374 



INDEX TO THE STEATIGEAPHY OF NOETH AMEEICA. 



Of the section on McCloud River, in the northeastern belt of the Klamath 

 Mountains, the original description by J. Perrin Smith ^^^ is given below: 



Columnar section of the nnetamorpliic series of Shasta County. 



The McCloud formation is especially well developed in the region of the McCloud Eiver 

 in Shasta County, and from this it receives its name. The formation consists entirely of 

 Carboniferous strata, the Baird siliceous shales, overlain by the heavily bedded McCloud lime- 

 stone, with some beds of igneous rock. The thickness is estimated at about 2,500 feet, but 

 this may be far from the true thickness. 



The Baird shales consist of about 500 feet of black metamorphic siliceous shales, in places 

 calcareous and occasionally sandy. At the top, too, are beds of diabase and other eruptives, 

 which, however, do not seem to make up any considerable thickness of the rocks. The Baird 

 shales extend from near the junction of the Pitt and the McCloud rivers northward for about 

 20 miles along the McCloud, but they were studied by the writer only in the neighborhood of 

 the United States fisheries at Baird. 



The strata have a general dip to the east, but this is very inconstant; their strike is approxi- 

 mately north and south. What underlies them could not be made out. They certainly are 

 younger than the Kennett limestones, but what the interval between the two formations and 

 whether they are conformable or not could not be ascertained. They are probably overlain 



