PALEOZOIC ROOKS, TOTSEN SERIES. 59 



the rock carries much secondary quartz, both in small veins and in lenticular bodies. 

 Some iron pyrite is also present, which on oxidation gives a reddish-brown color to 

 the rock. The quartz veins tend to follow the schistosity and are often locally con- 

 torted and twisted. Some carry irregular veinlets or stringers of epidote. 



The series is believed to be essentially of sedimentary origin, but the sedimenta- 

 tion seems to have been accompanied by basaltic flows, which were later sheared 

 with the sedimentary beds, giving rise to amphibolite-schist, of which the most 

 prominent strip, having an apparent width of several miles, occurs near the southern 

 part of the belt occupied by the series. Here the rock, judging from the bent and 

 crushed remnants of feldspar and augite shown under the microscope, is plainly of 

 igneous origin. Though on account of faulting and folding there is doubtless some 

 duplication of the rocks in the Totsen series, its total thickness, judging from the 

 prevailing dip and distance across the strike, is 6,000 to 7,000 feet. 



Structure. — The Totsen series, like the older rocks composing the range, trends 

 approximately east and west, and though the series as a whole has been intensely 

 folded, the dip in general is monocliual, being, so far as observed, southward, at 

 angles of 60 to 80°; but in the northern part of the belt, John River Valley, for a 

 distance of several miles, seems to follow a north-south syncline in the series. 

 The series is traversed by the major northeast jointing of the range, and by a second- 

 ary structure at nearly right angles to the major jointing. Cleavage was noted at a 

 few localities, but apparently much of this has been obliterated by disturbance. 



Age. — The Totsen series is represented in the geologic section as it appears 

 to occur in the field, namely, above the Skajit series. It thus seems to be younger 

 than the Skajit, but the actual contact between the formations was not seen, as is 

 shown by the gap in the section, and the age relations here indicated can not be 

 demonstrated. Furthermore, while the Totsen series, so far as observed, consists 

 essentially of rocks that seem undoubtedly to belong to the class of older crystalline 

 schists found in Alaska, and can not be correlated with the Fickett series, it should 

 be noted that the observations made were confined to the line of traverse along 

 John River, and the mountains in this part of the field not having been ascended, 

 it is possible that the series may be overlain by or otherwise associated with rocks 

 younger than those described above. The great thickness and probable extent of 

 the Fickett series (to be noted later) to the north of the Skajit formation, makes it 

 not unreasonable to suppose that members of this series may occur on the south side 

 of the Skajit anticlinorium, but this point must be determined by future investigation. 



Correlation. — The Totsen series can be correlated in a tentative way, on lithologic 

 grounds, with the Lake quartz-schist a of Chandlar River. It is less evidently of 



aSehrader, F. C, Reconnaissance along the Chandlar and Koyukuk rivers, Alaska: Twenty-first Ann. Kept. U. S. 

 Geol. Survey, pt. 2, 1900, p. 474. 



