J. S. Diller — Bragdon Formation. 383 



the Sacramento. The essential part of the McCloud-Sims 

 section is given below, beginning with the newer beds on the 

 east. The thickness given is only a rough estimate, making 

 allowances for repetition by many small folds and faults. 



Carboniferous, limestone, (McCloud) - 2000 



" reddish shales and sandstones with much vol- 

 canic material (Baird) .. _ _.. 1000 



" shales, sandstones and tuffs with siliceous 

 conglomerates (of Devonian pebbles) in- 

 creasing in number and size from the top 

 towards the bottom (Bragdon) 2900 



(Unconformity) 



Devonian, dark shale _ 100 



" limestone 150 



" black slaty shales (scarcely any chert) 400 



? • volcanic series - 



Relation of the Bragdon to Volcanic Rocks. — The Red- 

 ding quadrangle contains an extensive series of highly fossilifer- 

 ous sediments from the Devonian to the Tertiary inclusive, and 

 affords one of the most complete records of the volcanic phe- 

 nomena of that interval to be found in the state of California. 

 This is not the place to enter into details concerning this record, 

 and yet it is necessary to consider it very briefly in a general 

 way to elucidate the relations of the Bragdon. Devonian 

 sediments show the existence of andesitic and rhyolitic lavas of 

 earlier date, and during the Bragdon and especially the earlier 

 portion of the Baird there was considerable volcanic activity 

 which continued for a long time and culminated about the 

 close of the Paleozoic. A great sheet of lava and tuffs was 

 formed at that time which appears between the Carboniferous 

 and Triassic sediments. Yolcanic eruptions continued at inter- 

 vals throughout the Triassic and Jurassic but during the Creta- 

 ceous there was a long interval of quiescence, followed by the 

 great eruptions of the Tertiary. It is not to be supposed that 

 volcanic products were in all cases spread equally over the 

 whole Klamath Mountain area for each volcanic horizon. The 

 eruptions were local, yielding large masses at different places 

 at different times, and to establish the horizon of each it is 

 generally necessary to determine their relation to fossiliferous 

 sediments. 



Older than the Miocene, one of the largest among half a dozen 

 horizons of volcanic products in the Redding quadrangle is that 

 on the border of the Paleozoic and Mesozoic. The andesitic 

 and rhyolitic lavas and tuffs of that horizon form a prominent 

 ridge to which Bully Hill belongs, and the whole mass may 

 be conveniently referred to as the " Bully Hill volcanics." Con- 



