Diller — Klamath Mountain Section, California. 351 



information concerning this belt has been greatly extended 

 within the last decade by Fairbanks, Smith and Anderson in 

 the publications already referred to. 



The limestone where fully developed is the largest known 

 in nothern California. It has a thickness of fully 2,000 feet 

 and can be traced almost continuously along the McCloud 

 River for nearly 50 miles. Before reaching the lavas of Mt. 

 Shasta, however, it extends to the eastward, cropping out 

 on the summit of Grizzly Peak, on the divide between the 

 McCloud and Kosk Creek. 



Beneath the McCloud limestone is a thick series of shales 

 and sandstones with some conglomerates and occasional lenses 

 of calcareous material. The sediments are often largely of 

 volcanic matter, and include the " Baird shales '' from which 

 J. P. Smith* has described a large fauna. Above the McCloud 

 limestone is a similar series in the McCloud shales of Smith 

 but not so thick as the Baird formation, and grading upward 

 into an extensive series of volcanic rocks. 



Concerning the collections from the northeastern Carbonifer- 

 ous belt, Dr. Girty reports : 



" A large part of the Carboniferous collections made in 1901 

 and 1902 were derived from horizons stratigraphically referable 

 t.o the Baird shale, the McCloud limestone, and the McCloud 

 shale, and from localities in the typical areas. The faunas of 

 these beds have been listed long since by J. P. Smith, f and the 

 more recent collections add little of material importance to the 

 lists made at that time. It may be remarked, however, that 

 recent collections made in the Carboniferous of Alaska are so 

 suggestive of the fauna of the McCloud shale, by way of con- 

 taining the same or similar species, as to indicate the extension 

 of this fauna, and, possibly, of the earlier Carboniferous faunas 

 of the California province, to this region." 



The Bragdon formation, named by Hershey, J is here referred 

 provisionally to the base of the Carboniferous sediments and 

 require separate consideration. It is a mass of shales with 

 thin-bedded sandstones and lenses of remarkable conglomerate, 

 which is characterized chiefly by the silicious and calcareous 

 pebbles it contains. The pebbles are generally less than an 

 inch in diameter but, very rarely, are 12 inches through, and 

 the majority of them are of cherty quartz. Those of lime- 

 stone are occasionally fossiliferous and on the surface dissolve 

 away, leaving holes in the conglomerate. 



The distribution of the Bragdon formation is peculiar. Its 

 eastern border lies east of the Sacramento, from Morleys to 



* Jour. Geol., ii, pp. 593-602. 



f Jour. Geol., ii, pp. 588-612, 1894. 



{Am. Geol., xxvii, 236. 



Am. Jour. Scl— Fourth Series, Vol. XV, No. 89.— May, 1903. 

 24 



