216 V. D. WALCOTT — PKK-CAMBRIAN FOSSILIFEROUS FORMATIONS 



Feet 



2. Cliocolate-browii, dull, and yellowish green sandy and argillaneous 



shales, with sandstone in narrow bands and 21 feet of limestone 



in thin layers near the middle and base of the stratum 625 



3. The sandstone and sandy shales become less prominent, the argil- 



laceous and calcareous strata replacing them, 62 feet of limestone 

 occurring in 522 feet of strata 522 



4. Black argillaceous shale, with cliocolate and greenish sandy and 



argillaceous shales beneath 100 



5. Three feet of compact, mottled, buff limestone interbedded in 15 



feet of brown sandy shale .... 18 



6. Black, chocolate, and various cotored sandy and argillaceous shales. 830 



7. Massive band of irregular, thinly bediled limestone, gray and l)uff, 



except near the chocolate-colored upper stratum, with thinly 

 bedded limestones below ; conchoidal fracture 50 



8. Dark argillaceous shale, with a strongly marked band of a deep 



maroon color and drab, yellowish green, and dark or brownish 

 black 450 to 650 



Total thickness of lower division 3,420 



Total thickness : 



Upper division 1,700 



Lower division 3,420 



5,120 



Limestone in upper division ... 138 



Limestone in lower division , 147 



285 



Unkar ierrane. — This section is arranged from the summit of the forma- 

 tions downward. 



Feet Feet 



1. a. Massive beds of gray to reddish magnesian limestone, passing • 



below into a calciferous sandrock 50 to 150 



h. Light gray shaly sandstone and irregular massive beds of 



vellowish brown sandstone 325 



475 



2. Lava beds : 



a. Dark green basaltic rock, with a reddish tinge 100 



h. Layers of a reddish brown sandstone 8 to 10 



c. Solid, compact lava, of a dark green and reddish tinge 70 



d. A layer of sandstone, 1 foot in thickness, caps a massive flow 



of dark green lava 100 



e. A flow^ not unlike " d," and capped by a layer of sandstone 



2 feet in thickness 70 



/. A layer of vesicular lava, with a thin stratum of sandstone 



at the summit 10 



(). Solid, compact lava, of a dark green and reddish tinge 175 



}i. Reddish brown sandstone, compact and slighth' metamor- 

 phosed toward the summit 15 



