236 University of California Publications in Geology [Vol. 11 



PAGE 



Occurrence of thick beds of shale 267 



Analyses of Franciscan cherts and shales 268 



Metamorphism of the cherts by Franciscan intrusives 270 



Changes in color and structure 270 



Development of quartzites 271 



Quartz veins 271 



Spherulitic cherts _ 272 



Fusion and assimilation of cherts 272 



Condition of cherts at time of intrusion 273 



Mammillated chert 273 



Alteration of chert to glaucophane schist 275 



The occurrence of bedded cherts in the Monterey group 278 



Lithologic types in the Monterey group 278 



Diatomaceous earths 279 



Diatomaceous shales 279 



"White shales" 281 



Monterey cherts , 282 



Bedded cherts 282 



Flinty cherts 288 



Analyses of cherts and shales 290 



Other formations of the Monterey group 291 



Limestones 291 



Sandstones 291 



Tuffs 291 



Other formations in California similar to the Monterey group 292 



Origin of the Monterey cherts 292 



Hypothesis of secondary silicification 292 



Facts opposing the hypothesis that cherts are silicified diatomaceous shales 295 



Alteration of chert 299 



Comparison of the bedded cherts of the Monterey and Franciscan groups 303 



Occurrences of radiolarian rocks 304 



The radiolarian earths of Barbados : 305 



Radiolarian mudstones 308 



In Gondwana series _ 308 



Badiolarian rocks of Australia 309 



Diatomaceous earths containing radiolaria 312 



The radiolarian cherts 313 



Klamath Mountains 313 



Sierra Nevada 313 



Washington 314 



Alaska _ . « 314 



Codden Hill beds 316 



Gower 318 



Mullion Island 319 



Southern Scotland 320 



Ireland _ _ _ 324 



