of the Yukon Valley Dall made the first geologic observations in the interior of Alaska 

 over 40 years ago. In his summary of Alaskan geology,'' made many years after, he assigned 

 some coal-bearing beds to the Kenai (Eocene) and reported that they were succeeded by 

 marine fossil-bearing sandstone. Spurr ^ corroborated Call's observations and, accepting 

 Eocene as the age of the underlying coal-bearing beds, assigned the succeeding strata to the 



» In the opinion of T. W. Stanton these strata are probably of Jurassic age. — B. W. 



' In the opinion of A. H. Brooks these strata are probably of Kenai (Eocene) age. — B. W. 



c Dall, W. H., and Harris. G. D., Correlation papers— Neocene: Bull. U. S. Geol. Survey No. 84, 1892, pp. 347-348. 



<« Eighteenth Ann. Kept. U. S. Geol. Survey, pt. 3, 1898, p. 196. 



