... Cretaceous Deposits of the Pacific Coast

Front matter

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Preface

This paper is the result of a study begun in 1894 upon an interesting collection of Upper Cretaceous fossils from a new locality in Southern Oregon, locally known as the ** Forty-Nine Mine," but referred to here as the Phoenix Beds.

The special feature of interest in this collection is the large percentage of individuals and species of the genera Schloenbachta^ Scaphites^ and the aberrant forms of cephalopods, types for the most part that were unfamiliar upon this Coast. The contents of this collection was referred to in the May-June number of the Journal of Geology, 1895.

Since the first visit to this locality almost every year has added new and important species from the same place, and from a quite similar locality on the opposite and southern slope of the Siskiyou Range, near the village of Henley, Siskiyou County, California. These two localities evidently belong to the same coastal basin of the Cretaceous, and are here included in what is called the Oregon Basin.

From this fauna the study was naturally led to the Chico deposits of the Sacramento Valley, and from these to the Horsetown and the whole of the Cretaceous.

In offering this paper for publication the author wishes to acknowledge the kindly interest and assistance of his instructors and co-workers, Drs. J. P. Smith, T. W. Stanton, J. C. Merriam, and others, who have shown not only professional courtesies, but have aided the work by a friendly appreciation and a cooperative spirit.

The conclusions that have been reached by this study, while they may not be final, are nevertheless believed to be important in the development of our knowledge of West Coast geology, and in the study of the Great Past and its biological and physical geography. F. M. A.

December 17, 1900.

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CRETACEOUS DEPOSITS OF THE PACIFIC

COAST.

BY FRANK M. ANDERSON.

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Contents

Plates I-XII.

Part I. Paob

I. Introduction 4

II. Historical Review 6

III. Purpose OP THE Paper lo

IV. Stratigraphy of the Cretaceous 12

1. Basement Complex 12

2. The Sacramento Valley 14

3. The Oregon Basin 17

4. British Columbia 18

5. Southern Occurrences 20

6. Correlation 21

^ V. Faunal Changes of the Cretaceous 22

'I- Recognized Diversity 22

2. Horizons Distinguished 24

1 The Chico Epoch 24

The Horsetoivn Epoch 40

Tlie Paskenta Horizon 43

The SuthKnoxi/ille Horizon 47

VI. Disturbances OF THE Period 48

I. Distribution of the Horsetown Beds 48

I- 2. The Chico-Knoxvtlle Unconformity 50

3. The Peridotitb Intrusions 53

4. The Chico Overlap 54

VII. Correlation OF Deposits 55

1. The Sacramento Sections 56

2. Equivalents of the Chico 56

3. Equivalents OF THE Horsetown 63

4. Equivalents of the Knoxville 65

5. Cordilleran Oscillations 67

VIII. Summary and Conclusions 68