The Red Bluff PedimentA Datum Plane For Locating 

Quaternary Structures in the 

Sacramento Valley, California 


Frontispiece. High-altitude oblique aerial photograph of the northern Sacramento Valley. Sutter Buttes are in 

the lower center. The Red Bluff pediment is outlined along the northern valley margin. 
The Red Bluff PedimentA Datum Plane For Locating 

Quaternary Structures in the 

Sacramento Valley, California 

By EDWARD j. HELLEY and CHERYL JAWOROWSKI 

U. S. GEOLOGICAL SURVEY BULLETIN 1628 
DEPARTMENT OF THE INTERIOR 

DONALD PAUL HODEL, Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

UNITED STATES GOVERNMENT PRINTING OFFICE: 1985 

For sale by the 

Distribution Branch, Text Products Section 

U.S. Geological Survey 

604 South Pickett St. 

Alexandria, VA 22304 

Library of Congress Cataloging in Publication Data 

Helley, Edward John, 1939-

The Red Bluff pediment-a datum plane for locating 

Quaternary structures in the Sacramento Valley, 

California. 

(U.S. Geological Survey Bulletin 1628) 

Includes bibliographic references. 

Supt. of Docs. no. I 19.3: 1628. 

1.Rock deformation-California-Sacramento River 

valley-maps. 2. Pediments (geology)-CaliforniaSacramento River Valley-maps. 3. Geology, 

stratigraphic-Quaternary. 4. Erosion-CaliforniaSacramento River valley. 5. Computer graphics. 

I. Jaworowski, Cheryl. II. Title. Ill. Series: 

United States. Geological Survey.Bulletin 1628. 

QE75.B9 no. 1628. 557.3s 84--600205 

[QE604] [551.8'7'097945] 
CONTENTS 

Abstract 1 

Introduction 1 

Red Bluff pediment 1 

Structure 6 

Conclusion 6 

References 6 

FIGURES 

Frontispiece-High-altitude oblique aerial photograph of the northern Sacramento 

Valley 

1. Photograph showing Red Bluff pediment gravels truncating Tehema 

Formation 2 

2. Sketch map of the Sacramento Valley showing distribution of remnants of the 

the Red Bluff pediment in spatial relation to major late Cenozoic structural 

features 3 

3. Photograph of Red Bluff pediment gravels showing hardpan 4 

4. Photograph of Red Bluff pediment surface south of Red Bluff on Interstate 

Highway 5 5 

5. Geologic map of part of the Vina 7 .5-minute quadrangle 5 

6. Simplified geologic map of the Corning 15-minute quadrangle 7 

7. Structure contour map drawn on the Red Bluff pediment in the Corning 15-

m inu te quadrangle 8 

8. Structure contour map drawn on the Modesto Formation in the Corning 15-

minute quadrangle 9 

9. Residual structure contour map drawn on the Red Bluff pediment in the 

Corning 15-minute quadrangle 10 

10. Structure contour map drawn on the Red Bluff pediment in north-central 

Sacramento Valley 11 

11. Structure contour map drawn on the Red Bluff pediment in the northeast 

corner of the Fruto NE quadrangle 12 

v 
Any use of trade names and trademarks in this publication is for descriptive 

purposes only and does not constitute endorsement by the U.S. Geological Survey. 
The Red Bluff Pediment-A Datum Plane for 

locating Quaternary Structures in the 

Sacramento Valley, California 

By Edward J. Helley and Cheryl Jaworowski 

Abstract 

Throughout much of the Sacramento Valley, 

California, we have mapped an erosion surface of low 

relief and great regional extent that is bet ween 0.45 and 

1.08 milli?n years old. This surface, which is mantled 

by 1 to 10 meters of bright-red sandy gravel of the Red 

Bluff Formation, records the Quaternary expression of 

late Cenozoic folding and faulting. The erosion surface 

(the Red Bluff pediment) was formed by lateral 

planation, probably when through-flowing drainage was 

impeded during a relatively arid climate. Where it is 

exposed by down-cutting streams, the erosion surface 

can be reconstructed by contouring elevations at the 

base of the overlying gravel. If the surface was 

undeformed, we would expect a map showing smooth 

slopes toward the local base level, the Sacramento 

River. For the Red Bluff pediment to be useful as a 

structural datum, the original slope of the erosion 

surface must be determined. To approximate this 

original slope, the contours of the upper surface of the 

upper member of the Modesto Formation (14,000 to 

26,000 yrs B.P.), which slopes toward the Sacramento 

River, were subtracted from the contours on the Red 

Bluff pediment. The upper surface of the Modesto 

shows no deformation, only a simple slope toward the 

Sacramento River. We contoured the Red Bluff 

pediment in the Corning area, where it is known to be 

deformed into two domes. Contours drawn .on the upper 

surface of the Modesto in the same area were 

subtracted from those drawn on the Red Bluff 

pediment. The residual contour map shows two domes, 

as well as a possible northwest-trending fault that 

separates the domes left laterally. The deformation is 

very similar to that shown by contours along the 

subsurface gas-producing sands of the Tehama 

Formation. Where sufficient data points exist, we have 

contoured the Red Bluff pediment elsewhere, using a 

computer graphics system, and have found similar 

results: the pediment appears deformed. This 

deformation must postdate the erosion surface; that is, 

it must be younger than 0.45 million years. The 

deformation may reflect deeper structures, and, if so, 

these techniques provide a rapid, practical, and 

inexpensive exploration tool. 

INTRODUCTION 

The distinct bright-red gravels in and around the 

town of Red Bluff were named the Red Bluff Formation 

by Diller (1894). He proposed that these gravels 

represented evidence of late Tertiary uplift of the 

Coast Ranges. Later, Bryan (1923) recognized the more 

widespread occurrence of the Red Bluff, and he showed 

that it was deformed at the Corning Domes, Chico 

monocline, and Hungry Hollow fault, today called the 

Dunnigan Hills and Zamora faults. During ground-water 

studies in the Sacramento Valley, Olmsted and Davis 

(1961) recognized that the Red Bluff truncated the 

underlying Tehama and Tuscan Formations regionally. 

They also noted that the maximal soil profile developed 

on the Red Bluff forms hardpans which are aquicludes, 

preventing the percolation of surface waters into the 

subsurface reservoir. The hardpans form ledges which 

have aided in the mapping of the Red Bluff Formation. 

The full extent of the Red Bluff throughout the 

Sacramento Valley has recently been mapped by Helley 

and Harwood (1983). 

RED BLUFF PEDIMENT 

Pediments are recognized as gently sloping rockfloored erosion surfaces or plains of low relief. They 

may also be cut across older alluvium. They develop by 

subaerial agents, mostly running water in arid or 

semiarid regions, usually at the foot of an abrupt and 

receding mountain front. Pediments are commonly 

covered by a thin veneer of locally derived alluvium in 

transit across the surface. 

Pediment development, today, appears confined to 

arid and semiarid environments with closed or impeded 

drainage, such as the Great Basin and parts of the 

Colorado Plateau (Rich, 1935; Howard, 1942; Tuan, 

1959; Hunt, 1969). Most previous workers agree that a 

primary mechanism for development is lateral planation 

by streams and rills with a fixed base level (Bryan, 1922; 

Howard, 1942). Denny (1967) believed pediments can 

also develop in humid as well as arid environments and 

cited examples in the Eastern United States. It may be 

that impeded drainage is more important than climate 

for controlling pediplanation. 

1 
Figure 1. Outcrop of gravels of the Red Bluff Formation (Qrb) truncating the Tehama Formation (Tte), south side 

of State Highway 36 about 6 miles (10 km) west of the city of Red Bluff. View is to the south. 

In this study we have interpreted the Red Bluff 

Formation as the sedimentary cover overlying a 

pediment. Our interpretation is based on the following 

field observations: (1) The Red Bluff is a thin veneer of 

bright-red gravels whose lower contact bevels the 

various underlying units (fig. 1). (2) This lower surface 

has very low relief and large regional extent. The 

coarse poorly sorted Red Bluff gravels represent an 

abrupt departure from the flow regimes which deposited 

the underlying finer grained better sorted sediments of 

the Tehama, Tuscan, and Laguna Formations. (3) 

Lithologies of Red Bluff clasts faithfully reflect local 

provenances. For example, the gravels west and 

southwest of Redding are dominantly composed of rock 

types exposed in the Klamath Mountains, such as 

metachert, polycycle siliceous grit, greenstone, and 

granitic rocks. Along the west side of the Sacramento 

Valley and in the Coast Ranges foothills the clasts are 

derived from the Great Valley sequence and the 

Franciscan Complex. Graywacke, mudstone, siltstone, 

and chert with visible radiolarians are common clasts. 

On the northeast side of the valley, east of Redding and 

south to Chico, the Red Bluff gravels are exclusively 

andesite and basalt derived from the Tuscan Formation 

and associated volcanic rocks, although some 

metamorphic rocks and vein quartz may be present. 

South of Chico along the east side of the valley, clasts 

2 

in the Red Bluff reflect western Sierra Nevada 

lithologies. They consist of metamorphic and granitic 

rocks, resistant quartz or quartzite, and cherts of 

various colors usually veined and highly fractured with 

no distinct radiolarians; all are set in a matrix of 

arkosic sand. 

Figure 2 shows the distribution of the Red Bluff 

pediment in relation to source terranes and to the major 

late Cenozoic structural features of the Sacramento 

Valley. The pediment appears best preserved on 

structural highs, as in the Dunnigan Hills near Cache 

Creek and in the area north of Willows. 

The Redding and Corning soil series are 

characteristically developed on the Red Bluff pediment 

throughout the Sacramento Valley. These soils are very 

strongly developed xeralfs (noncalcic brown soils), 

similar to those forming today on Quaternary deposits 

throughout the valley, and attest to the semiarid 

climate of the past (Marchand and Allwardt, 1981). The 

Redding soil series is differentiated from the Corning 

soil series by the presence of a thickduripan that tends 

to impede surface-water percolation, resulting in 

standing water during the rainy season. The duripans 

aid in mapping the pediment cover, as they form a 

topograhically distinct ledge over the underlying 

sedimentary deposits (fig. 3). The surface upon which 

both the Redding and Corning soils are developed also 
40' 

39' 

(") 

0 

; 

" Valley margin 

122' 

\ 

D 

EXPLANATION 

REMNANT OF RED BLUFF 

PEDIMENT 

--- FAULT 

---+- ANTICLINE, SHOWING PLUNGE 

---+- SYNCLINE, SHOWING PLUNGE 

z 

m 

< 

)> 

0 

)> 

io 

20 

20 MILES 

40 KILOMETERS 

N 

I 

Figure Z. Sketch map of the Sacramento Valley showing the distribution of remnants of the Red 

Bluff pediment and the major late Cenozoic structural features known from subsurface and surface 

mapping (Harwood and Helley, 1982). 

3 
Figure 3. Pediment gravels of the Red Bluff Formation, showing hardpan (arrow). View is to north on Palermo 

Road south of Oroville. Here the Red Bluff truncates the Laguna Formation. 

displays the unique "mima mound" or hog-wallow 

microrelief (fig.4; Arkley, 1962, p.28). This distinct 

microrelief also aided in mapping the Red Bluff 

pediment. 

The age of the Red Bluff Formation is fairly well 

established on the basis of the relative positions of 

several formations along part of the Chico monocline 

(fig. 5; Harwood and others, 1981). The olivine basalt of 

Deer Creek, 1.08+0.16 m.y. old (Harwood and others, 

1981) underlies the Red Bluff, whereas the Rockland ash 

bed, 0.45 m.y. old (Meyer and others, 1980; SarnaWojcicki and others, 1984, oral commun., 1981), overlies 

it in numerous places (Helley and others, 1981). 

Therefore, the Red Bluff Formation developed over a 

one-half million year interval, or less. In the San 

Joaquin Valley to the south, Frink and Kues (1954) 

interpreted the Corcoran Clay Member of the Tulare 

and Turlock Lake Formations to be a lacustrine deposit 

of regional extent that is the same age as the Red 

Bluff. Janda and Croft (1967) published an age of 0.6 

m.y. for the Friant Pumice Member of the Turlock Lake 

Formation which lies conformably on the Corcoran. 

Page and Bertoldi (1982) described lacustrine clays in 

the Sacramento Valley which are identical to the 

Corcoran in terms of diatom flora and mineralogy. 

Page and Bertoldi (1982) also recovered a pumiceous ash 

sample from a core northeast of the Dunnigan Hills near 

Zamora. This ash is stratigraphically above the 

Corcoran-like clays and is chemically identical to the 

4 

Rockland ash bed (C. E. Meyer, written commun., 

1982). We tentatively correlate the clay beneath the 

Rockland ash bed in the Sacramento Valley with the 

Corcoran Clay Member of the San Joaquin Valley on the 

basis of similar flora and mineralogy. We conclude that 

the through-flowing drainage from the Sacramento 

Valley was impeded at this time by the presence of a 

large, but not necessarily deep, lake that facilitated the 

pediplanation process. This process probably began at 

the southern end of the Central Valley, progressed 

northward, and may have operated for the entire period 

from 1.08 to 0.45 m.y. ago. During that time there was 

no outlet through the Carquinez Straits as we know it 

today. 

For our purposes, to assess late Cenozoic 

deformation, the Red Bluff pediment is the most 

important datum in the Sacramento Valley. We use the 

pediment as a structural datum because (1) pediments 

are relatively flat or gently sloping planimetric 

surfaces, (2) the age range of the pediment is well 

established, having developed over a reasonably short 

geologic time, (3) exposures are widespread and 

generally occupy the topographically highest part of the 

valley, (4) because of the strong soil profile with 

duripans, deposits on the pediment are resistant enough 

to preserve the previously deformed surface, and (5) 

the deformation of the pediment in the Corning and 

Dunnigan Hills areas is already documented. 
Figure 4. Red Bluff pediment surface south of Red Bluff along Interstate Highway 5. View is to northeast with 

Tuscan Buttes in center of photograph. Note hog-wallow microrelief on pediment surface. 

40' 

122' 

Ora 

d~ 

Orb 

Om 

EXPLANATION 

~ ALLUVIUM (Holocene) 

~ BASIN DEPOSITS (Holocene) 

G MODESTO FORMATION (Pleistocene) 

~ RIVERBANK FORMATION (Pleistocene) 

~ ROCKLAND ASH BED (Pieistocene)-Age is 0.45 m.y. 

G RED BLUFF FORMATION (Pleistocene) 

IQbdcl 

~ 

OLIVINE BASALT OF DEER CREEK (Pleistocene)-

Age is 1.08±0.16 m.y. 

8 OLDER GRAVEL DEPOSITS (Pleistocene and Pliocene) 

TUSCAN FORMATION (Pliocene). Locally, divided into: 0 UNITC 

~UNITS 

Figure 5. Geologic map of part of the Vina 7 .5-minute quadrangle, California (from Harwood and others, 1981). 

5 
STRUCTURE 

Structure contours on the pediment surface were 

generated by a collection of Fortran subroutines that 

produce graphic representations of three-dimensional 

continuous surfaces in the form of contour maps or' 

perspective views using the Surface Display Library 

running under the Multics Operating System (see Mark 

and Newman, 1981). We began in the Corning area of 

the north-central Sacramento Valley because of the 

abundance of Red Bluff exposures as well as prior 

knowledge of the deformation there. Younger alluvial 

deposits of the Riverbank and Modesto Formations are 

present in cut-and-fill positions below the Red Bluff 

pediment and provide surfaces for comparison with the 

pediment. Base-level control was the Sacramento 

River, which flows southward through the area. A 

simplified geologic map of the Corning area (fig. 6) 

shows the Red Bluff underlying the dissected alluvial 

fans that originated from the area of the Chico 

monocline to the northeast. The Red Bluff also covers 

the two hills in the center of the quadrangle, known as 

the north and south Corning Domes (Sacramento 

Petroleum Association, 1962, p. 102), and the east-westtrending l~near hills along the west side of the 

quadrangle. Dissection has produced as much as 100 

feet (30 meters) of relief, thus providing the many data 

points necessary for machine contouring. Bugry (1 981) 

provided a historical review of computer contour 

methods. He decribes two methods, one that has an 

intervening step of gridding the data points before 

contouring and the other that does not (Bugry, 1981, p. 

209). We used the procedure of intervening gridding. 

Elevations at the base of the Red Bluff Formation were 

digitized using a Tektronix Graphics terminal with 

digitizing board. 

If the Red Bluff pediment surface in the Corning 

quadrangle was undeformed, we would expect the 

resulting contour map to display subparallel lines sloping 

east and west toward the Sacramento River, the base 

level. However, the resulting map of the Corning 

quadrangle clearly shows the north and south Corning 

Domes by closed contours (fig. 7). The contours also 

suggest that the domes may be offset along a 

northwest-trending fault coincident with the linear 

outcrop pattern along the west edge of the north 

dome. Most of the contours in the northeast corner of 

the quadrangle show simple subparallel lines sloping 

toward the Sacramento River. This contour map (fig. 7) 

shows that the original slope of the pediment surface 

has been distorted. Because we did not know what the 

original slope was, we estimated it by preparing a 

contour map on the top of the upper member of the 

Modesto Formation (14,000 to 26,000 yrs B.P., Marchand 

and Allwardt, 1981). That contour map (fig. 8) shows 

fairly simple subparallel lines sloping toward the 

Sacramento River. The contours on the Modesto 

Formation were subtracted by computer from those on 

the Red Bluff pediment (fig. 7) to produce a map (fig. 9) 

showing the residual contours on the pediment surface. 

The Corning Domes show 40 to 50 feet (12-15 m) 

of structural closure. Other closed contours are shown 

southwest of the Corning area, with similar amounts of 

structural closure but with an east-west orientation. 

Because these apparent folds were unexpected, we 

expanded the mapping and contouring to cover 12 

6 

adjacent 7 .5-minute quadrangles (fig. 10). Again the 

Corning Domes stand out, but several others also 

appear, in the Black Butte Dam, Kirkwood, and 

Henleyville quadrangles. Note the courses of both Stony 

Creek and Thomes Creek. Stony Creek cuts through the 

Lovejoy Basalt at an apparent structural high at Black 

Butte and flows southeasterly toward its confluence 

with the Sacramento River. Thomes Creek, on the 

other hand, flows northeasterly, against the regional 

drainage, to the Sacramento River. The courses of both 

streams were apparently controlled or at least diverted 

by the Corning Domes. Stony Creek also appears 

antecedent to the structure at Black Butte, where the 

creek has taken its course through the resistant Lovejoy 

Basalt rather than cutting through the softer and easily 

erodible Tehama Formation. We enlarged the 

contouring for the northeast quarter of the Fruto NE 

quadrangle (fig. 11), an area near where Harwood and 

Helley (1982) projected the trace of the Willows fault 

from subsurface data and from outcrops of the Lovejoy 

Basalt. This map shows a good contrast between 

contours that show simple sloping and those that 

apparently reflect a small tight east-plunging fold that 

is probably related to drag on the Willows fault. 

CONCLUSION 

Erosional pediment surfaces can be used to assess 

late Cenozoic deformation, especially where the 

pediment surface has closed contours and the folds are 

recent. In the Sacramento Valley deformation postdates 

the Red Bluff pediment surface and predates the upper 

surface of the Modesto Formation; it is less than 0.45 

m.y. old. Many of the surface folds overlie deeper 

subsurface structures, which suggests continuing longterm deformation. Unfortunately, the Red Bluff 

Formatiqn, which overlies the pediment, has been 

stripped away in many places in the Sacramento Valley, 

leaving an insufficient number of data points to 

contour. We suggest that where pediments are 

preserved this methodology is a useful and rapid 

exploration tool and an inexpensive procedure for 

generalized mapping of regional structure. 

REFERENCES 

Arkley, R. J., 1962, The geology, geomorphology and 

soils of the San Joaquin Valley in the vicinity of the 

Merced River, California: California Division of 

Mines and Geology Bulletin 182, p. 25-33. 

Bryan, Kirk, 1922, Erosion and sedimentation in Papago 

County, Arizona: U.S. Geological Survey Bulletin 

730, p. 19-91. 

___ 1923, Geology and ground-water resources of 

Sacramento Valley, California: U.S. Geological 

Survey Water-Supply Paper 495, 285 p. 

Bugry, R., 1981, Computer contouring packages: an 

historic view: Bulletin of Canadian Petroleum 

Geology, v. 29, no. 2, p. 209-214 • . 

Denny, C. S., 1967, Fans and pediments: American 

Journal of Science, v. 265, p. 81-105. 

Diller, J. S., 1894, The Tertiary revolution in the 

topography of the Pacific coast: U.S. Geological 

Survey Fourteenth Annual Report, Part II, p. 397-

434. 
122°15' 

40°00' ,....,...,......,...,..,...,...,....,...,..,.., 

EXPLANATION 

Lj:::;~;.ii ::::d ALLUVIUM (Holocene) 

[i .. O.rll .• i I MODESTO FORMATION (Pleistocene) 

RIVERBANK FORMATION (Pleistocene) 

~ RED BLUFF FORMATION (Pleistocene) 

I 

4 

I 

4 MILES 

I 

6 KILOMETERS 

Figure 6. Simplified geologic map of the Corning 15-minute quadrangle, California, 

showing distribution of Quaternary deposits. 

7 
122°30' 

40°00' 

MILES 

I 

4 KILOMETERS 

-200--

STRUCTURE CONTOURS-Drawn on top 

of Red Bluff pediment. Contourinterval 

10 feet. Datum is mean sea level. 

+ , control point 

mooo· 

Figure 7. Structure contour map of the Red Bluff pediment in part of the Corning 15-minute quadrangle, Calif. 

Shaded areas show outcrop distribution of the Red Bluff Formation. The northeast side appears undeformed, but 

the central and western areas appear domed and folded. 

8 
122'15' 122'00' 

40'00' ,-------,------r---.---r------r-=r-..---.---....---=-.,...--,---.-....--r~----.,--y-------..-----=---r-----:--:--r--r---r-r-T"T--.-'il7""":"'t""T---,r-----r---, 

0 

I 'I 

0 

I 

2 

I 

3 

2 

I I 

4 

3 MILES I 

I 

5 KILOMETERS 

EXPLANATION 

STRUCTURE CONTOURS-Drawn on top of Modesto Formation. 

Contour interval 10 feet. Hachures indicate depressions. Datum 

is mean sea level. + , Control point 

Figure 8. Structure contour map of the top of the Modesto Formation in the Corning 15-minute quadrangle, Calif. Shaded areas show outcrop distribution of the Modesto Formation. 

9 
122'30' 122'00' 

40'oo· ,--~-rr--r----r---,--~""""~~-:A'I~r-/T~~::-~~mfr«i~~~rr.71-x-:---wn 

MILES 

I 

4 KILOMETERS 

Q RE~DUALSTRUCTURECONTOURSDrawn by subtracting contours on the 

Modesto Formation from those on the Red 

Bluff pediment. Contour interval 10 feet. 

Hachures indicate depressions. Datum is 

mean sealevel. + control t 

Figure 9. Residual structure contour map of the Red Bluff pediment in the Corning 15-minute quadrangle, Calif. 

Contours on the top of the Modesto Formation (fig. 8) were subtracted from those on the pediment (fig. 7). 

Shaded area shows distribution of the Red Bluff Formation. Maximum closure is about 50 feet (15.5 m). 

10 
122'22'30' 122'00' 

40'07'30' r--------------r-------------.----,-----------------, 

2 4 MILES 

~~~~~L~~~~~-~jj 

Orland 

-·-Joo3 6 KILOMETERS 

Hamilton City 

EXPLANATION 

STRUCTURE CONTOURS-Drawn on top 

of Red Bluff pediment. Contour interval 

20 feet. Datum is mean sea level. Dots are 

control points. 

Figure 10. Structure contour map of the Red Bluff pediment, corrected for original 

slope, for 12 7 .5-minute quadrangles in the north-central Sacramento Valley, Calif. 

Quadrangle name is in lower right corner of each one. 

11 
12 

0 2 MILES 

0 2 3 KILOMETERS 

EXPLANATION 

STRUCTURE CONTOURS-Drawn on top of Red Bluff 

pediment. Contour interval 10 feet. Datum is mean sea 

--250- level 

Figure 11. Structure contour map of the Red Bluff pediment, corrected for original slope, in the 

eastern part of the Fruto NE quadrangle, Calif. Outcrop area of the Red Bluff Formation shown in 

shaded pattern. Closed contour shows east-west-trending fold possibly related to displacement on the 

Willows fault. 
Frink, V. W., and Kues, H. A., 1954, Corcoran Clay, a 

Pleistocene lacustrine deposit in the San Joaquin 

Valley, California: American Association of 

Petroleum Geologists Bulletin, v. 38, p. 2353-2371. 

Harwood, D. S., and Helley, E. J ., 1982, Preliminary 

structure contour map of the Sacramento Valley, 

California, showing major Late Cenozoic structural 

features and depth to basement: U.S. Geological 

Survey Open-File Report 82-737, scale 1:250,000. 

Harwood, D. S., Helley, E. J., and Doukas, M.P., 1981, 

Geological map of the Chico monocline and 

northeastern part of the Sacramento Valley: U.S. 

Geological Survey Miscellaneous Investigations Map 

I-1238, scale 1:62,500. 

Helley, E. J ., and Harwood, D. S., 1983, Geologic map of 

the Cenozoic deposits of the Sacramento Valley and 

Sierran foothills (abs.) : American Association of 

Petroleum Geologists Pacific Section Meeting, 58th, 

Sacramento, Calif., 1983, Program and Abstracts. 

Helley, E. J ., Harwood, D. S., Barker, J. A., Griffin, E. 

A., 1981, Geologic map of the Battle Creek fault 

zone, northern Sacramento Valley, California: U.S. 

Geological Survey Miscellaneous Field Studies Map 

MF-1298, scale 1:62,500. 

Howard, A. D., 1942, Pediment passes and the pediment 

problem: Journal of Geomorphology, v. 5, no. 1, p. 

3-31, and no. 2, p. 95-136. 

Hunt, C. B., 1969, Geologic history of the Colorado 

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669, p. 59-130. 

Janda, R. J ., and Croft, M. G., 196 7, The stratigraphic 

significance of a sequence of noncalcic brown soils 

formed on the Quaternary alluvium of northeastern 

San Joaquin Valley, California, in Morison, R. B., and 

Wright, H. E., eds., Quaternarysoils: International 

Association of Quaternary Research, VII Congress, 

Reno, Nevada, Proceedings, v. 9, p.158-190. 

Marchand, D. E., and Allwardt, Alan, 1981, Late 

Cenozoic stratigraphic units, northeastern San 

Joaquin Valley, California: U.S. Geological Survey 

Bulletin 14 70, 70 p. 

Mark, R. K., and Neuman, E. B., 1981, User oriented, 

interactive Multics computer programs to create 

grid cell, contour, and perspective maps using 

Surface Display Library: U.S. Geological Survey 

Open-File Report 81-513, 49 p. 

Meyer, C. E., Woodward, M. J., Sarna-Wojcicki, A. M., 

and Naesar, C. W., 1980, Zircon fission-track age of 

0.45 million years on ash in the type section of the 

Merced Formation, west-central California: U.S. 

Geological Survey Open-File Report 80-1071, 6 p. 

Olmstead, F. H., and Davis, G. H., 1961, Geologic 

features and ground-water storage capacity of the 

Sacramento Valley, California: U.S. Geological 

Survey Water-Supply Paper 1497, 241 p. 

Page, R. W., and Bertoldi, G. L., 1982, A Pleistocene 

diatomaceous clay and a pumiceous ash: California 

Geology, v. 36, no. 1, p. 14-20. 

Rich, J. L., 1935, Origin and evolution of rock fans and 

pediments: Geological Society of America Bulletin, 

v. 46, no. 6, p. 999-1024. 

Sacramento Petroleum Association, 1962, The Corning 

and South Corning gas fields, California, ..!!!, Bowen, 

0. E., Jr., ed., Geologic guide to the gas and oil 

fields of northern California: California Division of 

Mines and Geology Bulletin 181, p. 101-102. 

Sarna-Wojcicki, A. M., Meyer, C. E., Bowman, H. R., 

Hall, N. T., Russell, P. C., Woodward, M. J., and 

Slate, J. L., 1984, Correlation of the Rockland ash 

bed, a mid-Pleistocene stratigraphic marker in 

northern and central California and western 

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Tuan, Yi-Fu, 1959, Pediments in southeastern Arizona: 

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