Reconnaissance of the Geomorphology

and Glacial Geology of the

San Joaquin Basin, Sierra Nevada

California

GEOLOGICAL SURVEY PROFESSIONAL PAPER 329
Reconnaissance of the Geomorphology

and Glacial Geology of the

San Joaquin Basin, Sierra Nevada

California

By FRANCOIS E. MATTHES

GEOLOGICAL SURVEY PROFESSIONAL PAPER 329

A region of exceptional 

interest to the geomorphologist

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1960

CONTENTS

Foreword._____________________________

Abstract_ _ ____________________________

Introduction. __________________________

Itinerary of expeditions.____________

Investigations subsequent to fieldwork. 

Acknowledgments. _ _________________

Geographic sketch______________________

Location and extent of area-_________

Drainage and topography, ________

Climatic conditions.________________

Life zones and vegetation.___________

Economic and social use ____________

Rocks _________________________________

Granitic rocks_.________________________________

Jointing and exfoliation______________________

Modes of weathering. ______________________

Metamorphic rocks_ _______________________

Volcanic rocks.. _______________________________

Geomorphology_ _ ________________________________

Comparison of sections of the Sierra west slope.____

Suitability of the San Joaquin Basin for geomorphologic analysis____________________________

Summary of conclusions concerning the Yosemite 

region_ ______________________________________

Geomorphology of the San Joaquin Basin__________

Description of geomorphologic features. _______

Foothill belt_____-_-__-_-___--_--______

San Joaquin Canyon and its main branches. 

Hanging valleys-_______________________

Intercanyon uplands-__---_-____-__-____

Longitudinal and transverse crests-_______

Tabular summits-______________________

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Geomorphology Continued

Geomorphology of the San Joaquin Basin Con. 

Description of geomorphologic features Con.

Main drainage divide__________________ 38

Relation of main drainage divide to escarpment on east side of range-____________ 39

Interpretation of geomorphologic features______ 39

Erosion surfaces._______________________ 40

Hanging valleys________________________ 41

Restored Miocene and Pliocene profiles____ 41

Significance of pattern of ridges and valleys. 44 

Relation of main drainage divide to escarpment on east side of range-____________ 45

Glaciation_ _________---_-_-______________---_--___- 46

Differentiation of moraines and correlation of glacial

stages. ______________________________________ 48

Glaciers of the pre-Wisconsin stages.______________ 49

Middle Fork glacier______-_-_--___-_-_--___- 50

South Fork glacier._________________________ 50

Central icefield.____________________________ 51

Lower San Joaquin glacier___________________ 52

Glaciers in Big Creek basin._________________ 52

Depth of canyon cutting since earlier glaciation_ 53 

Glaciers of the Wisconsin stage ___________________ 53

Middle Fork glacier_________________________ 54

South Fork glacier._________________________ 55

Glaciers on Kaiser Ridge____________________ 57

Granite Creek glacier,_______-_--_--_-_-___ 58

Glaciers in Chiquito Creek basin______________ 58

Glaciers in the Big Creek basin_______________ 58

Selected references-___________-___-__----_-____-____ 59

Index_____________________________________________ 61

ILLUSTRATIONS

PLATE 1. Map of ancient glaciers of the San Joaquin Basin, Sierra Nevada, Calif ______ __________________-------_ In

2. Longitudinal profile of San Joaquin River__________-__-______________-_____-__-___-------------__ In

FIGURE 1. Index map showing location of San Joaquin Basin_ ____________________________________

2. Drainage map of San Joaquin Basin and surrounding region____________________________

3. Profile across Sierra Nevada, from Big Sandy Valley to Owens River_____________________

4. Profile from North Fork across the crest of the Sierra Nevada,_______________-_-------_-

5. Geologic map of San Joaquin Basin and surrounding region.____________________________

6. View across the South Fork of the San Joaquin River____________-______-_--_--___---_-

7. Squaw Dome, from the east___-_________________-_____________-_____---------_------

8. Imperfect domes on Chiquito Ridge__________________________________________________

9. Ice-truncated columns of basalt on the Devils Postpile___--____________----_--_~--_--_-

10. Rainbow Falls on the Middle Fork of the San Joaquin River____________________________

11. Idealized profile showing features produced by successive cycles of erosion in Sierra Nevada12. Section through Table Mountain region, Sierra Nevada__________________-_-__----_--_-_

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VI CONTENTS

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FIGURE 13. View down San Joaquin Canyon______________________________________-------------_--------_-------- 26

14. View in San Joaquin Canyon_______________________________-_______--_--------------_-------------- 26

15. View up San Joaquin River toward Balloon Dome._______________________-____-_-__-_-_-_--__-_--_----- 27

16. View southeastward up the South Fork of the San Joaquin River.__________________________^_________--__ 28

17. Evolution Valley from the South Fork of the San Joaquin River____________-__--_---_-_-_--_________---_- 30

18. Falls of Stevenson Creek on east side of San Joaquin Canyon. _______________________-_______-----___---- 31

19. Big Creek Cascade from below Huntington Lake____________________________-______-_-___-------------- 31

20. View down Evolution Valley.______^_____________________________-_--_-_-_----_--------.--------^----- 34

21. Well-preserved remnant of the Miocene erosion surface south of Evolution Valley__________ ____-________---- 35

22. View southeastward along Glacier Divide._____-________________________----------_---------_----_----- 35

23. Panorama southward from a point near outlet of Evolution Lake___________________--___-----------_----_ 36

24. View southeast across Twin Lakes.___________________________________________________________________ 37

25. Mount McGee summits and cirques of McGee Creek____________________-_______________---._-_----_----- 37

26. Goddard Canyon and Mount Goddard_______-___-_____-_________-____-_-------_-----__-------_-------- 37

27. Mount Darwin and Mount Wallace from Evolution Basin. ______________________________________________ 38

28. Hackly surface produced by glacial plucking________________________________-_-_-__-_______------__---- 47

29. Valley floor modified by glacial plucking__ _____________________________________________________________ 47

30. Details of ice-scoured rock floor of Evolution Basin, near Sapphire Lake,__________________________________ 48

31. Crescentric gouges near base of Mount Huxley_______-_________-________--_----------------------__---- 49

32. Perched erratic boulder south of Junction Bluffs._______________________________________________________ 51

33. Remarkable imitation of a perched erratic boulder of granite, produced wholly by weathering in place. _______ 52

34. Chiquito Creek basin, north of Placer Ranger Station,__________________________________________________ 53

35. Gorge of Chiquito Creek________________________________________________________________________^___- 53

36. Residual granite shafts between Granite Creek and Middle Fork of the San Joaquin River___________________ 54

37. Other residual granite shafts between Granite Creek and Middle Fork of the San Joaquin River______________ 54

38. Thousand Island Lake, in cirque of the Middle Fork of the San Joaquin River_____________________________ 54

39. Cirque, northwest of Selden Pass____________________________--__-______--_-----_--_--_---_-_-_------ 55

40. Typical roches moutonne'es, Blaney Meadows _________________________________________________________ 55

41. Moraine of the later glaciation in lower Vermilion Valley________________________________________________ 56

42. Lateral moraine of the later glaciation near mouth of Vermilion Valley._________________--___---_---__---_ 56

43. View eastward up canyon of Mono Creek._____________________________________________^_______________ 56

44. Mono Meadow in the valley of the South Fork, San Joaquin River_______________________________________ 57

45. Erratic boulder of granite near Twin Lakes_____________________________-_----_-_--_-______________---- 58

46. Glacial erratic on floor of Mono Creek Canyon.__________________________________^_____-.-^---__--__--_- 58

47. Black Peak, a volcanic knob near South Fork of Big Creek_ _____________________________________________ 59

48. View from the summit of Black Peak looking down Long Meadow________________________________________ 59
RECONNAISSANCE OF THE GEOMORPHOLOGY AND GLACIAL GEOLOGY 

OF THE SAN JOAQUIN BASIN, SIERRA NEVADA, CALIFORNIA

By FRANQOIS E. MATTHES

ABSTRACT

Reconnaissance of the San Joaquin Basin, situated in the 

central part of the west slope of the Sierra Nevada, California, 

was undertaken in order to extend southeastward the studies 

made earlier in the Yosemite region, and to test the soundness of conclusions reached in the Yosemite region, regarding 

the geomorphologic development and the glaciation of that 

area and to determine their bearing on the history of the 

Sierra Nevada as a whole.

For these purposes the San Joaquin Basin is, in several 

respects, the most revealing of the drainage basins of the 

west slope of the Sierra Nevada. In it, the erosional features are unobscured by volcanic flows except locally. Also, 

the granitic rocks are exceptionally extensive, and their prevailing massive character has profoundly influenced the topography. For example, the San Joaquin Canyon is consistently 

narrow, and exhibits neither anomalous Yosemite-like widenings nor, for the most part, the unusual sculpturing characteristic of the yosemites.1 Also, the resistant nature of the massive granitic rocks accounts for the preservation of an unusually fine record of the successive cycles of erosion, and an 

extraordinary wealth of clean-cut hanging side valleys. Furthermore, because the granitic rocks are practically continuous 

to the foot of the range, the ancient erosion surfaces and the 

array of hanging valleys likewise extend not merely throughout 

the glaciated upper course of the San Joaquin Canyon but also 

through most of the unglaciated lower course, to within a few 

miles of the foothills.

It should be noted, too, that the San Joaquin River, having 

a southwestward course conformable to the slope of the Sierra 

block, was subjected to the full rejuvenating impulse of each 

tilting movement. Its tributaries, on the other hand, have 

mostly northwesterly or southeasterly courses, at right angles 

to the master stream as well as to the direction of tilting of 

the block. The flow of the tributaries, therefore, was accelerated very little by the tilting of the Sierra block. In this 

contrasting relationship of master stream to tributaries the 

drainage pattern of the San Joaquin Basin is typical for most 

of the basins in the central and southern part of the Sierra 

Nevada, but probably in no other basin is the relationship so 

well shown.

The salient geomorphologic features of the San Joaquin

1 Yosemite comes from "uzumati" or "uhumati," which in the language of the Southern Miwoks meant "grizzly bear." It is said to 

have been originally the name of the tribe of Indians who inhabited 

the Yosemite Valley, or at least of that part of the tribe which dwelt 

on the north side of the Merced River. The name was given to the 

valley, at the suggestion of Dr. Lafayette Houghton Bunnell, by the 

Mariposa Battalion, the first party of white men to enter the valley, 

in 1851.

Basin may be summarized as follows: The San Joaquin Canyon is essentially a narrow, youthful, branching gorge, which 

has been cut into the floor of a relatively broad, mature valley. 

The mature valley in turn is flanked by extensive undulating 

uplands, with a relief over wide areas not greater than 1,000 

feet. In places, however, the uplands are surmounted by hills, 

mountain groups, and imposing mountain crests trending, in 

most cases, in a northwesterly direction, and having a relief 

of 1,500 to over 2,500 feet, ranges forming a part of the 

so-called High Sierra. At least one mountain crest has peaks 

that bear distinctively tabular summits.

These features are believed to be the products of four partial 

cycles of stream erosion, each initiated by a major uplift. 

They are interpreted as follows:

Expressive of the latest cycle, is the branching gorge or 

inner canyon of the San Joaquin River and its main branches. 

This gorge is regarded as being wholly of Pleistocene origin, 

and is correlated with the "canyon stage" of the Yosemite 

region. The benches and shoulders which flank the Pleistocene 

gorge in the lower and middle reaches of the basin, giving the 

San Joaquin Canyon a 2-storied aspect, are remnants of a 

mature valley developed in a partial cycle of erosion which 

preceded the canyon stage. The maturity of this valley is 

indicated by its broadly flaring cross section and its low, 

smooth gradient (deduced from the extended gradients of the 

lateral valleys that were left hanging in the latest cycle of 

erosion). To have attained its mature character, the valley 

must have required a period several times as long as that 

which was required for the carving of the Pleistocene gorge. 

It may be inferred that the partial cycle of erosion in which 

the valley was developed embraced all, or nearly all, of the 

Pliocene epoch. Accordingly, the Pliocene valley of the San 

Joaquin River may be assigned to the "mountain valley stage" 

of the Yosemite region.

The undulating uplands into which the Pliocene valley has 

been cut are erosion surfaces referable to a still earlier cycle. 

The forms of these uplands are so much more mature than 

those of the Pliocene valley that there is good reason to assign 

for their development a correspondingly greater span of time. 

Furthermore, they are clearly correlative with the uplands of 

the Yosemite region, and are traceable across the divide and 

continuous with the uplands of that region. From paleontological evidence found north of Yosemite Valley, in the Table 

Mountain district between the Tuolumne and Stanislaus Rivers, 

it appears that the Yosemite uplands, representing the broad 

valley stage, are of late Miocene age. Accordingly, the uplands of the San Joaquin Basin are also thought to have been 

produced in a cycle of erosion which began some time back in 

the Miocene and continued until the latter part of that epoch.
GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

Finally, the hills, mountain groups, and mountainous crests 

surmounting the uplands are clearly monadnocks, and the tabular summits (Mount Darwin and Mount Wallace) of the one 

crest are, from the evidence of the great height to which these 

summits rise above the uplands, much older than the Miocene 

erosion surface. These platforms are referable to the most 

ancient erosion surface recognizable in the Sierra Nevada, 

thought to be Eocene in age.

The hanging lateral valleys fall into two tiers or sets, the 

one much higher than the other. Valleys of the upper set are 

hanging with reference to the mature Miocene erosion surface. 

Valleys of the lower set are hanging with reference to the 

Pliocene erosion surface (the flanking benches and shoulders 

of the San Joaquin Canyon). The 2 sets of hanging valleys 

attest to 2 rejuvenations of the master stream induced by 2 

uptiltings of the Sierra Nevada. Valleys of the upper set were 

left hanging as a result of the uplift which initiated the mountain valley stage of erosion during the Pliocene; those of the 

lower set, as a result of the uplift which initiated the canyon 

stage of erosion during the Pleistocene. The 2 sets of hanging 

valleys are analogous to the 2 upper tiers of hanging valleys 

in the Yoseniite region.

By the same method employed in connection with study of 

the Yosemite Valley, the data provided by the hanging valleys 

of the San Joaquin Basin were used to reconstruct the longitudinal profiles of the San Joaquin River and its 2 branches 

for each of the 2 stages of erosion indicated. The abundance 

and distribution of the hanging valleys made possible the 

reconstruction of the former river profiles throughout a much 

longer section than in the case of the Merced, and farther down 

toward the foothills.

The mountain crests surmounting the Miocene erosion surface are features inherited from the system of northwestwardtrending ridges that occupied the place of the present Sierra 

Nevada in Late Jurassic and Cretaceous time. The northwestward-trending valley troughs between these crests similarly are features dating far back into Cretaceous time, and 

still control the drainage pattern of the tributary streams to 

a marked degree.

The main drainage divide, at the head of the San Joaquin 

Basin, does not coincide with the top of the great east escarpment of the Sierra Nevada except at two very short stretches. 

Evidently the divide is an ancient erosional feature, which 

parted northeastward flowing waters from southwestward 

flowing waters long before tectonic movements formed the 

escarpment. The escarpment is probably in large part of early 

Pleistocene origin, and is a feature produced as a result of the 

downfaulting of the Owens Valley graben.

During the Pleistocene epoch, the higher parts of the San 

Joaquin Basin were repeatedly mantled with glaciers. As a 

result, glacial features were superimposed on a landscape 

inherited from Miocene and Pliocene times. For tracing and 

mapping the courses of the ancient glaciers, and for determining their farthest limits, reliance was placed on the testimony 

of glacial deposits rather than on that of sculptural features, 

and a systematic survey was made of the moraines built by 

the individual glaciers. On the glacial map constructed from 

this survey, distinction has been made only between the Wisconsin and pre-Wisconsin stages. However, at several localities the field data appear to warrant future subdivision of the 

Wisconsin moraines into those of early Wisconsin time and 

those of late Wisconsin time, corresponding to the Tahoe and 

Tioga stages of Blackwelder. The pre-Wisconsin moraines are 

in all respects closely similar to those in the Yosemite region,

and are therefore referred to the El Portal stage, believed to 

correspond to Blackwelder's Sherwin stage at the east base of 

the range and thought to be not younger than the Illinoian 

stage of the continental glaciation. No morainal deposits 

belonging to the Glacier Point stage, the earliest stage of 

glaciation recognized in the Yoseniite region, are shown on the 

map but a few small, isolated patches of an ancient moraine 

were discovered in the central part of the basin, and these 

may well be representative of the Glacier Point stage, in view 

of their elevated positions.

The San Joaquin glacier system of the El Portal stage was 

by far the largest system of confluent glaciers in the Sierra 

Nevada, measuring more than 50 miles in length along the 

crest of the range, and 30 to 35 miles in breadth. Of the 1,760 

square miles comprised in the San Joaquin Basin, almost 1,100 

square miles were covered by glaciers. This ice mass, taken 

together with the ice masses in the basins of Dinkey Creek and 

North Fork of the Kings River, formed a mer de glace 1,500 

square miles in extent. Yet it was not an icecap, strictly 

speaking, for its surface was broadly concave rather than 

dome shaped. It consisted of a large number of confluent glaciers that had descended from the surrounding peaks and 

crests, filled the canyons, and overflowed on to the intermediate 

uplands.

The glacier system was essentially bilobate, as it comprised 

two great primary branches that descended Middle Fork and 

South Fork canyons. The branches united below the junction 

of the two forks, to form a very broad trunk glacier that overflowed the main San Joaquin Canyon and spread widely over 

the central part of the basin. The glacier ended in a rather 

blunt tongue, only a few miles long, which lay in that part 

of the main canyon separating Chiquito and Kaiser Ridges. 

The length of the San Joaquin glacier system, measured from 

the head of the South Fork branch to the terminus of the 

trunk glacier, was nearly 60 miles; the length measured along 

the Middle Fork branch was almost 45 miles.

Big Creek basin was occupied by a glacier system of its own. 

This system attained a length of about 20 miles and an areal 

extent of about 105 square miles.

During the Wisconsin stage of glaciation, in the San Joaquin 

Basin as elsewhere in the Sierra Nevada, the volume of ice 

was considerably smaller than in the earlier stage, and the 

ice-covered area was, therefore, much less extensive. The San 

Joaquin glacier system had, of course, the same general pattern as in the earlier stage, for it reoccupied most of the cirques 

and followed the same valleys and canyons, but it took the 

form of many discrete glaciers which became confluent only 

in part. Thus, large upland areas which were ice-covered in 

the earlier glaciation remain bare throughout the Wisconsin 

stage.

By far the greater part of the ice which formed in the San 

Joaquin Basin was again part of a bilobate system, and this 

pattern was the more pronounced because the ice was largely 

confined within the canyons or broad valleys. The trunk glacier in the main canyon, formed through union of the Middle 

Fork and South Fork glaciers, was only a short and feeble 

tongue. The maximum length of the San Joaquin glacier 

system, measured from the head of the South Fork to the 

terminus of the trunk glacier, was 47 miles; the length measured along the Middle Fork branch was 32 miles.

A number of glaciers, which in the El Portal stage were 

tributary to the San Joaquin glacier system, in the Wisconsin 

stage fell short of joining that system, and throughout their 

existence remained separate ice bodies or became confluent
INTRODUCTION

only with adjacent glaciers. This was the case with the 

Granite Creek glacier, the Big Creek glacier system, and the 

many relatively small glaciers on Chiquito Ridge, Kaiser 

Ridge, and other ridges.

INTRODUCTION

This report is based upon a reconnaissance of the 

upper basin of the San Joaquin River conducted hi 

1921, 1923, and 1927. By the upper basin (or what 

will hereafter, for convenience, be termed the San 

Joaquin Basin) is meant the mountain course of the 

San Joaquin River, situated in the central part of the 

west slope of the Sierra Nevada (fig. 1.) The San Joaquin Basin lies between the drainage basins of the Merced 

and the Fresno Rivers, on the northwest, and the 

drainage basin of the Kings River on the south. This 

report does not include the level plain at the west foot 

of the range which is traversed by the lower or valley 

course of the San Joaquin River the San Joaquin 

Valley, as it is generally called, or the southern part of 

the Great Valley of California; neither does it include 

the drainage basins within the Sierra Nevada of the 

other rivers which join the San Joaquin River on the 

plain.

Like each of the adjoining basins and those of the 

other master streams of the west slope of the Sierra 

Nevada, the San Joaquin Basin is a natural geomorphologic unit that can advantageously be treated by 

itself.

The reconnaissance with which this report deals 

was undertaken for a 2-fold purpose: first, to extend 

geomorphologic and glacial studies made in previous 

years in the Yosemite region southeastward, as a first 

step toward connecting that region with the as yet 

isolated area, 100 miles distant, in the basins of the 

Kern, Kaweah, and Kings Rivers, which had been 

investigated some years before by Lawson (1904,1906) 

and Knopf (1918) ; and second, to test the soundness 

of conclusions which the author had previously reached 

in the Yosemite region regarding the geomorphologic 

development and the glaciation of that region, and to 

determine their bearing on the history of the Sierra 

Nevada in general.

From preliminary map studies, it was expected 

that the San Joaquin Basin would prove to be a key 

area for the interpretation of the central and southern 

parts of the west slope of the Sierra Nevada, and this 

inference was fully confirmed.

The San Joaquin Basin, up to the time when these 

investigations were undertaken, had not been previously studied systematically. Very little was known 

of the geology of the area beyond the fact that its 

rocks are mostly granitic, except near the crestline

510207 60 2

of the range where metamorphic rocks prevail. Only 

one hasty reconnaissance had been made through it, 

namely, by Brewer's party of the California Geological 

Survey in 1864; but that initial exploration, as is 

evident from Whitney's report (Whitney, 1865) as 

well as from Brewer's original journal (Brewer, 1930) 

had yielded, besides a sketch map by Hoffman, only 

a few scanty geologic notes. To one who reads between the lines, it is plain that the party suffered 

many hardships not mentioned in its report, and that 

the overcoming of physical obstacles, and the ultimate 

safety of its members became problems of paramount 

importance to which scientific studies had to be largely 

sacrificed. Their reconnaissance is to be regarded 

primarily as of historic interest.

In the reconnaissance of 1921 the writer, therefore, 

found himself essentially in a virgin field. However, 

some conception of the outstanding landmarks of the 

basin had been gained previously from graphic articles 

published in the Sierra Club Bulletin and illustrated 

by excellent photographs; and by far the most valuable 

advance information about the region was obtained 

from the topographic maps that had been published 

about a decade previously by the U. S. Geological 

Survey.

Those parts of the San Joaquin Basin shown on the 

Mount Lyell, Mount Morrison, Kaiser, and Mount 

Goddard quadrangles were largely covered by the 

reconnaissance surveys. In addition, the foothill 

country shown on the Friant, Academy, and Dinuba 

quadrangles was given a cursory examination. Thus 

the San Joaquin River and its tributaries were traced 

from the peaks on the crest of the Sierra Nevada down 

to the mouth of the rock-cut canyon where the river 

begins its alluvial course over the sediments of the 

Great Valley of California.

The fieldwork consisted partly in analyzing the 

features of the landscape into elements belonging to 

successive surfaces of erosion, and partly in the systematic tracing and mapping of the moraines that 

mark the farthest extensions of the Pleistocene ice in 

each of the two well-defined and clearly distinct 

glacial stages. No means were found within the compass of the San Joaquin Basin for determining the 

age of any of the surfaces of erosion, owing to the 

absence of fossiliferous deposits. Nevertheless, the 

ages are not wholly indeterminate, for it was possible 

to correlate the erosion surfaces of this area with those 

previously recognized in the Table Mountain region of 

the Stanislaus basin (fig. 1), where fossils are present 

in the Tertiary stream deposits, and where the age of 

at least one erosion surface has been tentatively determined. No attempt was made to identify and map
GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

FIGURE 1. Index map showing location of the San Joaquin Basin.
INTRODUCTION

the different types of igneous rocks that constitute 

the great batholith of the Sierra Nevada and which 

form the prevailing country rock of the area, and 

no petrographic studies were undertaken in connection 

with the reconnaissance. Some attention was given, 

however, to the more important bodies of metamorphic 

rock, which are scattered here and there, and to the 

volcanic rocks, which consist of many small local flows 

of Tertiary and Quaternary age.

The author's investigations did not cover the San 

Joaquin Basin completely, and consisted mainly of 

a reconnaissance of its geomorphologic and glacial 

features. The foothill belt, in particular, received only 

minor attention, but as it was not practicable in the 

time available to cover all parts of the basin with 

equal thoroughness, and as the foothill belt presents 

a set of geomorphologic problems of its own, deserving 

special investigations, it seemed best to present the 

studies made in their present incomplete form.

ITINERARY OF EXPEDITIONS

In the summer of 1921 (July 8-October 1), the 

author, with a small party, made a preliminary reconnaissance across the entire breadth of the rugged San 

Joaquin Basin and back, traveling on horseback and 

equipped with a pack train. Starting from Yosemite 

Valley, he entered the San Joaquin Basin by the littlefrequented Fernandez Pass and thence descended into 

the valley of Granite Creek (pi. 1). Using Clover 

Meadow as a headquarters, the entire basin of Granite 

Creek and the so-called Jackass district to the south 

were explored. Crossing the North Fork of the San 

Joaquin Kiver, the party then traveled successively 

to "77" Corral, to Eeds Meadow and the Devils Postpile, and to Mammoth Pass; and finally up the Middle 

Fork of the San Joaquin River to its headwaters at 

Agnew Pass and Thousand Island Lake.

The party, doubling back, followed the Middle Fork 

southward to Fish Valley, ascended the upland toward 

Pincushion Peak, and cursorily examined the basin 

of Silver Creek. Then it descended into the valley 

of the South Fork of the San Joaquin Kiver and 

followed it up to the Lower Hot Springs, where a 

side trip was made into Vermilion Valley 2 and up 

the canyon of Mono Creek. Resuming its journey 

up the South Fork, the party traveled to Blaiiey 

Meadows and examined the area around Selclen Pass, 

then continued up Evolution Valley, and using this 

as a base, explored Evolution Basin as far as the 

Muir Pass, as well as the rugged country around 

Mount Darwin, the Glacier Divide, and Mount McGee.

2 This valley is now occupied by Lake Thomas A. Ertison.

The return was made down the South Fork to Blaney 

Meadows, over the Hot Springs Pass to Long Meadow, 

where the country at the head of Big Creek was 

covered; then on to Hunting-ton Lake, northward over 

Kaiser Ridge, and down Kaiser Creek to Daulton 

Ranger Station. Scarcity of grass due to prolonged 

drought made it impracticable to keep the pack train 

in this area and compelled the party to hasten across 

the San Joaquin River to Placer Ranger Station. 

After a brief halt there, to examine the more accessible parts of the Chiquito Creek basin, the march continued in a northwesterly direction by Beasore and 

Mugler Meadows to the Chiquito Pass, where the 

Merced Basin and the Yosemite National Park were 

reentered on October 1.

In the spring, and early summer (July 3-30) of 

1923, the lower part of the San Joaquin Basin, which 

is traversed by several roads, was visited by automobile. 

From Fresiio, a reconnaissance was made through the 

foothills and up the grade from Tollhouse to Shaver 

Lake, Big Creek, and Huntington Lake. The return 

trip was made through the lower San Joaquin Canyon, 

which that year for the first time had been made 

accessible by the opening of automobile roads built 

by the Southern California Edison Company to connect its chain of power stations. During the remainder 

of the field season a second pack train expedition was 

made from the Yosemite Valley through the roadless 

western and central parts of the San Joaquin Basin, 

examination of which had to be abandoned in 1921 

owing to lack of pasturage for the pack train. On 

this second trip, conditions were more favorable, and 

time was spent in the large tract stretching from 

Kaiser Ridge northward to the junction of the South 

Fork and Middle Fork of the San Joaquin River.

In 1927 (June 27-September 18) opportunity was 

had for a supplementary and somewhat more detailed 

examination of a limited area immediately surrounding 

Huntington Lake and extending southward to the 

valley of Dinkey Creek. This additional work seemed 

particularly desirable in view of the great hydroelectric 

developments centering about Huntington Lake, and 

the rapid transformation of the surrounding region 

into one of the major summer tourist centers of the 

Sierra Nevada. (See later paragraph on "Economic 

and Social Use," page 12.)

INVESTIGATIONS SUBSEQUENT TO FIELDWORK

Since this reconnaissance, a number of noteworthy 

studies have contributed to the geologic knowledge 

of the central and south-central parts of the Sierra 

Nevada. Those of special significance to this report 

may be briefly mentioned. Hans Cloos and Ernst
6 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

Cloos (Ernst Cloos, 1933) have applied their technique 

of structure analysis to various parts of the Sierra 

batholith. Mayo (1930, 1934, 1935, 1937, and 1941; 

Locke, Billingsley, and Mayo, 1940) has extended 

these studies throughout the central and southern 

Sierra Nevada, including the San Joaquin Basin, by 

his regional investigations of the structures of the 

intrusive rocks and their relations to the metamorphic 

rocks. Erwin (1934, 1937) has made an intensive 

study of the metamorphic rocks and associated mineral 

deposits in the region at the head of the Middle Fork 

of the San Joaquin Eiver. Blackwelder (1932) has 

studied the evidences of successive glaciations on the 

eastern flank of the Sierra Nevada. Macdonald (1941) 

has investigated the metamorphic and igneous rocks 

in the foothills belt of the western Sierra Nevada 

between the Kings and the San Joaquin Rivers. Webb 

(1946) has presented new evidence for the events in 

the evolution of the Middle Kern Basin, and has revised some of Lawson's earlier interpretations. The 

author (Matthes, 1930a, 1933a, 1933b, 1937, 1950b) has 

followed up geomorphologic studies in the Yosemite, 

Tuolumne, and San Joaquin Basins by related investigations in the basins of the west-slope rivers in 

the southern part of the Sierra Nevada, and by more 

intensive investigations at selected points along the 

eastern flank of the range, from the vicinity of Mono 

Lake southward to the Alabama Hills (fig. 1). As 

this report is being completed, Birman (1954) has 

published, in abstract, the results of a recent, detailed 

study of the glacial record along the South Fork of 

the San Joaquin Eiver and its tributary, Mono Creek.

ACKNOWLEDGMENTS

During the summer of 1921, the writer was ably 

assisted in the field by Mr. Francis Cameron. The 

writer also wishes to acknowledge his indebtedness 

to officials of the Southern California Edison Company 

and the Forest Service of the U.S. Department of 

Agriculture for their courtesies in connection with 

this reconnaissance. Certain data in this report have 

been taken, with the permission of the Vanguard Press, 

from the chapter entitled "A Geologist's View" which 

the writer contributed to "The Sierra Nevada: the 

Range of Light" (Matthes, 1947). Data have also 

been taken, with the permission of the University of 

California Press, from the writer's volume, "The Incomparable Valley: A Geologic Interpretation of the 

Yosemite" (Matthes, 1950b). Grateful acknowledgment is made to Mr. Charles S. Denny, whose painstaking and critical review of the manuscript led to 

many constructive suggestions which were adopted.

GEOGRAPHIC SKETCH 

LOCATION AND EXTENT OF AREA

The San Joaquin Basin is one of the largest of the 

many basins on the west slope of the Sierra Nevada, 

whose rivers drain into the Great Valley of California 

(fig. 1). It lies immediately southeast of the scenic 

central part of the range, which is mostly in Yosemite 

National Park. In its outlines, the basin is roughly 

comparable to a wedge-shaped leaf (fig. 2). Broadest 

at the crest of the range, it narrows southwestward 

to a point at the foothills.

The most northerly point of the basin, near Agnew 

Pass Q:)!. 1), is at latitude 37°44'; its southernmost point, 

in the foothills below Friant, is at latitude 36°55'. The 

basin extends from longitude 118° 39' at Mount Wallace 

westward to longitude 119 °47' in the foothills west of 

the San Joaquin River.

The northwestern part of the basin lies in Madera 

County, the southeastern part in Fresno County. The 

San Joaquin River is the boundary between the two 

counties from the foothills to a point near the center 

of the basin; from this point the boundary extends 

northeastward in a straight line to the crest of the 

range. The entire basin is included in the Sierra 

National Forest save its southern foothills and the 

scenic area at the southeast corner of the basin which 

includes Evolution Valley, Evolution Basin, and Goddard Canyon, and their confining crests; these are 

parts of the Kings Canyon National Park.

On the northwest, the San Joaquin Basin adjoins 

the relatively small drainage basin of the Fresno River, 

which reaches only about half-way up the west slope 

of the Sierra Nevada. Above this, it adjoins the 

larger drainage basin of the Merced River, which ex-

~ o ' _

tends all the way to the crest of the range. The San 

Joaquin Basin is walled off from the Merced Basin 

by a chain of lofty crests and peaks.

On the south the San Joaquin Basin borders the 

drainage basin of the Kings River, which is slightly 

smaller. The two basins are separated by a long line 

of serrate j>eaks which, toward the lower levels, give 

way to irregular, plateaulike uplands.

On the northeast that is, at its extreme head, which 

is throughout determined by the main drainage divide 

on the crestline of the Sierra Nevada the San Joaquin 

Basin abuts upon the east front of the range, which 

drains into Owens Valley and the lesser basins at its 

head, except for a short stretch at the extreme north 

end, which drains into the basin of Mono Lake.

From the crestline to the foothills the basin measures 65 miles in length; it is 54 miles wide, measured 

along the crestline of the range; and its area comprises
GEOGRAPHICAL SKETCH
GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

1,760 square miles. The outlines of the tract are fairly 

regular, the salients and indentations in its sides being 

for the most part small and roughly compensating. 

The only significant departure from the wedge shape, 

mentioned previously, is a projection 10 miles in length 

at the southeast corner.

DRAINAGE AND TOPOGRAPHY

The outlines of the San Joaquin Basin have been 

compared to those of a wedge-shaped leaf, and similarly the drainage lines may be likened in a general 

way to the venation of that leaf. The San Joaquin 

River, in its upper course known as the Middle Fork, 

forms the crooked midrib, running southwesterly. The 

North Fork extends up into the principal left lobe, 

at the north; the South Fork into the much larger 

right lobe, at the southeast; and other smaller tributaries each into a minor lobe.

Thus the San Joaquin River, like nearly all of the 

great master streams of the Sierra Nevada, pursues 

mainly a southwesterly course down the west slope and 

transverse to the crestline of the range. Most of its 

tributaries, on the other hand, pursue northwesterly 

or southeasterly courses, approximately at right angles 

to it and unaffected by the general southwestward slope 

of the range. The preponderance of these longitudinal 

elements in the drainage net will be apparent from 

a glance at the drainage map, figure 2.

The longest and most important of the longitudinal 

streams is the South Fork of the San Joaquin, which 

flows northwestward throughout its course save in the 

'3-mile stretch immediately above its junction with the 

Middle Fork, where it turns southwestward. The 

South Fork is 52 miles long 17 miles longer than 

the Middle Fork; for that reason and because of its 

greater volume, it might well be regarded as the true 

upper course of the master stream. Several of its 

tributaries have northwestward-trending courses, in 

whole or in part. Such are Evolution Creek, Piute 

Creek, and Bear Creek the two last named flowing 

northwestward in their upper courses and then making 

a right-angle turn to the southwest in their lower 

courses. Other tributaries of the San Joaquin that 

flow mainly in northwesterly directions are Kaiser 

Creek, Big Creek and its branch Tamarack Creek, 

Stevenson Creek, and Big Sandy Creek. Tributary 

to the Middle Fork is Fish Creek and its branch, 

Silver Creek.

Among the southeastward flowing streams are to be 

counted the upper course of the Middle Fork itself, 

from the vicinity of Agnew Pass to Pumice Flat; 

Minaret Creek, King Creek, the North Fork of the

San Joaquin (which heads on Rogers Peak) and 

several of its tributaries; Granite Creek and its forks; 

Chiquito Creek and several of its tributaries; Rock 

Creek; and Willow Creek.

The above list includes all of the major affluents 

of the San Joaquin, with the exception of Jackass 

Creek and Fine Gold Creek, which flow mostly in 

southerly directions; but even these streams have long 

southeastward-trending stretches and branches, and 

taken as a whole, trend east of south rather than west 

of south.

The San Joaquin Basin reaches all the way from the 

foothills to the crestline, and has the full hypsometric 

range of the Sierra Nevada, which at this latitude is 

considerably more than 13,000 feet. The two extremes 

in altitude are the bed of the San Joaquin River at 

the foothills, 5 miles below Friant, which is only 285 

feet above sea level, and the summit of Mount 

Humphreys, on the crestline, which attains 13,972 feet. 

A straight line drawn between these two points, which 

are 63 miles apart, slopes at an angle of 2°21', or at a 

mean rate of 217 feet to the mile (equivalent, approximately, to a 4 percent grade). This inclination 

is representative in a general way of the central part 

of the Sierra Nevada, and is intermediate between 

the slope of the northern part, which is only 1°24', 

or 128 feet to the mile (2.4 percent), and that of the 

culminating part, in the latitude of Sequoia National 

Park, which, measured from the foothills to the Great 

Western Divide, is 4° 30', or 416 feet to the mile 

(7.9 percent).

Most of the mountain crests are on the upper slope 

of the San Joaquin Basin that is, in the part commonly termed the "High Sierra." The middle slope 

is by contrast signally devoid of serrate crests, being 

predominantly a region of plateaulike uplands that 

have a general southwestward slant and bear scattered 

hills and knobs of moderate height. Less impressive 

scenically, but equally interesting to the student of 

lanclforms, are these undulating, billowy uplands, 

which aggregate about a hundred square miles in area. 

They are sharply trenched by the San Joaquin River 

and its main branches, which have cut impressive 

canyons more than 2,000 feet deep; but the upland 

surfaces themselves are drained by tributary streams 

which follow, mostly, broad shallow valleys. From 

the mouths of these valleys, the tributaries generally 

descend abruptly into the deep canyons, by cascades 

and even waterfalls. So characteristic of the region 

is this situation that the San Joaquin Basin might 

be termed a "land of hanging valleys." Though it 

does not possess an array of spectacular waterfalls 

such as distinguish the Yosemite region, it does have
GEOGRAPHICAL SKETCH 9

a wealth of beautiful cascades. In some places, as 

south and southeast of Shaver, the upland persists 

to within a few miles of the foothills and there breaks 

off in steep bluffs of considerable height. The foothill 

belt, again, contains short northwestward-trending 

ridges and detached mountains 1,000 to 1,500 feet high.

The mean inclination for the entire San Joaquin 

Basin is, however, considerably less than 2°21', for the 

crestliiie itself varies more than 4,700 feet in altitude. 

At one point, Minaret Pass (not marked on Mount 

Lyell quadrangle, but situated directly east of Pumice 

Flat, in the upper Middle Fork Canyon), the crest 

descends to an altitude of 9,200 feet. A line drawn 

from this lowest point on the main divide to the 

western foot of the range, slopes at an angle of only 

1°35', or at a rate of 147 feet to the mile (2.8 percent). 

The mean inclination for the entire basin is probably 

not far from 1°54', or 174 feet to the mile (3.3 percent).

These figures, however, take no account of the actual 

configuration of the San Joaquin Basin, which is 

diversified by boldly sculptured, serrate mountain 

crests, plateaulike uplands, and deep valleys and canyons.

The mountain crests include a few that trend southwestward, down the slope of the Sierra Nevada, but 

most of them, including those that are especially prominent in the configuration of the basin, trend northwestward, parallel to the axis of the range and at 

right angles to the course of the San Joaquin Eiver, 

thus interrupting and accidenting the general southwestward slope. These crests, ranging from 2,000 to 

more than 2,500 feet in height, rise high enough above 

the adjoining uplands and valleys to be called mountain ranges. The persistent trend of these crests has 

affected the arrangement of the tributary streams, 

which, as previously emphasized, show a remarkable 

tendency to flow in southeasterly or northwesterly 

directions, at right angles to the general direction of 

their master stream.

From the foregoing description it is evident that the 

San Joaquin Basin on the whole does not in any 

sense slope gradually and continuously down to the 

level of the Great Valley of California. It differs 

markedly in that respect from the more gently sloping 

northern parts of the Sierra Nevada which afford 

grades for railroads and highways. The configuration 

of the San Joaquin Basin is such that a person who 

would travel in a straight line from the main divide 

down to the foothills, instead of having a fairly continuous descent, would find himself obliged to make 

repeated arduous climbs and steep descents. The canyon of the San Joaquin is too rugged to serve as a 

convenient avenue for travel, and as a consequence, the

main routes are on the uplands on either side of the 

canyon and over the transverse ridges. Some conception of the irregularities in the slope of the San 

Joaquin Basin may be gained from the profile in figure 

3 which is plotted without vertical exaggeration.

Among the topographic anomalies in the San 

Joaquin Basin one is especially noteworthy. This is 

the sag in the crestliiie of the range at Minaret Pass, 

a peculiar feature that differentiates the San Joaquin 

Basin from all other parts of the Sierra Nevada, except 

the basin of the Feather Eiver near the northern end 

of the range. The pass is more than a mere notch 

in the otherwise remarkably continuous crest of the 

mountain block. It is a 5-mile stretch of low altitude 

that includes also Mammoth Pass (9,300 feet) at its 

southern end. Mammoth Mountain is an ancient volcano located in the middle part of the sag. The 

dwindling of the main drainage divide here is accentuated, moreover, by two other unusual circumstances : by the breaking clown of the generally precipitous eastern escarpment of the Sierra Nevada in this 

section to a slope of moderate declivity only about 

1,000 feet in height; and by the presence, 6 miles to 

the west, of one of the most impressive of the longitudinal crests, the Eitter Eange, whose lofty summits, 

more than 12,000 and 13,000 feet in altitude, far overshadow the low and subdued main divide (fig. 4).

CLIMATIC CONDITIONS 3

The San Joaquin Basin, being centrally situated in 

the Sierra Nevada, shares in the climatic conditions 

and life zones that are typical for the west slope of 

the range.

Like every other mountain range of great height 

and extent, the Sierra Nevada is itself a "climate 

maker"; that is, in large measure it is the author of 

its own weather conditions and controls those of the 

regions to the leeward. Lying parallel to the Pacific 

coast, it forms a barrier over which the vapor-laden 

winds that blow in from the ocean must rise. As they 

are forced up to high levels, they are chilled and discharge their condensed water vapor. This heavy precipitation on the Sierra Nevada explains the general 

barrenness of the Great Basin. The air currents are 

fairly wrung dry as they pass over the range.

About 18 percent of the total annual precipitation 

falls in autumn, about 53 percent in winter (mostly 

snow), 26 percent in spring, and less than 3 percent 

in summer.

3 This section has been based on the following sources : Erwiu, 1934, 

p. IT-18; Matthes, 1930a, p. 10-11; Matthes, 1933a, p. 27-28; Russell, 

1938. p. 73-84; Russell, 1947, p. 323-340.
10 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

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Thus the summers are remarkably dry. Rainless 

periods of 2 or 3 months are the rule, though occasional thunderstorms may occur, especially in the 

High Sierra. Camping without tents is a common 

practice, and the higher parts of the range have such 

an enjoyable and healthful summer climate that they 

have become a mecca for vacation seekers.

Torrential rains are uncommon and floods on Sierra 

streams are generally the result of unusually rapid 

melting of snow, rather than of heavy rainfall. The 

Sierra is almost free of violent storms. Large windfalls of trees, such as result from gale-velocities, are 

comparatively rare.

The extreme heavy snowfall of the Sierra Nevada 

results from the coincidence of maximum precipitation with the season of lowest temperature a coincidence that also explains the persistence of a deep 

snow cover until late spring or even later. Winter 

snows exceed those of any other part of the United 

States, except for the Olympic Mountains and the 

northern Cascade Range. According to United States 

Weather Bureau records, the annual snowfall at stations 

on the Southern Pacific Railroad, at altitudes between 

6,000 and 7,000 feet on the west slope, aggregates 30 

to 40 feet in depth. Records of more than 60 feet 

are fairly common above a 6,000-foot altitude. Snowfalls of 5 feet within 24 hours, and over 32 feet within 

a single month, have been reported. At Huntington 

Lake the depth of the snow cover in February and 

March, in some years, is nearly 10 feet, and from other 

localities depths almost twice as great have been reported.

The Sierra Nevada is not, of course, equally favored 

with moisture in all its parts. The annual precipitation increases with elevation, on the western slope, at 

rates varying from 0.75 to 1.33 inches for each 100 

feet of vertical ascent, up to altitudes of 5,000 to 6,500 

feet, above which the rate slightly decreases. Thus 

the bulk of rain and snow falls on the middle part 

of the west slope, and the foothills and lower slope 

partake in large measure of the semiarid conditions 

that prevail in the Great Valley. The higher peaks 

and crests above the forest zones are also relatively 

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slope, but that is due primarily to the lingering cold. 

The east front of the range also is arid compared with 

the west slope.

From altitudes of 11,000 feet upward, the precipitation, even in summer, consists largely of snow or hail, 

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exaggeration, emphasizes the anomalous lowness of the main drainage divide in this section as compared with the greatly superior altitude of 
12 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

small plants, many of which bear brightly colored 

flowers.

ECONOMIC AND SOCIAL USE

All of the San Joaquin Basin, except the southwestern foothill section and the Evolution Valley 

region, is included in the Sierra National Forest. The 

basin is of great importance for its water resources 

and as a recreational, lumbering, and grazing area. 

Most of the information in this section was furnished 

by the Office of the Supervisor, Sierra National Forest, 

Northfork, California. Maps of the Sierra National 

Forest, available from the Forest Service on scales 

of both one-quarter and one-half inch to the mile, show 

most of the features mentioned.

Within recent decades, mainly since this reconnaissance was made, a remarkable development of human 

activities, both economic and social, has taken place 

in the basin. Hydroelectric power is now being generated on a large scale. The hydroelectric development 

of the Southern California Edison Co., which utilizes 

the Shaver Lake, Huntington Lake, and Lake Florence 

reservoirs (fig. 2) is the largest project of this company, and is reputed to represent a total outlay exceeding the cost of the Panama Canal. Crane Valley Lake 

and Kerckhoff Lake serve a project of the Pacific 

Gas and Electric Co. Work in progress, leading to 

the construction of new plants, is also increasing the 

outlay of existing plants by adding to present storage 

facilities.

The entire flow of the San Joaquin River is being 

utilized for downstream irrigation in the highly productive San Joaquin Valley. Average annual runoff 

is close to 11/2 million acre-feet, all covered by downstream water rights. At Friant (see Friant quadrangle), just outside the Sierra National Forest, is Millerton Lake (fig. 2), which is formed by Friant Dam, 

a part of the Central Valley irrigation project of the 

U.S. Department of the Interior.

The building of roads in connection with these 

projects has opened to the public a large area of 

rugged, mostly forested mountain country at lower and 

middle altitudes, that was previously inaccessible except by steep rough trails. There has followed a 

great influx of vacationists whose numbers have grown 

as opportunities for recreation have increased. During 

the 1949 season there were about 990,000 recreational 

visitors to that part of the Sierra National Forest 

within the drainage of the San Joaquin Eiver.

The San Joaquin Basin, although on the whole 

less notable for its mountain scenery than the Yosemite 

region to the north, and less deeply gashed by canyons 

than the Kings River Basin to the south, nevertheless

includes some of the finest alpine scenery in the Sierra 

Nevada. The extreme southeastern corner of the basin, 

embracing Evolution Valley and Basin, and Goddard 

Canyon, is included in Kings Canyon National Park, 

established by act of Congress on May 4, 1940.

The Forest Service, in order to preserve the wilderness state of typical mountain and forest areas, has 

set apart a number of tracts of national forest land 

that will be left in their natural condition, without 

roads and other permanent recreational developments. 

Two such areas have been established in the Sierra 

National Forest, and both include extensive parts of 

the San Joaquin Basin. The Dana-Minarets Wild 

area, of 87,140 acres, lies immediately north and northwest of the Devils Postpile National Monument. The 

High Sierra Wilderness Area, of 393,945 acres, extends 

along the crest of the range from the Mammoth Lakes 

southward to the Kings Canyon National Park. 

Through these wilderness areas passes the famous John 

Muir Trail in its course from Tuolumne Meadows, 

in Yosemite National Park, to Mount Whitney, in 

Sequoia National Park (Starr, 1953). Mountaineering 

enthusiasts who visit the upper San Joaquin Basin 

over this trail or its approaches, afoot with knapsack, 

or on horseback with packtrains, make excursions from 

their basecamps into the surrounding areas, and climb 

peaks of the Evolution group, the Ritter Range, and 

other alpine sections of the High Sierra (Voge, 1954).

An area of 39,000 acres which almost surrounds 

Huntington Lake and lies mostly to the north of that 

lake, was designated the Huntington Lake State Game 

Refuge in 1931. In this area, set aside for the protection and propagation of wild life, firearms may not 

be discharged for any reason.

The Devils Postpile National Monument, justly celebrated for its remarkable development of columnar 

structure in basalt (Matthes, 1930b), brings visitors 

into the otherwise little frequented country in the 

Middle Fork Canyon of the San Joaquin River. This 

monument, administered by the Superintendent of 

Yosemite National Park, lies at an elevation of 7,000 

to 8,000 feet, is about 2% miles long and % niile wide, 

and has an area of 798^ acres.

Mineralization has occurred in the metamorphic 

rocks of both the foothills zone (Macdonald, 1941, p. 

267-270) and the Minaret mining district, in the Ritter 

Range region at the north end of the San Joaquin 

Basin (Erwin, 1934, p. 10-11, 61-78), but there has 

been virtually no mineral production of significance. 

The Minaret district, in particular, has been extensively prospected, and ore bodies have been found containing iron, lead, zinc, copper, and silver, as well as 

minor amounts of molybdenum, tungsten, and bismuth.
ROCKS 13

On the upper slope of Iron Mountain, in this district, 

is a body of magnetite that has long attracted the 

attention of miners and that possibly would be profitable to exploit if it were more accessible to roads and 

markets.

The notable economic and social developments, together with the increasingly great popular interest in 

the San Joaquin Basin, give added interest to the 

geomorphological features which are described and 

interpreted in this report.

ROCKS

Before taking up the detailed consideration of the 

landforms in the San Joaquin Basin, it will be desirable to consider first the nature of the rock materials 

from which these forms were carved. For this report, 

the subject may be treated briefly, and mainly from 

the geomorphological point of view, with emphasis 

on facts related to the development of landforms. 

Only incidental reference is made, therefore, to structure and to petrologic details.

The rocks of the San Joaquin Basin belong mainly 

to the three general classes that occur throughout the 

greater part of the Sierra Nevada (fig. 5) ; namely, the 

granitic rocks that make up the vast compound batholith of Late Jurassic or Early Cretaceous age; the 

metamorphosed sedimentary and volcanic rocks of 

Paleozoic and Mesozoic age into which the granitic 

rocks of the batholith were intruded; and the volcanic 

rocks of Tertiary and Quaternary age that lie unconf ormably upon these older rocks as a discontinuous, 

surficial veneer.

Further mention should be made of the glacial deposits of Pleistocene age in the higher parts of the 

basin (described in the chapter on glaciation); the 

alluvial deposits of Quaternary age which underlie 

many upland meadows and form narrow flood plains 

in the lower stream channels, notably that of the San 

Joaquin River, below Friant; and, finally, the sediments of Tertiary age, terrace gravels of Quaternary 

age, and alluvial fans of Quaternary age at the west 

border of the range, where the crystalline complex 

of rocks of Paleozoic and Mesozoic age constituting 

the Sierra block passes from view beneath the floor 

of the Great Valley.4

GEANITIC EOCKS

Of the three main classes of rocks in the region, the 

granitic rocks are by far the most abundant. They 

occupy the greater part of the basin, their outcrops

4 This border area is marginal to the region with which the present 

report primarily deals, and has been studied in detail, chiefly from the 

stratlgraphic and petrographic standpoints, by Gordon A. Macdonald 

(1941).

extending, with only a few important interruptions, 

from the crestline of the range to the western foothills. 

Even the outlying island hills that project above the 

sediments of the Great Valley of California, in front of 

the range, are composed largely of granitic rocks.

The term "granitic," as used in this report, includes 

a considerable variety of undifferentiated plutonic 

rocks, mainly of siliceous types. Besides granite, 

granite porphyry, and micropegmatitic granite, they 

include chiefly quartz monzonite, quartz diorite, 

granodiorite, and gabbro. In this reconnaissance the 

writer made no attempt systematically to distinguish 

and map these rocks, but this has since been done by 

Calkins (1930, p. 120-129) for the nearby Yosemite 

region and by other geologists for parts of the San 

Joaquin Basin. The studies by these geologists serve 

to shed light on the granitic rocks of the basin as a 

whole.

On his map of the foothills zone between the San 

Joaquin and Kings Rivers, Macdonald (1941, p. 217, 

251-257, 271-273) distinguishes an earlier group of 

hornblende gabbros and hornblende diorites from a 

later group of intrusive rocks which includes hornblende biotite quartz diorite, pyroxene quartz diorite, 

and muscovite granite. Of these rocks, the quartz 

diorite occupies by far the greatest area. It is described as being quite uniform in composition throughout the area mapped but variable in appearance because 

of differences in grain size, structure, and texture.

In the southeastern part of the Mount Lyell quadrangle, Erwin (1934, p. 7-78; 1937, p. 391-413) found 

that the composite Sierra Nevada batholith includes 

intrusive igneous bodies of five types: andesine diabase, 

diorite porphyry, diorite, quartz monzonite-diorite, and 

micropegmatitic granite. These rocks, intruded in an 

order of increasing silica content, are thought to have 

resulted from one general period of igneous intrusion. 

The quartz monzonite-diorite composes the main mass 

of the batholith.

Mayo (1937, map p. 172; 1941, map facing p. 1000), 

in making a northeasterly geologic section through 

the San Joaquin Basin, found that the granodioritegranite series extends uninterruptedly from the vicinity 

of Black Mountain (southwest corner of Kaiser quadrangle) almost to the crest of the range, a distance of 

about 45 miles. He has differentiated on his map a 

long narrow intrusion of porphyritic quartz monzonite 

which extends southeastward from the south end of 

the Hitter Range. This intrusion, distinguished by 

large phenocrysts of potassium feldspar, he designated 

as the Cathedral Peak granite, using the name previously given by Calkins (1930, p. 126-127) to the rock 

of this type in the Yosemite region.
14 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

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ROCKS 15

JOINTING AND EXFOLIATION

In the San Joaquin Basin, as in the Yosemite region 

(Matthes, 1930a, p. 39), the granitic rocks are sparsely 

jointed, in many places the intervals between fractures 

measuring tens, hundreds, or even thousands of feet. 

However, in some places the granitic rocks are closely 

jointed (that is, have joints spaced one to several feet 

apart). As in the case of the Yosemite region, the 

character of the jointing has played a dominant role 

in governing the manner and rate of weathering processes, and of erosion by streams and glaciers, as well 

as in determining the character of the resultant landforms. In fact, the concepts of these processes and the 

analyses of the distinctive forms produced, as set forth 

in the author's report on the Yosemite Valley, were 

based on broad regional studies made in many parts 

of the Sierra Nevada, including the San Joaquin 

Basin. These concepts and analyses need not be restated here, but the illustrations in the present report 

include a number of views depicting representative 

landforms developed in the granitic rocks of the San 

Joaquin Basin.

In the Geographical Sketch, reference was made 

to the plateaulike uplands (p. 8) which are a distinctive feature of the central part of the San Joaquin 

Basin, and also to the broad shallow valleys which 

hang with respect to the San Joaquin Canyon and its 

principal branches. The exceptional preservation of 

the uplands and their hanging valleys is accounted 

for by the durability of the massive granite which 

underlies them. Some geologists would account for the 

relatively abrupt drop from the plateau to the foothills, 

south and southwest of Shaver Lake, by faulting, but 

no clear evidence of faults was discovered, and the 

same topographic effect could readily have been produced by differential erosion in well-fractured bodies 

of granite in juxtaposition to massive granite. The 

edge of the plateau south of Shaver Lake, which is 

scalloped by the heads of branches of Blue Canyon 

at the head of Big Creek, can hardly be delimited by 

a fault or zone of faults, but appears to indicate 

approximately the boundary between the massive rocks 

to the north and the fractured rocks to the south, in 

which a normal erosion topography, with dendritic 

drainage pattern and forking spurs and spurlets, has 

been developed.

The large-scale exfoliation of massive granitic rocks, 

so remarkably illustrated in the Sierra Nevada, is 

evident in many places in the San Joaquin Basin. The 

cause of this exfoliation is still obscure. Some geologists consider the most probable primary cause to be 

the liberation of expansive stresses within the granite, 

as the result of the progressive removal of superincumbent loads of rock by erosion; probably auxiliary 

causes are diurnal insolation and secular warming 

(Gilbert, 1905a, 1905b; Matthes, 1930a, p. 114-115; 

Matthes, 1937b). Exfoliation along plane or convex 

surfaces is illustrated at various places on the sides 

of the San Joaquin gorge, for example below the mouth 

of Big Creek, and on benches around the head of 

Evolution Creek, and elsewhere. Domes, the striking 

rounded forms evolved from giant monoliths by longcontinued exfoliation, are neither numerous nor, generally, as spectacular in this basin as in the Merced 

Basin, but nevertheless examples are found.

Balloon Dome (altitude 6,900 feet) is the outstanding 

dome in the region (figs. 6, 15). It is situated between 

the Middle and South Forks of the San Joaquin Eiver, 

immediately above the junction of the two streams. This 

dome is referred to in J. D. Whitney's report (1865, 

p. 401) as "a most remarkable dome, more perfect in 

its form than any before seen in the state," and it is 

described as having "exactly the appearance of the 

upper part of a sphere; or, as Professor Brewer says, 

'of the top of a gigantic balloon struggling to get up 

through the rocks.' " As a matter of fact, it is not 

as regularly shaped as many of the domes of the 

Yosemite region, but because of its strange form, 

unique situation, and bare figure all the more conspicuous because the surrounding uplands are forested it 

is an imposing landmark.

Two miles to the northwest of Balloon Dome is 

Squaw Dome (altitude 7,806 feet), also a conspicuous 

topographic feature (fig. 7) ; and in the vicinity are 

Cattle Mountain (fig. 6), the Balls, and several other 

relatively small subdued domes. Near Cascada station, 

providing a background for the Big Creek Falls, is 

Kerckhoff Dome (fig. 19, not shown on topographic 

map) ; and on the north boundary of Kings Canyon 

National Park, occupying a position within the fork 

formed by Piute Canyon and the valley of the South 

Fork of the San Joaquin Eiver, a situation very similar 

to that of Balloon Dome, is Pavilion Dome (altitude 

11,721 feet). On Chiquito Ridge, exfoliation is prevalent but not regular and continuous, owing to steepness 

of the slopes and the presence of interfering master 

joints. Peaks and spurs of the ridge are imperfect 

domes, and on the exfoliation surfaces, rainwash flutings are common (fig. 8).

MODES OF WEATHERING

Exfoliation is not a universal phenomenon of the 

massive granitic rocks. In places, for example on Bald 

Mountain, east-southeast of Shaver Lake, one may see 

immense exposures of massive granitic rock that are 

not exfoliating in the manner so characteristic of the
16 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

FIGURE 6. View northwestward across the canyon of the South Fork 

of the San Joaquin River, toward Squaw Dome (left background), 

Balloon Dome (center of picture), and part of Cattle Mountain (in 

background at extreme right). The canyon of the Middle Fork 

extends across the view immediately back of Balloon Dome.

domes of the Yosemite region. The rock on Bald 

Mountain disintegrates into granules, which are washed 

away by rainwater and accumulate farther down the 

slope in large quantities. Exfoliation partings appear 

here and there, but are not conspicuous.

A striking feature in fresh road cuts on the steep 

grade above Tollhouse and on other roads leading to 

Shaver Lake is the massive granite, breaking down by 

mechanical processes, and without significant chemical 

decomposition. On the middle and upper parts of the 

San Joaquin Basin, accumulations of loose granular 

sand resulting from disintegration of the granitic rocks 

is one of the most widespread phenomena. The sand 

covers the lower slopes of bare rocky hills and ridges, 

and deeply cloaks the interfluves on the uplands. On 

the moraines of the later glaciation, the sand accumuFIGURE 7. 'Squaw Dome, situated about 3 miles north of the junction 

of the Middle and South Forks of the San Joaquin River. The view 

is from the east. Exfoliating granite forms the bare slopes of Squaw 

Dome and a lesser dome to the right.

lates in the swales and on the upslope sides, so that 

the crests become flattened. The moraines of the earlier 

glaciation are in many places so mantled with sand 

derived from the disintegration of the glacial 

boulders that the materials of the moraine itself are 

exposed only here and there, generally where the uprooting of trees has revealed boulders and cobbles. 

As was explained in the author's report on the 

Yosemite Valley (1930a, p. 107-108), the disintegration 

of the granitic rock in these situations appears to be 

in the main a phenomenon of mechanical weathering, 

due largely to the disruptive effect of solar heat. Frost 

presumably plays a part in this disruption, but if so, 

only a very subordinate part, for typical frost cracks 

are absent in the rock masses wherein it occurs. The 

loose grains show scarcely any effects of chemical decomposition, even when examined under the microFIGURE s. Imperfect development of domes in sparsely jointed granite 

on Shuteye Peak (altitude 8,358 feet), principal summit of Chiquito 

Ridge. The flutings are produced by rainwater, guided, in part, by 

minor joints.

scope. The crystals of feldspar are but slightly cloudy 

at the edges, and the flakes of biotite and rods of hornblende as a rule show no alteration. However, this 

crumbling of the granite into undecomposed grains 

takes place only on the domes, cliffs, and other conspicuously bare rock masses that are subjected to intense insolation. In the densely forested areas on the 

uplands, where the heat of the sun is partly excluded 

by the foliage of the trees, and where the granitic rocks 

are covered by a layer of moisture-conserving, acidproducing humus, the chemical processes reduce the 

granite in much the same way as in a humid region. 

The massive granitic rocks also disintegrate by flaking off in thin scales, the thickness of these as a rule 

being only % mcn but ranging from % inch to 1 inch. 

The scales vary in size but commonly break off in 

patches a few inches in diameter. Evidences of decomposition under the flakes, promoted by moisture and
ROCKS 17

by the presence of green algae and lichens, are found 

in some places.

METAMORPHIC ROCKS

The granitic rocks are interrupted at many places 

by small to moderately large masses of metamorphic 

rocks of Paleozoic and Mesozoic age. The largest of 

these masses are found in the foothills region, in the 

Mount Hitter region at the northern end of the basin, 

and in the Goddard Canyon region in the southeastern part of the basin.

The metamorphic rocks in the foothills region are 

a part of the broad belt of such rocks extending along 

the lower west slope of the Sierra Nevada. The belt is 

traversed, farther north, by the gold-bearing quartz 

veins of the Mother Lode system (Jenkins, 1938). Remarkably continuous as far southeast as the Merced 

Basin, this belt narrows notably near Mariposa, but 

tongues continue across the Chowchilla Basin and into 

the Fresno Basin (fig. 5). In the San Joaquin Basin 

the metamorphic rocks are represented by a series of 

relatively small disconnected bodies. Still farther to 

the southeast, in the basins of the Kings, Kaweah, and 

Kern Rivers, they again occur in larger masses along 

the lower west slope. Accordingly it would appear 

that the San Joaquin Basin, of all the drainage basins 

in the central and south-central part of the Sierra 

Nevada, is the one in which so far as the lower west 

slope is concerned the metamorphic rocks comprise 

the least, and the batholithic rocks the greatest proportion of the area.

In the foothills section between the San Joaquin 

and the Kings Rivers, the metamorphic rocks of 

Paleozoic and Mesozoic age occur in tightly folded 

anticlines and syncliiies which strike northwestward 

(Macdonald, 1941, p. 217, 270-2 2). The oldest division of the metamorphic sequence is a metasedimentary 

series between 20,000 and 30,000 feet thick, consisting 

chiefly of mica schist. Above this is a metavolcanic 

series at least 10,000 feet thick containing minor 

amounts of iiiterbedcled metasediments. The volcanic 

rocks, which are intermediate to basic, have been 

converted into plagioclase amphibolite and amphibole 

schist. The youngest division of the metamorphic 

sequence is another metasedimentary series close to 

10,000 feet thick, consisting mainly of mica schist. Sills 

of serpentine and a few bodies of olivine gabbro have 

been metamorphosed to a degree comparable with the 

surrounding rocks.

The body of metamorphic rocks in the Mount Ritter 

region is the largest in the basin. This body, in its 

broader relations, is the expanded southern part of the 

narrow belt of metamorphic rocks, of Mesozoic age,

which extends for about 40 miles along the crest of 

the range, at the heads of the Tuolumne, Merced, and 

San Joaquin Basins (Jenkins, 1938). The body is 

irregular and measures about 12 miles across in its 

larger dimensions. It forms the bulk of the Ritter 

Range, and extends across both the Middle Fork and 

the North Fork Canyons. At the northeast it passes 

beneath Tertiary lavas capping the main divide.

The rocks of the Mount Ritter region have been 

described by Erwin (1934, 1937) and also considered 

in the regional studies by Mayo (1935,1937, and 1941). 

They consist mainly of intensely folded metavolcanic 

rocks which form an almost isoclinal series striking in 

general N. 30° - 40° W. The metavolcanic rocks, predominantly pyroclastic rocks, include diverse rock 

types altered into schists and, particularly, mylonites. 

There are minor intercalations of metasediments, and 

Erwin has mapped these separately in the upper Middle Fork basin.

In the Middle Fork basin, the metavolcanic rocks, 

being of various hues, give the landscape a distinctively 

banded appearance which contrasts with the uniformly 

dark or light aspect of nearby areas. The Ritter 

Range looms almost black above the light-colored 

granitic rocks to the south and southwest. Its rocks, 

mostly metatuffs and breccias, are generally more massive than those in the Middle Fork basin, and apparently less severely metamorphosed. In the North Fork 

basin and to the west of it, the metamorphic rocks 

again are more completely altered and more schistose 

than in the Ritter Range.

Between Mono and Bear Creeks, metavolcanic rocks 

of Mesozoic age reappear in a long narrow belt which 

extends southeastward along Goddard Canyon (Jenkins, 1938). This belt reaches far beyond the limits of 

the San Joaquin Basin, continuing, with some interruptions, across the Kings River Basin to the headwater area of the South Fork of that river.

The rocks of this belt, presumably Mesozoic in age, 

have not been fully mapped or studied in detail. They 

crop out along Goddard Canyon and make up a considerable part of both the Goddard Divide and the 

LeConte Divide. Where observed in the course of 

this reconnaissance they consist predominantly of intricately folded, nearly vertical metavolcanic schists 

striking northwestward.

Other smaller masses of metamorphic rock lie widely 

scattered within the San Joaquin Basin, some in belts, 

others without apparent system. The mountains of 

Kaiser Ridge, west and northwest of Nellie Lake, are 

composed largely of quartzite which disintegrates into 

angular blocks less than 2 feet across, contrasting with 

the much larger and more rounded granite boulders
18 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

of nearby areas. The peak (altitude 9,622 feet) north 

of the lake is composed partly of quartzite, partly 

of granite; the extreme summit is granite. Farther 

east, Kaiser Peak itself is composed of thinly bedded 

quartzite and schist. On the north side of the peak 

these rocks are cut by thick sills of granite and aplite. 

The quartzite on the east spur of Kaiser Peak breaks 

down into distinctive small fragments. The Twin 

Lakes are bordered on the north by a belt of crystalline 

limestone forming an arc-shaped outcrop more than 

1 mile long, the concave side of which is toward the 

northeast. The peak east of Potter Pass is composed, 

in its eastern part, of closely plicated grayish-green 

schist.

Small bodies of metamorphic rock, mostly schist, 

were also observed on the east side of Silver Creek, 

% mile above its junction with Fish Creek; at the east 

end of Junction Bluffs; % mile northwest of Clover 

Meadow Ranger Station; on Green Mountain, 1% 

miles north of Soldier Meadow; and in Shakeflat Creek 

basin, as well as on the ridge to the southwesl of it, 

where the local rock is largely schist and quartzite. 

Similar small bodies of metamorphic rock undoubtedly 

occur at many other places in the San Joaquin Basin.

VOLCANIC BOCKS

The volcanic rocks, scattered from the Sierra crest 

to the western foothills, occur in many small patches 

whose aggregate area is only a minor part of the San 

Joaquin Basin. In age they range from Miocene to 

late Pleistocene or perhaps even to Recent. Unlike 

the extensive flows in the northern half of the range, 

they have interfered but little, and only locally, with 

the orderly development of the valleys and canyons.

The principal areas of volcanic rocks lie on the main 

divide adjacent to the Middle Fork Canyon, and 

farther south within the canyon. This region, included 

in the southeastern part of the Mount Lyell quadrangle, has been mapped by Erwin (1934) who distinguished 5 volcanic units, 2 of late Miocene age and 

3 of Pleistocene age.

The older Miocene unit, consisting of basalt flows, 

includes a relatively large occurrence east of the Middle 

Fork Canyon (southeast of Agnew Pass) ; also remnants south of Iron Mountain between the North and 

Middle Forks of the San Joaquin River, in the upper 

East Fork of the Granite Creek basin, in the vicinity 

of Clover Meadows, and elsewhere. At the Middle 

Canyon locality the basalt rocks are exposed in cross 

section, giving a bold, steplike profile to the east side 

of the canyon. The flows vary in number from place 

to place; in the thicker sections they "do not exceed 36"

FIGURE 9. Ice-truncated columns of basalt on the Devils Postpile. 

Some of the facets are rounded and polished by the ice.

(Erwin, 1934, p. 46). North of Agnew Pass their 

aggregate thickness is estimated to be more than 1,500 

feet. The flows, which have columnar or blocky jointing? permit surface water to seep through to the underlying metamorphic rocks, whose surface is followed 

to Middle Fork Canyon. Here, emerging from beneath 

the lavas, the water gives origin to most of the streams 

on the east side of the canyon. The other lava caps 

in the region are of similar character but smaller.

The younger Miocene unit includes andesitic flows, 

with a maximum thickness of about 1,000 feet, which 

overlie the basalt on the Sierra crest, east of Middle 

Fork Canyon. A few miles farther southeast, andesites 

also make up the bulk of Mammoth Mountain, an 

isolated and deeply eroded preglacial volcano which 

Mayo (1941, p. 1068) has termed "the most impressive 

volcanic edifice in the region."

The three Pleistocene units are basalt flows, tuffs, 

and pumice. There are several occurrences of the 

basalt, the most important being a Y-shaped mass 

immediately west of the Sierra crest. The converging 

arms of the Y, each about 3 miles long, extend southward from the head of Pumice Flat and westward 

from Mammoth Pass, and unite just below Reds 

Meadow to form the upright, which extends southsouthwestward about 4 miles farther. This mass includes the Devils Postpile (Matthes, 1930b) (fig. 9). 

A short distance below the Postpile a cliff of the basalt 

gives rise to Rainbow Falls, 150 feet high, the most 

notable waterfall in the San Joaquin Basin (fig. 10). 

The basalt appears to have descended from the vents 

at Red Cones and Pumice Butte, and from a fissure 

near Mammoth Pass.5 It issued after the El Portal 

glacial stage onto the glaciated surfaces of Middle

5 Location of these and other volcanic vents is shown on Erwin's 

map, also on pi. 3 and fig. 6 of Mayo's report, Deformation in the 

interval Mount Lyell Mount Whitney, California (1941).
GEOMORPHOLOGY 19

FIGURE 10. Rainbow Falls, a short distance below the Devils Postpile 

on the Middle Fork of the San .Toaquin River. The falls, 150 feet 

high and the most spectacular in the region are produced where the 

river leaps over the edge of a basalt cliff.

Fork Canyon, accumulating to depths of 100 to 700 

feet. When the Middle Fork glacier readvanced in the 

Wisconsin stage, it removed all but the more obdurate 

parts of the lava (Matthes, 1930b, p. 5).

The other Pleistocene volcanic units consist of an 

area of crystallithic tuff in the vicinity of Satcher 

Lake and Reds Meadow, and a scattering of pumice 

pellets, as much as 1 inch in diameter, widely distributed throughout the region and particularly abundant between Agnew Meadows and Pumice Butte. 

Erwin considers the pumice to be "younger than older 

glacial material."

In this reconnaissance several volcanic cones and 

many small patches of volcanic rock were noted. 

Black Point, iy2 miles west of Huntington Lake, is 

a small volcanic cone. Another cone, Brown Cone, 

lies to the north of Kaiser Creek; still another is 

situated in nearby Cow Meadow. The latter is the

remnant of an andesitic eruption crater, the west and 

north sides of which are best preserved. About 3 

miles farther southeast is another small andesitic volcano which is probably iiiterglacial, because granite 

erratics left by the Wisconsin stage rest on its lava. 

The volcano stands about 100 feet above the surrounding country, and contains a shallow lake in what appears to be a compound crater.

Of the many scattered patches of volcanic rock 

observed, mention may be made of several in the lower 

South Fork Canyon; also those in the vicinity of Pincushion Peak, particularly west of the summit; those 

at the northwest md of Mono Ridge, one of them 

giving rise to the eminence called Volcanic Knob; 

several extending from Onion Spring Meadow southwestward almost to the South Fork of the San Joaquin 

River; the patches in upper Big Creek Basin which 

form Chinese Peak, Red Mountain, and Black Peak 

(fig. 47); an occurrence in Chiquito Creek basin, 1 mile 

northwest of Placer Ranger Station; and the patches 

which partly cap the summit of Squaw Dome. In the 

case of Chinese Peak, three large dikes radiate from the 

central summit.

Though none of the occurrences mentioned has been 

studied in detail, most of them apparently are andesitic. 

However, patches of olivine basalt (Miocene or 

Pliocene; which cap Table Mountain and a few other 

foothills in the Friant and Academy quadrangles are 

described by Macdonald (1941, p. 266 and folded map).

GEOMORPHOLOGY

The west slope of the Sierra Nevada, of which the 

San Joaquin Basin forms a part, is a region of 

exceptional interest to the geomorphologist, both in 

its broader aspects and in its details. Although furrowed by many deep canyons, it nevertheless retains 

on its undissected intercanyon uplands considerable 

remnants of ancient erosion surfaces, as well as lofty 

monadnock ridges with occasional tabular summits. 

These features, together with the evidences of Pleistocene glaciation in the higher portions, present a decipherable, if partly obscured, record of the geomorphologic history of the range. Moreover, as the rise 

of the Sierra Xevada was intimately related to the 

earth movements that affected the Great Basin, to the 

east, and as, furthermore, the growing height of the 

range brought upon that province the stark aridity 

that has so profoundly influenced its erosional development, it will be apparent that the story to be read in 

the features of the west slope of the Sierra Nevada 

has bearings that extend far beyond the confines of 

the range.
20 GEOMOEPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

The precipitous east front of the Sierra Nevada, 

though extremely impressive, is to the geomorphologist 

less instructive than the gently declining west slope. 

The product of essentially one episode in the life 

history of the range, and that a relatively recent one, 

the east front tells a rather short and simple story. 

The west slope, on the other hand, recounts a long 

history reaching back into the beginning of the 

Tertiary period; and it even retains sculptural and 

drainage elements which were inherited from an 

ancient mountain system of Appalachian type, that 

occupied the site of the present Sierra Nevada during 

the Cretaceous period.

The west slope of the Sierra Nevada is the only 

large area of elevated land in the United States west 

of the Rocky Mountains that presents such a comprehensive geomorphic record in fairly readable form. 

Primarily because of its great areal extent it has escaped thorough dissection in spite of strong uplift 

and consequent vigorous erosional attack. By comparison with the Sierra Nevada, the back slopes of 

the Basin Ranges are of very limited extent, measuring, 

as a rule, only 4 to 6 miles from crest to base. The 

Sierra back slope, however, measures 40 to 60 miles 

from crest to base, and in the distance of 430 miles 

through which it maintains this breadth is traversed 

by rivers as long as 100 miles. Even if the northernmost and southernmost portions, which are complicated 

by lines of dislocation, are subtracted, the west slope 

remains by far the largest sharply delimited unit area 

of uplifted and tilted earth surface in the western 

United States. The Cascade Range, it is true, covers 

a greater area than the Sierra Nevada, but most of 

its elevation is due to irregular upwarping. Its surface 

configuration in addition reflects the vagaries of volcanic action and scarcely offers an advantageous field 

for geomorphologic studies of a broad regional nature.

Three factors besides areal extent have retarded 

the dissection of the west slope of the Sierra Nevada: 

first, the resistance to erosion of the harder metamorphic rocks and the sparsely jointed, massive granitic 

rocks that prevail over large areas; second, the general 

absence, except in the northernmost and southernmost 

parts of the range, of lines of dislocation that facilitate 

localized trenching; and third, the protection against 

gullying erosion which its soil and its vegetation afford, 

and which probably always have afforded, except in 

the crestal parts which were severely glaciated during 

Pleistocene time and have since remained barren because of their altitude. In the latter respect the Sierra 

Nevada stands in marked contrast to the naked, craggy 

flanks of the Basin Ranges, which are fully exposed 

to the processes of denudation.

COMPARISON OF SECTIONS OF THE SIERRA WEST 

SLOPE

Before narrowing consideration to the San Joaquin 

Basin, it will be profitable to consider the various 

sections of the west slope of the Sierra Nevada as a 

whole, both to the north and to the south of the basin, 

in regard to the problems they present with reference 

to geomorphologic analysis.

The northern two-fifths of the Sierra Nevada, extending approximately as far south as the northwestern boundary of Yosemite National Park, is in 

large part mantled with volcanic agglomerate and 

lava, with the result that its earlier erosion surfaces 

are almost completely obliterated. The buried valleys 

and ridges can be glimpsed here and there in the sides 

of the newer canyons that trench through the volcanic 

cover, but the glimpses thus afforded hardly suffice to 

permit reconstruction of the ancient landscapes with 

any degree of confidence. Moreover, several northwestward-diverging faults of considerable throw disrupt the unity of the west slope at the northern end 

of the range, thereby complicating the geomorphologic 

record.

The southern one-fifth of the range, from the Kern 

Canyon south to the Tehachapi Pass, is traversed by 

several lines of faulting which, though not seriously 

affecting its unity, nevertheless control some of the 

principal drainage lines and have influenced erosion. 

Furthermore, this part of the range does not slope 

gently toward the western foothill belt, but has the 

aspect of a profoundly dissected horst that breaks off 

abruptly at its western as well as its eastern margin.

The upper Kern Basin is probably unsurpassed for 

simplicity of sculpture; probably no other part of 

the range retains erosion surfaces which so clearly 

exhibit the effects of incomplete cycles of erosion as 

does this basin, in which Lawson (1904, 1906) made 

his classic morphologic analysis. But the precise correlation of these erosion surfaces with those in the 

central part of the range presents difficulties, for in 

several respects the Kern River is anomalous among 

the master streams of the Sierra Nevada. Its course 

appears to have been determined largely by structural 

factors, rather than by tilting of the Sierra block; 

for it flows southward along a zone of faulting, in a 

course that trends parallel to the crestline of the range 

instead of normal to it, as in the case of the other 

master streams. Furthermore, the Kern River traverses that part of the range wherein a transition 

takes place from tilted block structure at the north 

to horst structure at the south; and in the lowermost 

part of the Kern Basin there are other structural irregularities. The tributaries of the Kern River trend
GEOMORPHOLOGY 21

in various directions, without apparent system, rather 

than in patterns decipherable in terms of the early 

geomorphologic history of the basin. It appears, 

therefore, that the Kern River Basin is hardly typical 

for the range as a whole, but presents a rather special 

case, complicated by several local factors.

It is in the central and south-central parts of the 

range that the geomorphologist finds the conditions 

most favorable for his purpose. More specifically this 

area extends from the northwestern boundary of the 

Yosemite National Park southeastward to that spur 

ridge in Sequoia National Park known as the Great 

Western Divide, and it comprises the drainage basins 

of the Tuolumne, Merced, San Joaquin, Kings, and 

Kaweah Rivers. This part of the Sierra Nevada, 150 

miles long in the direction of its axis and averaging 

60 miles in breadth, appears to have been essentially 

a single massive rigid block, and has remained relatively free from deformation or fracturing except locally, as at its western margin. The drainage system 

of the west slope of this portion of the range, so 

far as known, has not been dislocated or rearranged 

in consequence of either faulting or warping, except 

in a minor way as in certain parts of the foothill belt. 

Neither have any of its streams been eliminated or 

significantly diverted by extensive volcanic outpourings 

such as prevailed in the northern parts of the range. 

Local extrusions have not been wanting in various 

places and at different times, but the drainage changes 

caused by them have been inconsequential.

One drainage basin, that of the Merced River, has 

remained free from volcanic outpourings, containing 

only one diminutive crater. As a consequence, within 

its confines, the processes of stream erosion have 

worked without interference, except by the glaciers 

of the Pleistocene epoch, ever since the earliest recognized cycle. Nevertheless, the Merced Basin is not 

the simplest field for geomorphologic study on the 

west slope, for its central feature, the Yosemite Valley, 

is of a peculiarly enigmatic sort (Matthes, 1930a). 

It is a chasm of aberrant type in whose interpretation 

the geomorphologist can hardly hope to succeed without having first gained an insight into the history 

of the more normally shaped canyons of the west 

slope. Furthermore, the lower half of the Merced 

Basin, being composed of upturned strata of thinbedded metamorphic rocks that differ sharply in resistance to erosion, is dissected by a maze of valleys 

and gulches, and retains on its skeleton ridges few 

recognizable remnants of the more ancient erosion surfaces. The profiles of the Merced River for each 

of two earlier erosion cycles can be reconstructed with 

some confidence throughout the upper half of the

basin, which is composed almost wholly of granitic 

rocks. However, these profiles cannot be extended for 

any great distance down through the lower half, for 

lack of reliable diagnostic features in its greatly dissected topography. It was because of these baffling 

circumstances that the author deferred publication of 

his conclusions regarding the history and mode of 

development of the Yosemite Valley until he had had 

opportunity to test their validity by comparative 

studies of other major canyons in the range, not only 

of those that possess Yosemite-like widenings but also 

those that are normally shaped throughout.

Reconnaissance for this purpose in the Tuolumne 

Basin (1916,1917, and 1919), which adjoins the Yosemite region on the north and northwest, afforded an 

opportunity to examine the Hetch Hetchy Valley, 

which is most closely analogous to the Yosemite Valley. 

The outstanding lesson of Hetch Hetchy was that the 

geoinorphic history is by no means recorded with equal 

clearness in all parts of the Sierra Nevada, for in 

some parts it may be extremely obscure in spite of the 

grand scale on which the features of the landscape 

are modeled. The Tuolumne Basin, though rich in 

glacial features, did not prove especially helpful in 

defining successive landscapes produced by successive 

cyles of erosion, for it contains few well-preserved 

remnants of ancient surfaces of erosion, and is poor in 

clean-cut hanging valleys whose discordance is demonstrably due to preglacial canyon cutting. Over considerable parts of the Tuolumne Basin the granitic 

rocks have the same unusual structure as in the Yosemite region, and have given rise to similar aberrant 

sculptural forms. The Hetch Hetchy Valley is another 

yosemite, although of smaller dimensions than its 

prototype.

The Table Mountain region (fig. 1), visited in 1921, 

on the divide between the lower Tuolumne and lower 

Stanislaus canyons, proved to be an unexpectedly fruitful field because the gravels in some of its lavaentombed stream channels yielded well-preserved fossils that afford a means for determining the age of one 

of the older erosion surfaces. (See p. 23.) Farther 

north, however, the older topographic features are 

largely buried under the mantle of volcanic rocks.

Just south of the San Joaquin Basin, the writer's 

investigations have indicated that in the basins of the 

Kings and Kaweah Rivers, likewise, there are conditions which interfere with geomorphologic analyses 

of a broadly regional character, notably that these 

basins exhibit relatively few of the well-preserved 

hanging valleys which are of critical importance in 

deciphering the successive events of the history of 

the range.
22 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

SUITABILITY OF THE SAN JOAQUIN BASIN FOR 

GEOMORPHOLOGIC ANALYSIS

The broad San Joaquin Basin appears in some 

ways to be the most revealing drainage basin of the 

west slope in regard to features that aid in the interpretation of regional geomorphologic problems. 

Briefly stated, its importance in this respect stems from 

the following combination of circumstances:

The erosional features of the basin are unobscured 

by volcanic flows except in relatively small areas.

The granitic rocks, exceptionally extensive in this 

basin, are prevailingly massive and exert profound 

influence on the topography. The San Joaquin Canyon 

is, therefore, consistently narrow, and exhibits neither 

anomalous Yosemite-like widenings nor, for the most 

part, the unusual sculpturing characteristic of the 

yosemites. Furthermore, the resistant nature of the 

massive granitic rocks accounts for the preservation of 

an exceptionally fine record of the successive cycles of 

erosion, and an extraordinary wealth of clean-cut hanging side valleys.

The granitic rocks are practically continuous to the 

foot of the range. Consequently, the ancient erosion 

surfaces and the array of hanging valleys likewise 

extend not merely throughout the manifestly glaciated 

upper course of the San Joaquin Canyon but also 

through the unglaciated lower course in fact to within 

a few miles of the foothills.

The San Joaquin River has an essentially normal 

southwestward course. Thus flowing down the slope 

of the Sierra block, the river must have received the 

entire effect of the rejuvenation caused by each tilting 

movement. In contrast, the tributaries of the San Joaquin River for the most part have northwesterly or 

southeasterly courses, substantially at right angles to 

the master stream as well as to the direction of tilting 

of the block. The flow of the tributaries, therefore, 

must have been only mildly accelerated by the tilting 

of the Sierra block. In this contrasting relationship 

of master stream to tributaries, the drainage pattern 

of the San Joaquin Basin is typical for most of the 

basins in the central and southern part of the Sierra

Nevada, but probably in no other basin is the relationship so well shown.

Finally, it may be noted that in the San Joaquin 

Basin the erosion surfaces form broad uplands which 

bear lofty monadnock ranges. The erosion surfaces 

of the uplands have remained essentially undisturbed 

because of the resistant nature of the bodies of massive 

granitic rock which underlie them. The monadnock 

ranges, by their position and prevailingly northwestward trends, are representative for the Sierra Nevada 

as a whole, and significant in the interpretation of its 

early geomorphic history. Moreover, by their great 

height above the erosion surfaces which surround them, 

they testify, more clearly than does the evidence which 

the author has observed in other parts of the range, 

to the relatively great antiquity of that most ancient 

erosion surface which is still identifiable from small 

but sharply defined remnants preserved on a few of the 

summits.

SUMMARY OF CONCLUSIONS CONCERNING THE 

YOSEMITE REGION

A primary purpose in undertaking studies in the 

San Joaquin Basin was to test the soundness of conclusions reached in the Yosemite region regarding the 

geomorphologic development and the glaciation of that 

region, and to determine the bearing of these conclusions on the history of the Sierra Nevada in general. 

It is appropriate, therefore, to summarize the results 

of the author's study of the Yosemite Valley (Matthes, 

1930a). (See fig. 11.)

The most significant conclusions relate to the origin 

and significance of the hanging side valleys of the 

Yosemite chasm. Detailed mapping of the morainal 

system of the ancient Yosemite Glacier indicated that 

that glacier never extended more than a mile beyond 

the site of El Portal. The hanging side valleys of the 

Merced Canyon below El Portal do not hang, therefore, because of any glacial deepening which that canyoii has undergone. The explanation was offered that 

they hang because their streamlets have been unable to 

trench as rapidly as the Merced River since the reFIGURE 11. Idealized profile showing features produced by successive cycles of erosion in the Yosemite region. E, tabular remnant of Eocene 

surface on high residual peak ; R, residual peak no longer bearing remnants of Eocene surface ; M, Miocene surface preserved on intercanyon uplands; J/', longitudinal profiles of hanging valleys of Miocene cycle (glaciated in the High Sierra) ; If", reconstructed cross 

profiles of main valleys of Miocene cycle; PI, main valley of Pliocene cycle (glaciated) ; PI', longitudinal profile of hanging valley of 

Pliocene cycle; PI", reconstructed cross profile of main valley of Pliocene cycle; Pleistocene gorge of Pleistocene cycle (unglaciated). 

Vertical scale same as horizontal scale. Prom 16th International Geological Congress, Guidebook Ifi. p. 35, 1933.
GEOMORPHOLOGY 23

juvenation of the Merced by the last uptilting of the 

Sierra Nevada. The streamlets were handicapped not 

only by their comparatively small volume but also by 

the fact that their courses trend northwestward and 

southeastward, substantially at right angles to the direction of the tilting, and therefore have remained 

essentially unsteepened, whereas the Merced's course 

trends southwestward, directly down the slope of the 

Sierra block, and therefore has been appreciably 

steepened.

Projection of the longitudinal profiles of these hanging valleys forward to the axis of the Merced Canyon 

shows that they are closely accordant in height. Their 

profiles indicate a series of points on a former profile 

of the Merced with respect to which the side streams 

had graded their courses prior to the last uplift. This 

old profile can be extended upward into the glaciated 

part of the Merced Canyon above El Portal and even 

into the profoundly glaciated Yosemite Valley, accordant points being furnished by a number of hanging side valleys (due allowance being made for the 

effects of glacial erosion on those valleys).

However, not all hanging valleys of the Yosemite 

region are accordant with this set. Several constitute 

a separate set indicating another old profile of the 

Merced at a level 600 to 1,000 feet higher than the first. 

Others point to an old profile of the Merced about 

1,200 feet lower than the first. There are thus three 

distinct sets of hanging valleys produced in three cycles 

of erosion. Those of the upper set, like those of the 

middle set, were left hanging as a result of rapid 

trenching by the Merced induced by an uplift of the 

range, there having been two such uplifts. Only the 

valleys of the lower set hang because of glacial deepening and widening of the Yosemite Valley, the cycle 

in which they were cut having been interrupted by the 

advent of the Pleistocene glaciers.

During the remote cycle of which the hanging valleys of the upper set and the undulating Yosemite 

upland are representative, the Yosemite Valley itself 

was broad and shallow, postmature in form. That 

early stage in its development, accordingly, is called 

the broad-valley stage. The deeper hanging valleys of 

the middle set were graded with respect to a deeper 

Yosemite Valley of submature form which must have 

had the aspect of a mountain valley. That stage in its 

development is therefore called the mountain-valley 

stage. The short, steep hanging valleys of the lower 

set and certain topographic features associated with 

them show that during the third cycle of erosion the 

Yosemite Valley was a roughly V-shaped canyon with 

a narrow inner gorge. This stage, which immediately

preceded the glacial epoch, is therefore called the 

canyon stage.

In the Yosemite region, paleontological evidence 

for the age of the upland erosion surface is lacking, 

but farther north, in the Table Mountain district between the Tuolumne and the Stanislaus Rivers (figs. 1, 

12), lava-entombed stream channels correlative with 

the upland have yielded well-preserved impressions of 

leaves and a few mammalian remains. These fossils, 

according to determinations by Ralph W. Chaney 

and Chester Stock, date back to the later part of 

the Miocene epoch (Matthes, 1930a, p. 1, 28; 1933a, 

p. 35, 70). Accordingly, the upland erosion surface in 

the Yosemite region is thought to be of late Miocene 

age. Uplift of the Sierra Nevada at the end of the 

Miocene epoch initiated the next cycle, during which 

the mountain-valley stage was evolved. That cycle 

lasted presumably through most, if not all of, the 

Pliocene epoch. The canyon stage was produced in 

all probability during the Quaternary period.

The excellent preservation of the hanging valleys 

of the upper set, in spite of their great age, is explained 

by the exceedingly resistant nature of the massive 

granite that underlies them. The valleys of the middle 

set were carved in prevailing jointed rocks that were 

less resistant to stream erosion, and the gulches of the 

lower set were carved in closely fractured rocks in 

which the streams eroded with relative ease.

The gradients of the two higher profiles of the 

Merced furnish data from which the amplitude of each 

of the two great uplifts of the Sierra Nevada can be 

roughly calculated. The uplift at the end of the 

Miocene epoch added about 3,000 feet to the height 

of the range; the uplift at the end of the Pliocene 

epoch added 6,000 feet more. These determinations 

rest on deductions made after the reconnaissance of 

the San Joaquin Basin was completed, and which took 

into consideration the Tertiary profiles of the San 

Joaquin River and the rivers of the northern Sierra 

Nevada as well as those of the Merced River (Matthes, 

1930a, p. 44).

Of the earlier geomorphologic history of the Yosemite region a glimpse is afforded in the explanation 

of the origin of the southwesterly course of the Merced 

River and the arrangement of the lesser tributaries at 

right angles to it. The Merced River established its 

course conformably to the southwesterly slant of the 

Sierra region, presumably early in the Tertiary period, 

when there still existed remnants of a system of northwestward-trending mountain ridges of Appalachian 

type, which had been formed at the end of the Jurassic 

period by the folding of sedimentary and volcanic 

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FIGURE 12. Section through Table Mountain region, Sierra Nevada. PI, Pliocene surface of erosion developed on unressistant slates and volcanic rocks 

M, residual mountains bearing remnants of Miocene surface; M', reconstructed hills on Miocene surface flanking the ancient valley through which 

flowed; T, reconstructed portions of Table Mountain flow. Beneath the columnar latite of Table Mountain is the gravel of the buried river channe

gold. The Stanislaus and Tuolumne Canyons were cut during the Pleistocene cycle. Vertical scale is twice the horizontal scale. From 16th Inter

Guidebook 16, p. 36, 1933.
GEOMORPHOLOGY 25

Friant (see Friant quadrangle), dominates the foothills roundabout with an altitude of 1,611 feet and 

stands 1,180 feet above the neighboring valleys, but 

its height is exceptional. Immediately south of it, the 

country drops off to levels of 600 and 500 feet, and 

only small rocky knobs, a few tens of feet high, rise 

above the level of the plain, which here is about 450 

feet above sea level.

A conspicuous feature of the foothill belt is the 

series of flat-topped hills, or mesas, capped by volcanic rock, that extends in a southerly direction 

athwart the southwesterly course of the San Joaquin 

River. Like other volcanic mesas of this type farther 

north in the foothill belt of the Sierra Nevada, these 

are collectively known as Table Mountain. (See Millerton Lake and Academy quadrangles.) The partly 

disconnected mesas have an aggregate length of 16 

miles, of which somewhat more than 6 miles lies on 

the northwest side of the river and the balance on the 

southeast side. Where the San Joaquin River transects the series of mesas, the river bed is fully 1,700 

feet below the surface of the ancient lava flow. West 

of the river near the outer fringe of the foothills, is 

another lower and less well preserved series of flattopped hills known as Little Table Mountain. (See 

Lanes Bridge quadrangle.) This series is only 5 

miles long and extends in a south-southeasterly direction, ending about 4 miles below Friant in a bluff 

overlooking the river.

The plain immediately in front of the debouchure 

of the San Joaquin River consists of a great alluvial 

fan built by the river. This fan extends westward 

and southwestward for about 30 miles out from the 

foothills. At Friant, near the apex of the fan, the 

surface is 460 feet above sea level. Thence it slopes 

down to an altitude of about 200 feet at its outer 

margin. So gentle is this slope that to the traveler's 

eye the surface appears utterly flat. The city of 

Fresno stands near the middle of the fan, about 17 

miles below the apex and 6 miles south of the river.

A number of radiating and usually double-crested 

ridges on the surface of the fan indicate natural levees 

along old channels which the river, or branches of it, 

have occupied at different times. Although the eye 

hardly detects these features, they stand clearly revealed on the detailed topographic maps, on which the 

contour lines are drawn at intervals of 5 feet. (See 

Friant, Lanes Bridge, Clovis, Bullard, Herndon, Biola, 

Gravelly Ford, Kerman, Kerney Park, Fresno, and 

Malaga quadrangles.)

These ridges are of the type which Kirk Bryan 

(1923, p. 29) noted in the Sacramento Valley and has 

called "channel ridges." Most of the old stream channels are now dry, but oome have been improved and 

are being used as irrigation ditches.

In geologically Recent time the San Joaquin River 

has cut a trench in its great fan. This trench is 155 

feet deep at Friant; thence downstream its depth 

diminishes progressively to only a few feet at the margin of the fan. The trench varies in width from y2 

to 2 miles and contains several terraces marking successive stages in its cutting.

SAN JOAQUIN CANYON AND ITS MAIN BRANCHES

The canyon of the Sail Joaquin River (figs. 13-15) 

is neither among the deepest nor shallowest of the 

canyons in the west slope of the Sierra Nevada, but is 

in an intermediate class. It is not to be compared 

with the canyon of the Kings River, which attains 

the prodigious depth of 8,000 feet, nor with the canyons 

of the Tuolumne and Kern Rivers, which are between 

4,000 and 5,000 feet deep. On the other hand, the San 

Joaquin Canyon is not to be classed with the trenches 

of the Feather, Yuba, American, Mokelumne, and 

Stanislaus Rivers, in the northern half of the range, 

which scarcely exceed 3,000 feet in depth. It falls, 

rather, in that middle class to which the Merced 

Canyon also belongs. The latter, though less than 

3,000 feet deep in its lower course, reaches depths of 

4,000 feet and locally, of 4,800 feet, in the Yosemite 

region.

The San Joaquin Canyon ranges for the most part 

between 3,000 and 4,000 feet in depth below the flanking uplands, but it exceeds 5,000 feet in depth, on the 

east side at least, for several miles in its middle course 

above and below the mouth of Big Creek. Its depth 

increases to 5,800 feet opposite the platform west of 

Huntington Lake, and a few miles farther up it reaches 

a maximum of 6,800 feet opposite the westernmost 

summit of Kaiser Ridge. On the west side, the nearest 

summit of the Chiquito Ridge rises 5,100 feet above the 

river, but the canyon side there is broken at a height of 

2,200 feet above the river by a broad upland bench. 

Immediately above this deep portal between the Chiquito Ridge and the Kaiser Ridge the depth of the 

canyon again diminishes to an average of 3,000 feet, 

and that depth is maintained as far as the junction 

of the Middle and South Forks.

Of special geomorphologic significance is the fact 

that the San Joaquin Canyon has a distinct 2-story 

form throughout the greater part of its length (fig. 13). 

It has the appearance of a deep mountain valley of 

mature form, with moderately steep, forested sides, in 

whose broad floor a narrow, sheer-walled inner gorge 

of approximately equal depth is cut. This 2-story 

aspect begins a short distance above the foothills, about
26 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

FIGURE 13. View down San Joaquin Canyon from B.M. 4112 on road 

to Hogue Ranch. The railroad, barely discernable on the far side 

of the canyon (see arrow), follows a sloping bench (Pliocene surface) above the gorge (Pleistocene canyon), and a corresponding 

bench on the near side of the gorge appears in the lower part of 

the photograph.

a mile above Auberry. There, a well-defined gently 

sloping bench, representing a strip of floor of the 

mountain valley, appears at a height of 1,200 feet 

above the river. This bench extends 15 miles along 

the east side of the canyon to the tributary canyon of 

Big Creek. It varies in width from a hundred yards 

to a mile, the average being well over a half mile. 

Uninterrupted by any deep-cut side gorges, it afforded 

an excellent location for the San Joaquin and Eastern 

narrow gage railroad which formerly led to Cascada 

Station (Big Creek Post Office).

The height of this bench above the canyon bottom 

increases progressively upvalley to 1,800 feet in the 

Jose Basin and to 2,200 feet just below the side canyon 

of Big Creek. The upland in turn rises fully 2,000 

feet above the bench. Some of the mountains on the 

upland surface rise higher yet. Music Peak stands 

2,800 feet above the bench; Mount Stevenson 3,000 

feet.

On the west side of the canyon a similar bench 

begins near Oat Mountain, and thence extends up 16 

miles to the hanging valley of Shakeflat Creek. It 

is more irregular than the bench on the east side, its 

surface being diversified by alternating spurs and shallow transecting valleys, yet its average height above 

the canyon bottom corresponds to that of the eastern 

bench and, like the latter, increases gradually upvalley. 

To the west, wT ooded slopes of moderate declivity rise 

1,500 to 2,500 feet to the uneven surface of the upland. 

Neither of the two benches persists clearly defined all 

the way up to the junction of the Middle and South 

Forks. The eastern bench is but feebly developed 

above Big Creek, and the western bench is scarcely 

traceable above Shakeflat Creek. Nevertheless, most

FIGURE 14. View in San Joaquin Canyon below mouth of Stevenson 

Creek, looking downstream. A few exfoliation shells cling to the 

massive granite walls. The white streak on the left is a streamlet 

that glides down the smoothly curving surface of the rock.

of the inner part of the canyon beyond these points 

is steeper sided and more gorgelike than the outer 

part.

The inner gorge 6 is narrowest and most conspicuous] y sheer walled in that part of the San Joaquin 

Canyon where the flanking benches are most prominent. 

Indeed, in the 5-mile stretch from Mill Creek to a 

point below the mouth of Big Creek (fig. 14) it is 

so constricted that in its natural state, before the road 

wT as built, the gorge was utterly impassable. Even 

the engineers who surveyed the course and profile of 

the San Joaquin River for the U. S. Geological Survey, 

although experienced in making their way up the 

rough, bouldery beds of mountain torrents, were balked 

by this exceedingly narrow portion of the San 

Joaqum's gorge, and wT ere obliged to carry their line 

over the flanking benches. In several places, the walls 

of bare massive granite descend to the rock channel of 

the brawling stream with marvelously smooth convexly 

curved profiles that are steepest at the bottom.

6 In his field notes Matthes describes features that suggest that the 

inner gorge of the lower San Joaquin Canyon is a two-storied affair, 

but he does not incorporate this suggestion in the rough draft which 

formed the basis for this report. To put his observations on record, 

they are herewith quoted:

"Below the mouth of Big Creek, [San Joaquin Canyon is] narrow, 

V-shaped. River runs in rock cut channel. Granite prevailingly 

massive, exfoliating on large scale. Well-defined shoulders about 500- 

600 feet up. Apparently indicative of an old valley floor. These 

shoulders, however, are themselves about 1,000 feet below mouths of 

late-Pliocene hanging valleys. Lowermost part of shoulders prominent 

on west side of canyon, north of Italian Bar (2,100 feet). Also on 

south side, east of mouth of Mill Creek. Road built on this shoulder. 

Shoulders of corresponding height (about 400 feet above river) north 

of mouth of Big Creek. Would seem to indicate renewed tilting of 

Sierra late in Pleistocene. Farther down river these shoulders are 

not marked or [are] entirely absent for long stretches, for instance in 

stretch below Italian Bar, as far as mouth of North Fork. Still even 

in this stretch the slopes immediately adjacent to river bed are much 

steeper than higher up."
GEOMORPHOLOGY 27

Equally impassable is the inner gorge for a stretch 

of iy2 miles above Ross Creek, and again for a distance 

of 4 miles below the junction of the Middle and South 

Forks. In the last named stretch (fig. 15) the walls, 

though relatively low, are exceptionally sheer and close 

together. They grow rapidly higher toward the junction, where they measure 1,400 feet and are continued 

in the still higher walls of the gorges of the Middle 

and South Forks, which gorges are of essentially the 

same, sheer-walled type. Viewed from any of the 

high surrounding mountains, these gorges all seem like 

great mysterious moats dug by cyclopeaii hands deep 

in the granite floors of the broad mountain valleys. 

The extraordinary aspect of the junction is further 

enhanced by Balloon Dome, the solitary monumental 

dome of smooth, bare granite 600 feet in height, which 

rises from the upland spur between the two tributary 

gorges.

Although impressive as a scenic feature, the inner 

gorge of the San Joaquin River is far surpassed in 

depth and grandeur by the gorge of the Middle Fork. 

That gorge, with its smooth walls of exfoliating granite

FIGURE 15. View up gorge of the Sail Joaquin River toward Balloon 

Dome (altitude 0,900 feet), the great monolith which stands between the canyons of the Middle Fork and the South Fork at their 

juncture. The massive granitic rocks which here form the walls 

of the gorge are exfoliating in many places.

510207 60 3

3,UUO to 3,5l)0 feet in height, streaked with silvery ribboii cascades that glide clown from lofty hanging valleys, affords an unusually fine example of the massive 

type of cliff sculpture that finds its noblest expression 

in the Yosemite region. The gorge maintains its great 

depth and rugged grandeur for L5 miles, a distance of 

more than twice that of Yosemite Valley. As far as 

the vicinity of Fish Creek, it makes many turns that 

correspond to the crooked course of the river. Two to 

three miles broad from rim to rim, the gorge occupies 

practically the entire width of the canyon, there being 

little left of the outer mountain valley beyond its rims. 

Into it empty two great tributary gorges 2,000 to 2,500 

feet in depth, the gorges of the North Fork and Fish 

Creek, with the result that a climax of imposing canyon 

topography is seen that is surpassed in but few other 

parts of the Sierra Nevada.

Above the mouth of Fish Creek, the canyon of the 

Middle Fork makes a right angle turn, and immediately beyond, it undergoes a radical change in form 

and aspect. Its walls flare apart, and a longitudinally 

ridged rock floor, a mile wide, spreads out between 

them. There is still an inner gorge cut in this rock 

floor, but it is a relatively small, subordinate feature. 

Northward this gorge becomes shallow rapidly, and in 

about 4 miles it comes to a head, one half of a mile 

below Rainbow Falls. Thence upward the canyon 

assumes the form, essentially, of a simple glacier trough 

with broad level floor and parallel spurless sides. It 

maintains depths, below the flanking uplands, which 

decrease from 1,500 feet to 1,000 feet a short distance 

from its head. The latter divides, the east branch leading steeply up to the Agnew Pass, the west branch to 

the outlet of Thousand Island Lake.

In the midst of this broadly open part of the canyon, 

which with its charming meadows and stately pine 

groves is the very antithesis of the constricted, forbidding gorge below, is situated the Devils Postpile. This 

mass of columnar basalt forms a solitary hump in the 

canyon, about 300 feet high and elongated along the 

axis of the valley of Middle Fork. This hump is the 

first of several such obstructions. For several miles 

above Pumice Flat, the broad trough shape of the 

canyon is hardly evident to one traveling through its 

depths because of the succession of rock riclges, 300 to 

500 feet high, that occupy its floor. These ridges are 

composed not of basalt, but of metamorphic and granitic rocks. Between them are timbered flats and lush 

meadows, among which the Agnew Meadows are by 

far the largest.

Ln its upper course the canyon contracts to a V-shape, 

but otherwise it retains the aspect of a glacial canyon. 

Its sides are notably smooth, spurless, and parallel,
28 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

and 011 the west side a series of hanging valleys contaming rock-rimmed lakes and lakelets overlook the 

canyon at heights varying from 500 to 1,400 feet. This 

upper stretch of the canyon, which trends southeastward, parallel to the main divide of the Sierra Nevada, 

and the broadly trough-shaped stretch below, which has 

a southward trend, are both remarkable for their nearly 

straight courses. The river follows a sinuous path 

through the bottom, but the sides of the canyon in both 

of these stretches have but faint curvature, in contrast 

to the walls of the gorge belo\v the elbow-bend at Lion 

Point.

Two tributaries of the Middle Fork of the San 

Joaquiii River the North Fork and Fish Creek likewise have notable canyons. North Fork Canyon heads 

on the southeast face of Mount Lyell (13,090), at the 

extreme north end of the San Joaquin Basin, and between Electra Peak (12,462 feet) on the west and 

Mount Davis (12,308 feet) on the east. It extends 

southward along the west base of the great Hitter 

Range, though gradually diverging westward from it. 

North Fork Canyon is troughlike throughout, its wrest 

walls rising 1,500 to 2,500 feet to irregular, glaciated 

uplands, and its east walls, which are continuous with 

the slopes of the Ritter Range, rising to impressive 

heights of 5,000 feet or more in the Minarets and neighboring summits. The southerly course of the North 

Fork Canyon is zigzag, rather than direct, reflecting 

similar irregularities in its river, whose course has short 

southwestward sections alternating with longer southeastward ones. Glacial modification of North Fork 

Canyon is evident not only in its cross section, which 

is typically U-shaped, but also in the rounding of its 

many bends. The canyon is, therefore, better described 

as sinuous than as sharply angular. On the east, many 

short, straight tributaries descend steeply from the 

west slope of the Ritter Range; and on the west longer 

tributaries, with less steep gradients, enter the North 

Fork through prevailing southeastward courses.

Fish Creek Canyon, which trends northwestward for 

the most part, parallel to the adjacent main crest of 

the range, differs from the North Fork Canyon in being 

remarkably straight and spurless. Its floor lies 2,500 

to 3,000 feet below the glacially scoured uplands to the 

west, and 4,000 feet below high points on Mammoth 

Crest, to the east. The 3i£-mile section above its junction with Middle Fork is a steep-walled, narrow gorge; 

farther upstream, the canyon opens and becomes broadfloored, particularly beginning at the 7,800 foot level. 

In its upper part the valley has the aspect of a trough - 

like glaciated canyon, and its many small tributaries 

have scores of alpine lakes in their upper reaches and 

cirques.

The South Fork of the San Joaquin approaches its 

junction with the Middle Fork through a sheer-walled 

gorge that is even narrower than that of the Middle 

Fork and impassable so far as is known to the author. 

It attains a maximum depth of 2,200 feet opposite 

Balloon Dome and thence it shallows head ward very 

rapidly, so that in a distance of about 10 miles it is 

reduced to an insignificant trench a few hundred feet in 

depth (fig. 16). As a consequence, the gorge of the 

South Fork is not comparable in scenic grandeur to 

the gorge of the Middle Fork. It has instead the 

aspect of a mysterious cleft or abyss in whose depths 

the river is all but hidden from view.

The South Fork makes an extremely rapid descent 

in this gorge. It falls 2,300 feet in 12 miles that is, 

nearly 200 feet to the mile on an average. Actually the 

descent is largely concentrated in the lower third of the 

gorge, the fall there being 1,250 feet in 4 miles. The 

steepest stretch is but a short distance above the junction ; the stream there descends about 400 feet in 1 mile.

The head of the gorge is ill defined. About 14 miles 

above the junction, near the mouth of Rattlesnake 

Creek, the gorge is still 500 feet deep, and for several 

miles farther upstream it continues as a shallow furrow 

in the floor of the broad mountain valley of the South 

Fork. That mountain valley is, in comparison even 

with the deeper and wider parts of the gorge, of immense size. Throughout the first 12 miles above the 

j unction it is 4 to 5 miles wide, measured from the base 

of the mountains 011 one side to the base of the mountains on the other. It is not level floored, however. 

The bases of the mountains just referred to are 1,000 

feet above the edges of the central gorge. The flanking peaks on the south side rise 4,000 feet above the 

valley, those on the north side from 4.500 to 5,000 feet.

FIGUKE 16. View southeastward from end of ridge north of Hoffman 

Meadow, looking up the shallowing, upper section of the Pleistocene 

canyon of the South Fork of the San Joaquin River. On either side 

of the canyon are remnants of the broad Pliocene valley.
GEOMORPHOLOGY 29

The conditions along the South Fork are exactly the 

reverse from those along the Middle Fork. On the 

latter the inner gorge widens at the expense of the outer 

valley and attains imposing dimensions; on the South 

Fork the inner gorge dwindles to a mere furrow and 

the outer valley is the dominant feature.

Headwarcl the great mountain valley of the South 

Fork contracts by degrees, at the same time assuming 

more and more the form of a simple U-shaped glacial 

trough with parallel, spurless sides. However, its 

floor is level only in places, being obstructed at intervals, like the floor of the upper Middle Fork Canyon, 

by knobs and ridges of resistant rock. Such is the case 

notably above the junction of Mono Creek, where a 

ridge 600 feet high and a multitude of lesser ridges and 

knobs, all of granite, make a curiously broken topography, extremely rugged on a small scale and correspondingly difficult to traverse. The most conspicuous obstruction is a riclge of granite 1,000 feet high that separates Poison Meadow from Jackass Meadow. It is 

known as the Jackass Dike although it is not a dike 

at all in the geologic sense. This riclge stands directly 

in the axis of the valley, forcing the river to make an 

eastward detour. Of unusual interest is the ridge of 

smooth, almost flawless massive granite between 100 

and 200 feet high that projects squaigly across the 

valley floor just below Florence Lake,Jfeaving a small 

gateway through which the river can pass.

In the vicinity of Florence Lake the U -shape and the 

glacial aspect of the valley become pronounced and 

unmistakable. Upland shoulders develop 011 both sides, 

thereby delimiting the U-shape more sharply; and 

associated with these shoulders are many small hanging valleys nearly all of which contain typical glacial 

tarns. At the Blaney Meadows the U-shaped trough is 

still further accentuated by the presence of lateral 

moraines that extend like continuous embankments 

along the upland shoulders. These shoulders stand 

about 2,3uO feet above the valley floor, and the adjoining peaks rise 3,500 to 4,600 feet about it.

Above the Blaney Meadows the trough narrows, so 

that there is room for only a few strips of bottom land 

along the stream, making the term canyon more appropriate than the term valley. Each of the three 

head branches of the South Fork Canyon Goddarcl 

Canyon, Evolution Valley, and Piute Canyon is of 

the same general type. All are narrow troughs with 

smooth, spurless, parallel sides; and all have, like the 

upper course of the Middle Fork Canyon, nearly 

straight or at best gently curving courses. Sharp 

bends and strong windings such as characterize the 

main canyon of the San Joaquiii River are conspicuously absent from them.

510207 60 4

Goddard Canyon, which is the pathway of the main 

headwater branch of the South Fork, is the most 

nearly straight of the three. It maintains a depth of 

about 2,000 feet below the upland shoulders to within 

a mile of its head, where the floor rises abruptly to the 

level of the upland and terminates in .a beautiful 

amphitheater containing Martha Lake, a nearly circular lake three quarters of a mile in diameter. 

Throughout its extent, Goclclarcl Canyon is flanked by 

peaks that rise from 3,000 to 3,500 feet above its floor.

Evolution Valley, which hangs 600 feet above the 

main valley (fig. 17), is correspondingly less deep 

below its upland shoulders. These shoulders, moreover, are much broader than those of Goclclard Canyon 

 so broad that they constitute platforms from which 

the flanking peaks rise as separate entities, far removed 

from the central trough (fig. 20). As a result the 

valley as a whole has a widely open aspect which, together with the breadth of its floor and the presence of 

several natural meadows, justifies the appellation of 

"valley" rather than of "canyon," although the total 

depth below the flanking peaks is fully as great as that 

of Godclard Canyon.

Evolution Valley comes to a head abruptly in a small 

cirque to the east of the majestic peak named The 

Hermit; but this valley head does not mark the extreme 

limit of the hyclrographic basin of Evolution Creek. 

The basin extends 5 miles farther to the/southeast at a 

higher level, the true head being at^Mniir Pass, beyond 

which are the sources of the Middle Fork of the Kings 

River. Evolution Creek drops into the head of Evolution Valley by a spectacular s.cagitele 1,000 feet in 

height, It spills irom the lip of an upland valley of 

rare scenic beauty that contains a series of vividly 

colored, gemlike lakes, and is guarded by a group of 

imposing alpine peaks the Evolution group, which is 

dominated by Mount Darwin, 13,841 feet in altitude. 

This remarkable upland valley has come to be known 

as Evolution Basin (fig. 23). It is a noteworthy fact 

that, although it forms an upper story, so to speak, to 

Evolution Valley, and has its lip at an altitude of 

10,990 feet, it still lies 2,850 feet below the flat summit 

of Mount Darwin.

Piute Canyon differs from the two canyons just described mainly in that it splits into two forks extending 

almost at right angles to each other. Both forks, 

however, consist of typical smooth-sided and nearly 

straight troughs, flanked by broad upland shoulders. 

The northeast fork, known as French Canyon, heads 

in a shallow amphitheater below Pine Creek Pass; the 

southeast fork similarly heads in a shallow amphitheater below Piute Pass. These passes have altitudes 

of 11,000 and 11,400 feet respectively.
30 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

FIGURE 17. View from valley of the South Fork of the San .Toaquiii River looking eastward at the mouth of Evolution Valley, which hangs

GOO feet above the floor of the main valley. Photograph by G. K. Gilbert.

The uplands flanking these troughs attain remarkable breadth in some places and are covered by many 

lakes and tarns. No less than 9 good-sized lakes and 

12 small tarns lie on the upland to the east of French 

Canyon: 5 lakes and several tarns lie on the upland to 

the west of it, and 1 lake and several tarns lie at its 

head. The upland to the north of the southeast fork, 

which is known as Humphreys Basin, comprises 10 

square miles of area and contains a dozen lakes and 

many tarns. Its central feature is a lake over 1 mile 

in length, well named Desolation Lake.

Two other canyons are tributary to the South Fork, 

namely, the canyons of Bear Creek and Mono Creek. 

Both are essentially of the trough type and have distinctly U-shaped cross sections; both have upland 

shoulders in their lower courses, but are almost devoid 

of such features in their upper courses. Both are 

3,000 to 4,000 feet deep below the flanking peaks.

HANGING VALLEYS

In describing the San Joaquin Canyon and its main 

branches, cursory mention has been made of hanging 

valleys that debouch into the canyons. These hanging 

valleys are a characteristic feature of the basin, and, 

compared to the other basins of the west slope of the 

Sierra Nevada, they are unusually numerous. Indeed, 

so few of the lesser tributary valleys of the San 

Joaquin River and its main branches are continuously
GEOMORPHOLOGY 31

graded down to the level of the master stream throughout their length, that it may be said that hanging 

valleys are the rule rather than the exception. Though 

the basin lacks the many spectacular waterfalls that 

distinguish the Yosemite region, it does possess an 

array of cascades that pour from the mouths of the 

hanging valleys (figs. 18, 19).

Of special note is the fact that the hanging valleys 

are found not only in the glaciated upper course of 

the canyon but also throughout the unglaciated lower 

course in fact, into the foothills zone, within a few 

miles of the mouth of the canyon. Indeed, the hanging valleys are most numerous in this lower section, and 

here also are found some of the best preserved 

examples.

The hanging valleys are as a rule, of moderate depth, 

broad, and of gentle gradient that is, they are mature 

or even postmature in form. Several terminate abruptly at the brinks of the canyons, with lips as yet

FIGURE 18. Falls of Stevenson Creek on east side of San .loaquin 

Canyon. Exfoliation shells are evident in the massive granitic rock 

which holds up this hanging tributary valley.

FIGURE 19. Big Creek Cascade, viewed from vicinity of Cascada 

Station below Huntington Lake. Kerckhoff Dome (not labeled on 

topographic map) in background. Photograph by R. A. Parker.

scarcely notched, so that their waters tumble from 

them in spectacular cascades; others are trenched by 

incipient gulches for short distances from their mouths; 

still others are so trenched for distances of several 

miles, but even these have untrenched upper courses 

long enough to show unmistakably that they belong to 

a family of mature valleys graded to a former higher 

level of the master stream.

As became clear in the field, and is evident also from 

the topographic map, most of the hanging valleys 

appear to fall into two distinct sets, or tiers. Those of 

the lower set are associated with the benches and shoulders which flank the San Joaquin Canyon. Those of 

the upper set form part of the billowy topography of 

the upland surface.

The hanging valleys of the lower set are more 

numerous, and, generally speaking, are better preserved. Some are remarkably clean-cut, being as yet 

almost unnotched, and the waters that issue from them 

cascade and glide down the walls of the inner gorge still 

unrecessed. This is notably the case in the 6-mile sec-
32 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

tion of the San Joaquin Canyon above the mouth of 

Italian Creek, wherein the shoulders and benches are 

most strongly developed and the inner gorge is narrow 

and steep sided.

Though the hanging valleys of the lower set terminate above the canyon floors at different heights, they 

nevertheless vary within certain limits and according 

to a significant pattern. Their heights are least in 

the foothills and increase upstream, as the following 

examples show. The valley of Fine Gold Creek has a 

profile showing a discordance, with reference to the 

floor of San Joaquin Canyon, of about 400 feet; Big 

Sandy Creek, 7 miles farther upstream, has a somewhat greater discordance. About 15 miles above the 

mouth of Big Sandy Creek, Backbone Creek and Bald 

Mill Creek hang about 1,100 and 1,200 feet respectively. 

Still farther upstream are several valleys, mostly on 

the west side, clearly related to the flanking benches 

and shoulders of the canyon, which hang above the 

canyon floor at closely accordant heights ranging, for 

the most part, from 1,400 to 1,700 feet, generally close 

to 1,600 feet. Representative of this group are the 

hanging valleys of Saginaw Creek, Italian Creek, 

Hookers Creek, Clearwater Creek, Ross Creek, Fish 

Creek, and Shakeflat Creek. Shakeflat Creek is just 

within the glaciated area.

Big Creek, in leaving the upland at Huntington 

Lake at close to 7,000 fpet, descends steeply about 4,850 

feet through narrow Big Creek Canyon to reach the 

San Joaquin River (fig. 19). Its branch, Pitman 

Creek-Tamarack Creek, similarly leaves a broad open 

valley on the uplands south of Chinese Peak at about 

7,000 feet, and descends about 4,900 feet to the San 

Joaquin River. These hanging valleys are representative of the upper tier.

In the lower, unglaciated section of the San Joaquin 

Canyon a few streams are noteworthy in that they first 

cascade from lofty upland valleys into the outer canyon 

of the San Joaquin River, and then, some 2,000 feet 

lower, they plunge abruptly from a well-defined bench 

into the narrow inner gorge. These streams are hanging with reference to both the upland and the flanking 

t>enches. The most conspicuous example is Stevenson 

Creek, which descends in a brawling cascade from a 

foroad, shallow upland valley lying at about 5,100 feet, 

now partly drowned by Shaver Lake; and then, from 

a bench at about 3,400 feet, il makes a second descent, 

with a steep drop of about 1,600 feet, into the inner 

gorge of the San Joaquin River (fig. 18). The situation in the case of Jose Creek is somewhat similar.' 

Four branches of this stream (the longest ones heading 

about a mile above Ockenden) cascade from shallow

vales on the gently undulating plateau known locally 

as Pine Ridge, leaving its edge at an altitude of about 

5,400 feet; and then, after uniting into a single stream 

and flowing several miles on a relatively gentle gradient, at an altitude of 2,900 feet the waters again cascade 

wildly from the lip of the Jose Basin, making a descent 

of about 1,500 feet to the bottom of the inner gorge.

Farther up the San Joaquin Canyon, within the 

outermost glaciated section, where flanking benches 

and shoulders are feebly represented or lacking, most 

of the hanging valleys are part of the upland surface 

and therefore are referable to the upper set. Such is 

the case with the valleys of both Rock Creek and Jackass Creek. The latter, for example, leaves a mature 

valley on the uplands and descends steeply about 2,900 

feet to join the San Joaquin River.

Along the Middle Fork are numerous hanging valleys, most of which also belong to the upper set. Granite Creek tumbles into the Middle Fork from the fairly 

clean-cut lip of a hanging valley about 2,400 feet high. 

Stairway Creek, like Stevenson and Jose Creeks, has 

headwaters that descend steeply from upland valleys, 

and in its lower course it leaps from the unnotched 

lip of a hanging valley about 1,900 feet high. Directly 

opposite Stairway Creek, a streamlet cascades down 

about 2,300 feet from the brow of Junction Bluffs; and 

east of Lion Point another streamlet makes a precipitous descent of 2,600 feet from the edge of the upland. 

Crater Creek leaves its shallow upland valley at 8,600 

feet and makes a steep descent of 2,600 feet to join 

the Middle Fork; the last 700 feet of this descent is 

made as it drops into the head of the inner gorge. 

Farther up the Middle Fork, the height of the hanging 

valleys decreases by degrees, as the upper valley becomes shallower. Shadow Creek makes a descent of 

only 500 feet, and the streamlet that issues from Garnet 

Lake drops only 600 feet.

In the lower South Fork one finds only .a few hanging valleys of notable height. The streamlet which 

drains Cow Meadow hangs over 2,000 feet; Hoffman 

Creek falls about 1,800 feet from its upland vale; and 

Rube Creek makes a plunge of 1,500 feet. Farther up, 

the discordances diminish rapidly as the South Fork 

gorge shallows headward. Four Forks Creek and Rock 

Creek first cascade from upland valleys, and then in 

their lower courses they descend steeply about 1,000 

feet to join the South Fork. A few miles farther 

upstream, Rattlesnake Creek cascades from a valley 

only 500 feet high. Beyond this point new forms of 

topography appear; the broad upper valley of the 

South Fork, as it gradually contracts to a U-shaped 

glacial trough, possesses a set of lofty hanging side 

valleys.
GEOMORPHOLOGY 33

INTERCANYON UPLANDS

The great canyons of the San Joaquin River and 

its main branches are deeply trenched in the plateaulike uplands distinctive of the basin. These uplands 

are extensive in the central part of the basin, which in 

this respect is typical of the middle slope of the Sierra 

farther north. The uplands that flank the Yosemite 

Valley on both sides are of this general type, and so are 

the uplands on both sides of the Hetch Hetchy Valley 

and adjoining stretches of the Tuolumne Canyon. 

Liiidgreri (1911, p. 37-38) has noted the prevailingly 

plateaulike character of the middle slope still farther 

north in the range. In the southern Sierra Nevada, 

also, in the drainage basins of the Kings, Kaweah, and 

Kern. Rivers, there are similar areas on the middle 

slope.

In the San Joaquin Basin, the uplands form extensive plateaulike areas, commonly several miles wide, 

mostly at altitudes of 7,000 to 8,000 feet and having 

an aggregate area of about 100 square miles. They 

are readily traced westward and decline in altitude to 

5,000 or even 4,000 feet at their western margins within 

a few miles of the foothills, where they break off in 

declivities of 2,000 feet or more. Traced eastward, the 

uplands become higher and, for the most part, smaller 

and less continuous. Nevertheless they are recognizable as distinctive benches, shoulders, and other 

areas of undulatory surface which extend to the base 

of the High Sierra crests, at altitudes of 9,OUO feet or 

higher.

Where most typical, as on the middle and lower 

slopes of the Sierra, the uplands are not strictly flat, 

but undulating, with a relief generally less than 500 

feet and only exceptionally 1,000 feet. The valleys 

on the upland, where transected by the canyons of the 

San Joaquin River and its branches, are abruptly cut 

off and left hanging, or descend with greatly steepened 

gradient, as described in the foregoing section. The 

uplands bear many broad, grassy meadows (figs. 47,48), 

which from their topographic, situation and considerable extent obviously belong in a different category 

from the generally more restricted meadows which in 

places occupy the canyon floors (fig. 44).

The somewhat monotonous aspect of the uplands, 

resulting from the approximate concordance of their 

billowy timbered ridges, is relieved by scattered eminences that stand above their general level. These include isolated knobs and mountain groups, a few hundred feet high, common in the central part of the basin, 

and lofty ridges actually mountain ranges several 

thousand feet high especially characteristic of the 

upper part of the basin.

Some representative upland areas will be described 

its main branches are deeply trenched in the plateauof the San Joaquin Basin. Uplands slope southward 

and southeastward from the Chiquito Ridge and 

Kaiser Ridge and have hills and scattered knobs 

which range from a few hundred feet to as much as 

1,000 feet in height. These eminences have no definite 

trend, but many of the shallow upland valleys parallel 

the crests of the High Sierra. The uplands in this section, as well as elsewhere in the basin, have many bright 

green meadows in some of the broadly open valleys, 

interrupting the somber green mantle of coniferous 

forests that otherwise extends uniformly over the entire area. It is noteworthy that most of the uplands 

in this area were never overridden and modified by ice, 

even in the more extensive earlier glacial stage. (See 

glacial map, pi. 1.)

The lower San Joaquin Canyon, which bisects this 

area from northeast to southwest, separates the uplands 

adjoining Chiquito Ridge from those adjoining Kaiser 

Ridge. The uplands west of the canyon begin, at the 

base of Chiquito Ridge, at about 7,000 feet, and extend 

south westward 5 to 10 miles; then, at 5,500 feet, they 

terminate in an abrupt escarpment 1,500 to over 2,500 

feet- high. This escarpment, named South Fork Bluffs 

at the north, runs south-southeastward in a remarkably 

straight line as far as the San Joaquin River.

The uplands east of the canyon slope southwestward 

from altitudes of more than 9,000 feet at the head of 

Big Creek, to 4,500 feet on Bald Mountain, northeast 

of Big Sandy Valley. They thus decline 4,500 feet in 

a distance of 25 miles, or at a mean rate of ISO feet to 

the mile. South ward and southeastward the plateau 

country extends without significant break into the 

drainage basin of the Kings River.

Particularly noteworthy is the fact that the upland 

on Bald Mountain reaches within a few miles of the 

foothills, where it breaks off first in slopes of moderate 

declivity, then in a precipitous escarpment known as 

the Big Sandy Bluffs, the total drop being between 

2,000 and 2,500 feet. It is up through a recess in this 

escarpment that the celebrated "tollhouse grade" of the 

road from Tollhouse to Shaver Lake reaches the upland. To the southeast of the tollhouse grade the 

escarpment is continued by the steep front of the flattopped ridge known as Burro (Burrough) Mountain. 

The general trend of the escarpment is southeastward, 

and associated with it is a linear riclge, named Backbone Mountain, that trends in approximately the same 

direction.

North and northeast of Chiquito Ridge are other upland areas of essentially similar configuration, lying, 

for the most part, at altitudes of 6,000 to more than
34 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQU1N BASIN, CALIFORNIA

7,000 feet. Such are the Beasore and Mugler Meadows, 

in the headwaters of Chiquito Creek; and the various 

meadows in the area drained by the middle courses of 

Jackass Creek and Granite Creek. In the basin of 

Jackass Creek, where the many natural meadows afford 

summer pasturage for large herds of cattle, resistant 

rocks form residual knobs such as Jackass Rock, Squaw 

Dome, and Cattle Mountain, which stand 600 to 900 

feet above the undulatory upland (fig. 6).

Another upland tract occupies the triangle isolated 

by Kaiser Ridge on the south, the San Joaquin Canyon 

on the northwest, and the South Fork Canyon on the 

northeast. It slopes from a maximum altitude of 7,500 

feet along the northeast edge to about 6,000 feel at the 

southwest corner. This tract includes Cow Meadow 

and Hoffman Meadow, and from it rises Mount Tom, 

almost 2,000 feet high.

Farther to the north and northeast, upland tracts 

border the North Fork Canyon and, especially, the 

Middle Fork Canyon. For example, on the southeast 

side of Middle Fork Canyon a billowy tract at 7,500 to 

9,000 feet extends southward from Junction Bluffs. 

Across the canyon, a similar tract slopes southward 

from 9,000 feet at the Granite Stairway to 8,500 feet 

at Lion Point. Also, there is a significant upland 

stretching, with undulatory surface, from 8,700 feet at 

the north edge of Fish Valley to more than 9,000 feet 

at the base of Mammoth Crest and Mammoth Mountain. Both Mammoth Pass, altitude 9,300 feet, and 

Minaret Pass, altitude 9,200 feet, are at the general 

level of this upland surface and form part of it.

Other upland tracts are found in the areas drained 

by the South Fork and its tributaries. Those within 

the arc formed by the South Fork and Mono Creek 

include Onion Spring Meadow, Warm Creek Meadow, 

and other meadows lying, for the most part, at 7,000 to 

8,000 feet. Along the principal valleys tributary to 

the South Fork, remnants of the upland surface form 

marginal benches and shoulders. In some places, as 

along Mono Creek Canyon and Evolution Valley, these 

features are remarkably regular and continuous (figs. 

20, 21). In most places they undoubtedly have been 

more or less modified by glacial erosion. At the headwaters of Big Creek, in the Black Mountains-Hot 

Springs Pass area, upland tracts give rise to a number 

of extensive meadows, such as Long Meadow (figs. 47, 

48) and Rock Meadow.

Finally it should be noted that many of the valley 

heads at 9,000 feet or higher that indent the mountain 

ridges of the High Sierra are probably the erosioiial 

equivalents of the upland surfaces so extensively and 

well preserved at lower altitudes. This is indicated by 

their appropriate situation, altitude, and configuration,

FIGURE 20. View down Evolution Valley from high rock sill west of 

Evolution Lake. Fpland benches, remnants of the Miocene erosion 

surface, extend almost continuously along both sides of the U-shaped 

trough, which is a Pliocene valley modified by glaciation.

and is evident despite the fact that they have been 

resculptured in varying degrees into capacious, flatfloored cirques through intense and repeated glacial 

erosion. In this category may be placed the cirque 

basin of Thousand Island Lake (altitude 9,850 feet) 

at the head of the South Fork (fig. 38), the uppermost reaches of Fish Valley (the 5-mile section lying 

above 9,000 feet), and Evolution Basin (the 6-mile 

stretch above 11,000 feet, leading to Muir Pass), and 

probably many other cirques such as the Pioneer Basin 

at the head of Mono Creek and the expansive Humphreys Basin between the forks of Piute Creek.

LONGITUDINAL AND TRANSVERSE CRESTS

It might be anticipated that on the back slope of 

a tilted block range like the Sierra Nevada, furrowed 

as it is by deep transverse canyons, one would find a 

preponderance of transverse crests. Yet in the higher 

parts of the San Joaquin Basin, as also in those of the 

Tuolumne and Merced basins and many other sections 

of the Sierra Nevada, subsidiary crests trending northwest-southeast, parallel to the axis of the range, 

greatly predominate. Indeed, such longitudinal crests 

are characteristic, features of the upper part of the 

range, adding greatly, by their bold sculpture, to the 

scenic beauty of that alpine region, which has come to 

be known as the High Sierra. But nowhere in the 

range are longitudinal crests more numerous, more 

continuous, and more closely spaced than in the upper 

part of the San Joaquin Basin. Rising 2,000 to 3,000 

feet above the plateaulike uplands, and 4,000 to 5,000 

feet above the floors of adjacent canyons, they stand 

high enough to be considered mountain ranges. A 

number of the crests, as will be noted below, do not lie 

entirely within the San Joaquin Basin, but extend far
GEOMORPHOLOGY 35

FIGURE 21. Well-preserved bench, a remnant of the Miocene erosion 

surface, on the south side of Evolution Valley. The cascade descends 

from the mouth of a hanging valley.

beyond its limits. The presence of the longitudinal 

crests accounts also for the preponderance of longitudinal stream courses among the tributaries of the San 

Joaquin River.

One of the most noteworthy of the longitudinal crests 

is the Kilter Range in the northern part of the San 

Joaquin Basin. Its summits range from 11,000 to 

over 13,000 feet in altitude, including Mount Lyell 

(13,090 feet), Banner Peak (12,957 feet), Mount Bitter 

(13,156 feet), and the Minarets, that imposing group 

of summits which California!! mountaineers have aptly 

styled "the king and queen of the Sierras 7 and their 

retinue/' The Kilter Kaiige, exceptional in that it 

greatly overtops the drainage divide of the Sierra 

Nevada, about 6 miles to the east (see fig. 4), extends 

from Mount Lyell on the northwest to Iron Mountain 

on the southeast, a distance of 12 miles; but as will 

be clear from the topographic map, it is continuous 

northwestward with the Cathedral Range, which divides the upper Merced and Tuolumne Basins and 

which is also 12 miles in length. The two ranges, 

therefore, form a continuous crest whose aggregate 

length is 24 miles.

The Glacier Divide (fig. 22), in the southeast part 

of the San Joaquin Basin, is appropriately named 

for the many small ice bodies that cling to its shady 

and precipitous northeast flank. It is only 6 miles 

long, but as will be evident from the topographic map, 

it forms a northwestward extension of the sinuous 

crest that constitutes the main divide of the Sierra 

Nevada at the head of Evolution Creek (fig. 23). This

7 The popular use of the plural form Sierras, though it may seem 

inconsistent with the singular form of the name Sierra Nevada and 

High Sierra, is nevertheless fully justified by the multiplicity of 

serrate crests in the higher parts of the range. The term Sierra 

Nevada Mountains, on the other hand, is not tolerated in California, 

it being manifestly tautological.

FIGURE 22. View southeastward along Glacier Divide, showing marked 

asymmetry of Crestline resulting from more intense glaciation on 

the northerly slopes of this ridge. The northerly slopes bear & 

number of small glaciers, two of which show in this view.

crest continues southeastward far beyond the limits of 

the San Joaquin Basin and, as may be seen 011 the 

Bishop and Mount Whitney quadrangles, extends without significant break around the heads of the Kings 

and Kern Rivers. It has a total length, including the 

Glacier Divide, of 76 miles, and bears no less than 

90 peaks ranging from 12,000 to over 14,000 feet in 

altitude, including Mount Whitney (14,496 feet), the 

culminating summit of the Sierra Nevada.

Noteworthy also is a series of aliiiecl crests farther 

to the west, whose principal units within the San 

Joaquin Basin are Chiquito Kidge, Kaiser Ridge, and 

the LeConte Divide.

Chiquito Riclge (fig. 8) is the crest lying west of the 

San Joaquin Canyon. It controls the southeastward 

courses of Chiquito Creek and its West Fork. This 

riclge, more than 10 miles in length, trends northwestward to the border of the San Joaquin Basin and continues within the Merced Basin as far as Mount 

Raymond, on whose west spur stands the Mariposa 

Grove of Big Trees. Its total length, thus measured, 

is 14 miles. Its summits rise a little above 8,000 feet 

in altitude, yet they stand 3,000 to 4,000 feet above the 

valleys of Chiquito Creek and its West Fork.

South of the San Joaquin Canyon is Kaiser Ridge, 

the great crest that controls the course of the South 

Fork of the San Joaquin River and walls off the 

High Sierra portion of the basin. A western segment 

of Kaiser Riclge (termed Kaiser Crest on some maps) 

rises to the north of Huntington Lake (fig. 24). Another segment continues the crest to the east of Kaiser 

Pass. Together the two segments form an arcuate 

ridge 19 miles long, bearing first toward the east, then 

east-southeast, and finally south toward the Hot 

Spring Pass. The principal summits on this divide
36 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA
GEOMORPHOLOGY 37

exceed 10,000 feet in altitude and stand 4,000 feet 

above the valley of the South Fork.

From Hot Spring Pass, a sinuous mountain rampart 

runs eastward with increasing elevations to Mount 

Henry (altitude 12,197 feet), where it joins the 

LeConte Divide. The latter, a spectacular crest bearing a row of 12,000-foot peaks, extends in a straight 

line 9 miles southeastward to Mount Reinstein (altitude 12,595 feet), at the extreme southeastern corner 

of the basin. The crest continues southeastward 8 

miles farther, into the Kings River Basin, where it is 

known as the White ] >ivide.

This succession of crests, from Mount Raymond at 

the north to the south end of the White Divide, has 

an overall length of more than 60 miles, and twothirds of this length lies athwart the San Joaquin

FIGURE 24. View southeast across Twin L,a' es. The cirque wall in the 

background is cut into Kaiser Ridge, only the north side of which 

was effectively eroded by the ice in the later glaciation. The near 

shore and the low cliffs on the right are composed of white crystalline limestone; the island and the far shore are composed of 

granite.

Basin. Though the line of crests shows many irregularities of trend, as might be expected in vie\v of its 

great length, the northwestern direction nevertheless 

predominates.

There are other northwestward-trending crests hi the 

San Joaquhi Basin, but none are comparable in length 

and continuity to those described. A nameless crest 

between the South Fork of Bear Creek and the South 

Fork of the San Joaquin River, bearing Mount Seiiger 

and Mount Hooper, is 9 miles long. Another nameless 

crest between Goddard Canyon and Evolution Creek, 

bearing Mount McGee (fig. 25) and Emerald Peak, is 

only 6 miles long, but if its continuation in the Kings 

River Basin, here called the Black Divide, be added to 

this length the entire length is 15 miles. About 10 

miles southwest of the Bitter Range is a crest bearing 

Maclera, Gale, and Sing Peaks; and northwestward

510207 60 5

FIGURE 25. Section of a High Sierra crest: the Mount McGee group 

of summits and the cirques at the head of McGee Creek, viewed 

from a point south of Evolution Valley.

from Triple Divide Peak, where it enters the Merced 

Basin, this crest is continued in the much more impressive Clark Range. The over-all length of this crest is 

also about 15 miles.

As compared with the prominent and persistent 

longitudinal ridges which have been described, the 

transverse crests are not only fewer but of subordinate 

importance in the configuration of the San Joaquin 

Basin. One of thece. the Goddard Divide (fig. 26), 

follows part of the southeast edge of the basin, where 

it separates the headwaters of the South Fork of the 

San Joaquin River from those of the Middle Fork of 

the Kings River. From Mount Wallace on the mam 

Sierra crest, this divide trends southwestward to Mount 

Reiiisteiii on the LeConte Divide, linking the two 

crests, which here are only 7 miles apart. Noteworthy 

features of the Goddard Divide are Mount Goddard 

(altitude 13,555 feet) and Muir Pass, by which the 

John Muir Trail enters the basin of the Middle Fork

FIGURE 26. View from base of Red Mountain, looking up Goddard 

Canyon to Goddard Divide and, at left. Mount Goddard (altitude 

i:{,555 feet). Photograph by G. K. Gilbert.
GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

of the Kings River. At the north edge of the San 

Joaquin Basin, a nameless transverse crest straggles 

along the 11-mile interval between Mount Lyell and 

Triple Divide Peak, separating the headwaters of the 

North Fork of the San Joaquin Basin from those of the 

Merced Basin.

A few minor crests form curves or hooks. The most 

prominent examples are the Silver Divide, about 10 

miles long, and the Mono Divide, 7 miles long, both in 

the High Sierra region between the South and Middle 

Forks. Both branch off from the main Sierra crest in 

southwestern directions but gradually curve around to 

the northwest.

TABULAR SUMMITS

Most ridges in the High Sierra part of the San 

Joaquin Basin have splintered crests or sharp summits 

due to the widening of adjacent valleys and the enlargement of cirques by glacial action. However, 

there are at least two summits in this basin which, like 

a number of other peaks in parts of the Sierra Nevada 

(Matthes, l»33a, p. 34-35; 1933c; 1937a, p. 8-9) have 

tabular summits. These peaks, Mount Darwin and 

Mount Wallace (fig. 27), are both on the main crest of 

the range, near the southeast corner of the basin. 

Mount Darwin has two detached summit platforms, 

13,841 feet and 13,701 feet in altitude, respectively, 

which stand nearly 3,000 feet aboA<e the level of the 

adjacent Evolution Basin. Mount Wallace has a summit platform at an altitude of 13,328 feet.

These tabular summits were preserved because the 

preglacial Mount Darwin and Mount Wallace were 

full-bodied mountains, broad enough so that though 

trimmed back by the erosional effects of glaciers headFIGIRE 27. View from John Muir Trail in Evolution Basin : Mount 

Darwin at left, Mount Wallace at right. These two mountains have 

nearly level summits that are remnants of an ancient erosion surface. 

The level to which the ice rose in Evolution Basin is indicated by 

the upper limit of corrasion. Above this level the cliffs are deeply 

riven by frost and gullied by snow avalanches.

ing on their slopes they nevertheless wrere not reduced to attenuated points, like the neighboring peaks. 

The flat summits that remain, appear to have escaped 

glaciation altogether and exhibit only the smoothing 

effect of long-continued nivation and concomitant 

solifluotioii.8

MAIN DRAINAGE DIVIDE

The main drainage divide of the Sierra Nevada at 

the head of the San Joaquin Basin is of unusual 

interest. It does not follow the same northwestern 

crest throughout its length, but is in places offset 

abruptly from one crest to another. Thus at the Piute 

Pass the divide is offset sharply northeastward to the 

crest which bears Mount Humphreys. Six miles farther, at the northwestern end of that crest, the divide 

again is sharply offset to the southwest, across the Pine 

Creek Pass. Thence the divide pursues a winding 

course along alternate northwestern and northeastern 

crests, as far as Mount Stanford, at the head of Mono 

Creek. There it turns abruptly southwestward along 

the crest which, farther to the southwest, bears the 

name Silver Divide. At Red and White Mountain, it 

finally resumes a northwestAvard course, and this it 

maintains for a distance of 27 miles to AgneAY Pass at 

the northern corner of the San Joaquin Basin. The 

divide makes many minor turns and Avindings, especially in the stretch southeast of the Mammoth Pass, 

but these are due largely to deeply inset glacial cirques.

Throughout the greater part of its extent, the divide 

at the head of the San Joaquin Basin has a strongly 

serrate skyline marked by a long succession of jaggecl 

peaks. Even the Piute and Pine Creek Passes are 

scarcely deep enough to mar the general saAvtooth 

effect. But at the Mammoth Pass, the divide abruptly 

loses its spectacular aspect and, dipping from altitudes 

of over 11,000 feet to a level of 9,300 feet, assumes a 

subdued and relatively monotonous appearance. Mammoth Mountain, it is true, again lifts the diAride for a 

space above the 11,000-foot level, but beyond that 

mountain the divide again sags to about 9,200 feet in 

the IOAV Minaret Pass. From this long sag it ascends 

by gentle slopes to the crest of the relatively smooth 

ridge that culminates in San Joaquin Mountain and 

terminates at the Agiiew Pass.

8 These summits apparently were not visited by Matthes. They are 

probably very similar to the summit of Mount AVhitney, which Matthes 

has described in detail (1937a. p. 16-18; 19501), p. 88-89).

Just outside the San Joaquin Basin is another summit which may 

belong to the same category as Mount Wallace and Mount Darwin. 

This summit, not labeled on the topographic map, has been designated 

"Mono Mesa" by J. T. Howell, and is a granitic tableland with an 

altitude of 12,240 feet, located at the head of Mono Creek, 1 mile 

east of the intersection of Fresno, Mono, and Inyo Counties. Howell 

suggests that "it represents what is probably California's oldest land 

surface that is unaltered by erosion."
GEOMORPHOLOGY 39

Opposite the low sag at the Minaret Pass the valley 

lands to the east of the Sierra Nevada attain an 

unusually high level about 8,000 feet above the sea 

and as a consequence the eastern escarpment, which at 

Mount Humphreys stands 9,500 feet high, here 

dwindles to a mere 1,200 feet. The escarpment, in 

this its lowest stretch, is masked by great accumulations of pumice derived from nearby volcanoes, and so 

presents only an unimpressive slope of moderate declivity. As if to dwarf it completely into insignificance, 

the sky piercing summits of the Ritter Range (fig. 4) 

rise a few miles to the west.

RELATION OF MAIN DRAINAGE DIVIDE TO ESCARPMENT ON 

EAST SIDE OF RANGE

It is commonly stated, in brief generalized sketches 

of the Sierra Nevada, that the range consists essentially of one great crustal block tilted toward the 

southwest, with its northeastern edge elevated so as to 

form the crestline. That statement, which implies 

that the crestline, or main drainage divide, coincides 

with the top of the great east escarpment, is literally 

true for some parts of the range, but it does not hold 

good for many other parts, notably the part here under 

consideration.

To any one who traces in detail on the topographic 

map the course of the main drainage divide, or crestline, of the range around the headwaters of the San 

Joaquin River, it must be evident that as a geomorphic 

feature it is distinct and essentially independent from 

the escarpment. In some places the main divide lies 

many miles to the southwest of the escarpment. Indeed, throughout its total length of 70 miles at the 

head of the San Joaquin Basin the divide coincides 

with the top of the escarpment only in two short 

stretches: in the 3-mile section between Mount Humphreys and Mount Emerson, and on the top of Mammoth Mountain.

From the crest between Mount Humphreys and 

Mount Emerson the escarpment falls off steeply 5,000 

feet to what is known as the Buttermilk Country. The 

Buttermilk Country is still between 3,000 and 4,500 

feet above Owens Valley and separated from the latter 

by several miles of the jumbled Tungsten Hills; but 

these hills are only details of the much-faulted and 

fractured front of the range, and the fact remains that 

the main escarpment of undisturbed rock rises directly 

from the Buttermilk Country. Near Mount Emerson 

southward, the escarpment is abruptly offset 12 miles 

northeastward, and as a consequence to the southeast 

of Bishop Creek, a large triangular area of upland 

country intervenes between escarpment and main 

divide. It is thus evident that in this section the

main drainage divide of the range is in no wise determined by the top of the escarpment, but is an ancient 

erosioiial divide that antedates the creation of the 

escarpment by tectonic movements.

Northward from Mount Humphreys, the main 

divide and the escarpment diverge. Basin Mountain 

and Mount Tom, which presumably indicate approximately the original brink of the escarpment, stand l1/^ 

and 3 miles respectively to the northeast of the divide, 

attached to it by spurs that bear remnants of an 

unbroken surface corresponding in general altitude 

with the upland to the west of the divide. North of 

the canyon of Pine Creek, moreover, the distance between divide and escarpment increases abruptly, and 

another large upland area intervenes between them. 

This upland area attains a maximum breadth of 6 miles 

at the point where the escarpment makes a right-angle 

turn, from north-northeast to west-northwest. The 

configuration of the upland area is, like that of the 

upland to the southeast of Bishop Creek, essentially 

analogous to that of the High Sierra portion of the 

San Joaquin Basin, except that it drains northeastward instead of southwestward. The upland area 

just mentioned narrows westward and tapers to a point 

on Mammoth Mountain. Thence to the Agnew Pass 

the divide remains close to the top of the escarpment 

but it nevertheless does not coincide with the latter, 

being separated from it throughout by a narrow strip 

of gently sloping upland.

At Agnew Pass, the main divide finally deviates 

widely from the generally northwestward course of the 

main escarpment. It swings westward and southwestward to the Ritter Range, follows that range from 

Mount Davis to Mount Lyell, and returns to the escarpment by a northeasterly course, thus making a detour 

around the head of the Rush Creek Basin, which drains 

into Mono Lake. The maximum departure of the 

main divide from the escarpment, on Mount Lyell, is 

8 miles. The Rush Creek Basin is not merely a canyon 

with branching headwater gulches cut into the escarpment, but an upland area of High Sierra aspect, and 

its central valley, though cut to considerable depth, 

hangs 1,800 feet above the foot of the escarpment at 

Reversed Creek.

From these facts it is clear that at the head of the 

San Joaquin Basin the main drainage divide of the 

Sierra Nevada bears 110 constant relation to the east 

escarpment of the range, but is, except at two points, an 

independent feature and one of wholly different origin.

The geomorphologic features of the San Joaquin 

Basin closely resemble in their broad relationships
40 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQTJIN BASIN, CALIFORNIA

those of the neighboring Yosemite region. However, 

as previously noted, they are distinguished by relative 

simplicity, being singularly free of those conditions 

which make Yosemite a special case and which complicate the records of other basins.

Briefly, the salient features may be summarized as 

follows: The San Joaquin Canyon is essentially a narrow, youthful gorge cut into the floor of a relatively 

broad, mature valley. This in turn is flanked by extensive undulating uplands surmounted by knobs and 

mountainous crests. At least one crest has peaks that 

bear distinctively tabular summits.

It is evident that these features are the products of 

four partial cycles of stream erosion, each initiated by 

a major uplift. At higher levels, erosional records 

have been obscured, as a result of repeated glaciation. 

The erosional records will be analyzed first, and in the 

next chapter the superimposed effects of glacial action 

will be considered. In general, it will be found advantageous in the present analysis, to work from the 

youngest to the oldest features of the landscape, and so 

far as possible to begin with the unglaciated lower part 

of the range, thence discussing the glacially modified 

higher parts to the east.

EROSION SURFACES

Expressive of the latest partial cycle of stream erosion are the narrow, V-shaped gorge or "inner canyon1 ' 

of the San Joaquin River and its branches. These 

features are regarded as being entirely of Pleistocene 

origin. The youthfulness of the gorge, as shown by 

its narrow -shape and the steepness of its cliffy sides, 

is evident, and the fact that it is still being deepened 

and extended headward clearly shows that enough time 

has not elapsed since the last uplift took place to enable 

the stream to intrench itself deeply all the way to its 

sources. At the same time there are ample indications 

that most of the gorge cutting was done prior to the 

great extension of the El Portal glaciers. On the basis 

of these relationships, the Pleistocene gorge of the San 

Joaquin Canyon may be correlated with the "canyon 

stage" of the Yosemite region.

The benches and shoulders which flank the Pleistocene gorge in the lower and middle reaches of the basin, 

giving the San Joaquin Canyon a "two storied1 ' aspect 

by reason of the "outer valley" which they produce, 

are remnants of a mature valley developed in a partial 

cycle of erosion that preceded the canyon stage. These 

remnants are best preserved in the 6-mile section between the mouth of Italian Creek and the mouth of 

Big Creek; farther upstream they are less continuous 

and distinct but nevertheless traceable; and in the

main branches of the San Joaquin, above the heads of 

the gorges, they are continued by the actual upper 

valleys themselves, here untrenched by streams but 

glacially deepened and remodeled to a greater or less 

extent into U-shaped troughs. The maturity of these 

valleys is indicated by their broadly flaring cross sections and their low, smooth gradients (deduced, in 

the case of the San Joaquin Canyon itself, from the 

extended gradients of the lateral valleys that were left 

hanging in the latest cycle of erosion). Evidently in 

this partial cycle of erosion the San Joaquin River 

extended its main branch valleys much farther headward than it has in the present (canyon) cycle in 

fact almost to the crest of the range. The head of 

Middle Fork valley, for example, probably was then 

about 3 miles above Agnew Meadows; that of the 

South Fork at about the position of the present head 

of Evolution Valley. The maximum depth of the San 

Joaquin valley at this stage was in the vicinity of the 

mouth of Stevenson Creek, where it was cut about 1,800 

feet below the uplands.

To have attained its mature character the valley 

must have required, considering the durable character 

of the rocks in which it was produced, a period several times and probably not less than five times as 

long as that which was required for the carving of the 

Pleistocene gorge. It may be inferred that the partial 

cycle of erosion in which the valley was developed embraced all, or nearly all, of the Pliocene epoch. Accordingly, the Pliocene valley of the San Joaquin 

River may be assigned to the "mountain valley stage" 

of the Yosemite region.

The undulating uplands into which the Pliocene valleys have been cut are erosion surfaces referable to a 

still earlier cycle. Remnants of this surface are extensive and well preserved, in spite of their antiquity, 

because they are developed on the prevailingly massive, 

and therefore obdurate, granitic rocks which underlie 

a great part of the basin. The remnants clearly indicate that the landscape produced in this cycle was one 

of late mature aspect, with a relief over wide areas of 

less than 1,000 feet. Locally, however, monadnocks 

not only scattered hills and mountain groups but even 

ranges a dozen to a score of miles long, most of them 

trending in a northwestern direction give it much 

greater relief, for example 1,500 feet in the vicinity 

of Shaver Lake and over 2,500 feet at the present crest 

of the Sierra Nevada.

In the High Sierra region, the uplands reached to 

the base of the monadnock ranges and occupied the 

intervals between them. The head of Middle Fork 

valley lay essentially where it now does, in the position of Thousand Island Lake; that of the South Fork
GEOMORPHOLOGY 41

valley, in Evolution Basin; and other principal valleys 

headed in comparable situations.

The forms of the uplands are so much more mature 

than those of the Pliocene valleys that there is good 

reason to assign for their development a correspondingly greater span of time. Furthermore, they are 

clearly correlative with the uplands of the Yosemite 

region indeed, they are traceable across the divide 

and continuous with the uplands of that region. From 

evidence already set forth (see p. 23) it appears that 

the Yosemite uplands, representing the "broad valley 

stage,' 1 are of late Miocene age. Accordingly, the uplands of the San Joaquin Basin are also thought to 

have been produced in a cycle of erosion which began 

some time back in the Miocene and continued until the 

latter part of that epoch.

Finally, the tabular summits of Mount Darwin and 

Mount Wallace are, from the evidence of the great 

height to which these summits rise, much older than 

the Miocene uplands. These small but significant platforms are undoubtedly the remnants of a once extensive erosion surface, and they are clearly referable to 

that most ancient erosion surface recognizable in the 

region, of which traces survive on certain summits in 

the Yosemite region and elsewhere in the Sierra Nevada. This erosion surface is thought to be Eocene

m ae;e.

HANGING VALLEYS

The hanging lateral valleys of the San Joaquin Canyon and its main branches present one of the strikingfeatures of the basin. In the glaciated area, especially 

in Middle Fork Canyon, the question arises as to how 

much of the discordance of the hanging side valleys is 

due to glacial erosion and how much of it is due to 

stream erosion; but in the lower canyon where, below 

the limits of glaciation, the laiidforms are essentially 

all stream-sculptured, obviously glacial erosion may be 

ruled out as a complicating factor. It is here, in the 

40-mile stretch of canyon beginning a few miles below 

the mouth of Chiquito Creek and extending to within a 

few miles of the foot of the range, that the hanging 

valleys are especially well developed and numerous.

The explanation is offered that the lateral valleys 

of the lower San Joaquin Canyon are hanging because 

their streams have been unable to keep pace with the 

accelerated trenching of the San Joaquin River following its rejuvenation by uptiltings of the Sierra Nevada. 

The disadvantage of the side streams may be attributed not only to their smaller volume but also, and 

more particularly, to the fact that their courses 

trending southeastward or northwestward, at right 

angles to the direction of tilting were essentially 

unsteepened, whereas the course of the San Joaquin

River trending southwest ward, parallel to the direction of tilting was appreciably steepened.9

Most of the hanging lateral valleys are in two tiers 

or sets, the one much higher than the other. Valleys 

of the upper set are features of the plateaulike uplands, 

that is they hang with reference to the mature Miocene erosion surface. Valleys of the lower set are 

associated with the flanking benches and shoulders of 

the San Joaquin Canyon, that is, they hang with reference to the Pliocene erosion surface. These two sets 

of hanging valleys are quite distinct; those of each set 

are remarkably accordant in level, but no amount of 

adjusting enables one to bring the two sets into accord.

The hanging valleys, no less than the associated 

erosional surfaces, are clearly indicative of two separate and distinct stages in the erosional history of the 

region. They attest to two rejuvenations of the master 

stream induced by two uptiltings of the Sierra Nevada. 

Valleys of the upper set were left hanging as a result 

of the uplift which initiated the Pliocene or "mountain valley" 1 stage of erosion; those of the lower set, 

as a result of the uplift which initiated the Pleistocene or "canyon" stage of erosion. Valleys of the 

upper set, being developed on massive granitic rock of 

an exceedingly resistant nature, have been preserved 

in spite of their great age. Valleys of the lower set, 

being developed on rock which is less massive and 

therefore less resistant to stream erosion, during the 

Pliocene stage became graded to the new base level of 

the master stream, but in the latest or Pleistocene stage 

have become hanging again through the cutting of the 

canyon. The two sets of hanging valleys are analogous to the two upper tiers of hanging valleys in the 

Yosemite region.

RESTORED MIOCENE AND PLIOCENE PROFILES

The hanging valleys of the San Joaquin Basin provide data from which it is possible to reconstruct the 

longitudinal profiles of the San Joaquin River and its 

two main branches for each of the two stages of erosion 

indicated. Similar stream profiles were reconstructed 

for the Merced River and were useful in analyzing 

the erosional features of the Yosemite region (Matthes, 

1930a, p. 33-45; pi. 27). In the San Joaquin Basin 

the reconstruction of profiles is particularly successful 

because hanging valleys are exceptionally numerous, 

and they occur throughout a longer section and farther

8 Erwin (1934, p. 59) observes, for the Minaret District, that the 

relative cutting power of the streams, as a factor in the production 

of hanging valleys, lias depended upon the volume of the streams, the 

resistiveness of the bedrock, and the relation of the stream courses 

to the tilt of the range. He analyzes the hanging valleys of the 

district with these factors in mind. For most hanging valleys at high 

altitudes, glacial erosion must also be taken into consideration.
42 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

down toward the foothills than in the case of the 

Merced River.

The method used is essentially as follows (Matthes, 

1930a, p. 35-36) : The longitudinal profile of a hanging 

tributary valley may be projected with a fair degree 

of accuracy to the axis of the master valley, thereby 

restoring the destroyed lower part of the profile of the 

hanging valley and determining the approximate point 

at which the tributary stream formerly joined the 

master stream. The method assumes, of course, that 

there was originally no break in the profile of the tributary valley, but this assumption is justified in view 

of the mature form of the hanging valley and the 

smoothly concave character of its profile as far down as 

it is preserved. These two characteristics, which all 

the hanging valleys have in common, show that they 

were developed in a protracted cycle of erosion during 

which side streams evolved courses smoothly graded 

clown to the level of the master stream.

If this method is applied to those hanging valleys 

of the San Joaquin River which careful study indicates will yield reliable data, two series of points are 

obtained, indicative of the former level of the San 

Joaquin River at the end of the "broad valley"1 ' or 

Miocene stage of development and the "mountain valley" or Pliocene stage of development. These two 

series of points may be plotted on the longitudinal 

profile of the present San Joaquin River, and when 

connected they give the restored profiles of the river, 

as shown on pi. 2.

The Miocene and Pliocene profiles cannot be reconstructed empirically from the topographic map alone, 

by one unacquainted with the ground. On the contrary, judgment based on close field observation is 

required, as well as sufficient understanding of topographic methods to enable one to appraise the accuracy 

of features shown on the map. The writer has had 

sufficient experience in the topographic mapping of 

difficult mountain country to realize that much has to 

be sketched in from plane table stations with only 

such control as is afforded by intersecting points. 

Traversing along stream courses is as a rule precluded 

because it is too time consuming, and the topographer, 

if at all experienced in this work, will make the most 

of such views as his planetable stations afford to 

sketch the areas of relatively simple configuration such 

as uplands, especially those that are only sparingly 

timbered. Any data relating to hanging valleys based 

on the topographic map must, therefore, be critically 

evaluated before being used. This is illustrated, in 

following paragraphs, by analysis of some of the 

hanging valleys considered in reconstructing the Miocene profile of the Middle Fork of the San Joaquin 

River.

Granite Creek, the first tributary of the Middle Fork 

above the junction with the South Fork, affords a 

particularly reliable altitude point for the restoration 

of the Miocene profile of the Middle Fork. A careful 

plot of its profile shows that in spite of local modifications due to glacial action, including the development 

of a glacial stairway in its upper course, the general 

curve of the preglacial profile is readily reconstructed. 

Differences in the personal judgment of several individuals attempting to make such a reconstruction probably would not prevent their obtaining closely accordant results. The extension of the curve forward to the 

axis of the main canyon involves but little extrapolation. The total length of the upland course of Granite 

Creek (following the West Fork and Post Creek, which 

is really the main headwater branch) is 12.5 miles; the 

extension of the profile from the edge of the upland 

to the axis of the main canyon measures 1.85 miles.

The hanging valley of Granite Creek has been well 

preserved, despite its great age, because of the great 

resistance the stream has had in trenching the massive 

granite that underlies its lower course. The granite 

that extends from Soldier Meadow down to the edge 

of the upland and over a considerable area to the 

southwest is so sparsely fractured that vegetation still 

is very scant in places. Luxuriant meadows, it is true, 

occur on alluvial ground in the shallow valleys, and 

groves of forest trees stand on the gentle slopes where 

granite sand offers at least a thin soil for their roots, 

but the hills and ridges from which the granite sand 

is being stripped are still largely bare. The massive 

structure of the granite, further, is conspicuous in the 

sides of the canyon of the Middle Fork, where it gives 

rise to smooth, unscalable cliffs.

The East Fork of Granite Creek does not afford 

data that can be used for restoration of the Miocene 

profile of the Middle Fork. As will be clear from the 

map, the East Fork of Granite Creek was originally 

a tributary to the North Fork of the San Joaquin, its 

course being southeastward either through the depression now occupied by the Cora Lakes or, farther south, 

through the deeply incised channel north of Green 

Mountain. Its old valley has been so thoroughly remodeled by recurrent glacial action that very probably 

the stream has followed different channels at different 

times during the Pleistocene. Its present course southward through the notch west of Green Mountain is 

undoubtedly due to a diversion brought about by the 

glacier that filled its old valley. The notch itself was 

in all probability produced by an ice lobe that spilled 

southward over a low divide west of Green Mountain.
GEOMORPHOLOGY 43

The point on the Miocene profile of the Middle Fork 

indicated by Granite Creek has an altitude of 6,600 

feet or more; and a very closely accordant point is 

indicated by the profile of the small unnamed tributary 

of Granite Creek that flows past the north end of 

Squaw Dome.

Although the gently sloping upland back of the 

Junction Bluffs, on the southeast side of the Middle 

Fork, and the similar upland back of Lion Point, on 

the northeast side, are almost certainly good-sized 

remnants of the Miocene surface, they afford no data 

that can legitimately be used in the restoration of the 

Miocene profile of Middle Fork. Only short streamlets traverse these wooded uplands, and as the contouring must necessarily have been sketched by eye from 

planetable stations on distant summits, it can hardly 

be relied upon to give trustworthy results.

The upland course of Crater Creek presumably has 

a fairly reliable profile curve which may be extended 

to the axis of the Middle Fork. The detail with which 

its crooked, wandering course is mapped affords some 

guarantee of accuracy in altitudes. The fact that the 

streamlet reaches the edge of the upland between the 

two Reel Cones, which must have been located by planetable intersections and doubtless have well-determined 

elevations is, further, some guarantee of the accuracy 

of the altitude of the stream to the edge of the plateau. 

Due allowance must be made for glacial erosion at the 

head of the valley, but this cannot have been extensive. As the contour lines on the topographic map 

plainly show, the lower part of the upland course of 

Crater Creek is incised below the original profile of 

the Miocene cycle, and is therefore disregarded.

Fish Valley may be considered, as a final example. 

This valley has been so profoundly altered by glaciation that its earlier profiles cannot be determined with 

confidence. But several of the lower tributaries of 

Fish Creek, notably Silver Creek, the west fork of 

Silver Creek, the unnamed streamlet to the west of 

the west fork, and the streamlet that descends from 

the upland to the north, into the head of Fish Valley, 

furnish mutually accordant points that define probably 

with a fair degree of accuracy a stretch of 3 miles of 

the Miocene profile of Fish Creek. The curve of this 

profile, extended downstreamward, accords well with 

the profile of the Middle Fork of the San Joaquin as 

determined by the two nearest tributaries, Stairway 

Creek below, and Crater Creek above.

The Pliocene profile of the San Joaquin Eiver, as 

is showT n on plate 2, has been reconstructed, from altitude points provided by the lower tier of hanging 

valleys, for a distance of about 60 miles below the 

junction of the Middle and South Forks. This profile

extends, therefore, to within a few miles of the mouth 

of the San Joaquin Canyon. From its lowest point, 

at Fine Gold Creek, upstream to the junction of the 

Middle and South Forks, the profile steepens gradually 

and quite regularly.

The Pliocene profile has been reconstructed for a 

distance of about 12 miles up the Middle Fork to a 

point provided by the hanging valley of Stairway 

Creek. If the profile be extended beyond this point, 

through the glacially remodeled and deepened upper 

valley of the Middle Fork, it reaches to a point about 

3 miles above Agnew Meadows, which is believed to be 

the approximate position of the head of the Pliocene 

valley.

The Pliocene profile has been reconstructed up the 

South Fork for a distance of about 14 miles, from 

points provided by the hanging valleys of Four Forks 

Creek and Rattlesnake Creek. If the profile be extended on up the South Fork, through the glacially 

remodeled and deepened upper valley, it meets the floor 

of Evolution Valley at an accordant level. This valley, which now hangs about 600 feet above the floor of 

the main valley (fig. IT), appears to be the glacially 

modified head of the Pliocene valley (Matthes, 1925, 

P-41).

Similarly, the Miocene profile of the San Joaquin 

River has been reconstructed, from altitude points 

provided by the upper tier of hanging valleys, for a 

distance of about 27 miles below the junction of the 

Middle and South Forks. The lowest point on this 

profile, at Jose Creek, is about 40 miles from the mouth 

of the canyon. Throughout this section, the slope of 

the profile is quite uniform.

Above the junction, the Miocene profiles of both the 

Middle Fork and the South Fork are better documented than the corresponding Pliocene profiles, as 

there are more altitude points, some even within the 

upper valleys.

The Miocene profile has been reconstructed for a 

distance of SO1/^ miles, up the Middle Fork to a point 

provided by the hanging valley of Garnet Lake. 

There is a marked steepening of the gradient as far 

as Crater Creek, but above this point the profile flattens, as far as the uppermost point, at Garnet Lake. 

If the profile is extended a short distance beyond this 

point, it reaches the basin of Thousand Island'Lake 

at an accordant level. This basin, which lies about 

1,650 feet higher than Agnew Meadows, is apparently 

the glacially modified head of the Miocene valley.

The Miocene profile has been reconstructed 34 miles 

up the South Fork to a point provided by the hanging 

valley in which Heart Lake is situated. Throughout
44 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

this distance, the profile steepens progressively. If 

the profile is extended on up through Evolution Valley, with a gradient that continues to steepen, it joins 

the floor of Evolution Basin at an accordant level. 

This basin, which hangs more than a thousand feet 

above the head of Evolution Valley, appears to be the 

glacially modified head of the Miocene valley (Matthes, 

1925, p." 41).

It is to be noted that if the reconstructed Middle 

Fork and South Fork profiles of either the Miocene 

or the Pliocene set are compared for the sections above 

the junction wherein both sets are ^represented, those 

of the Middle Fork are steeper than those of the South 

Fork. In these sections, the two branches of the San 

Joaquin River are oriented at right angles to each 

other, the Middle Fork flowing southwestward, directly 

down the west slope of the range, and the South Fork 

flowing northwestward, along the slope and parallel 

to the crest of the range. As a result of this difference in orientation, the ancient profiles of the Middle 

Fork have been steepened by the uptiltings of the 

Sierra Nevada, whereas the corresponding profiles of 

the South Fork have remained unsteepened or have 

been steepened to a negligible amount. The decrease 

in slope of the Miocene profile of the Middle Fork, 

between Crater Creek and Deadman's Pass, probably 

reflects the change in trend of the river, which in this 

section has a southerly course; and the further flattening of this profile above Deadman's Pass probably 

reflects the southeastward course of the river in this 

section.

These relationships in the San Joaquin Basin are 

consistent with those which have been found farther 

north in the Sierra Nevada, where the reconstructed 

Tertiary profiles of other rivers similarly show steepening in those sections of their courses that trend 

parallel to the direction of tilting, and lack of steepening in those sections where their courses are at 

right angles to that direction (Lindgreii, 1911, p. 

46-48; Matthes, 1930a, p. 43-44).

SIGNIFICANCE OF PATTERN OF RIDGES AND VALLEYS

The hills, mountain groups, and long mountain 

ranges standing above remnants of the Miocene erosion 

surface are monadnocks and, in all probability, are 

features inherited from the system of northwestward 

trending ridges that occupied the place of the present 

Sierra Nevada in Late Jurassic and Cretaceous time. 

The folded sedimentary and volcanic beds have been 

largely worn away from most of these ranges, as at 

Kaiser Ridge, and only the cores of granitic rock 

remain; but in a few instances, notably the Ritter

Range and the LeConte Divide, the metamorphic beds 

still remain in large volume.

Recognition of the mountain crests as features inherited from the older mountain systems carries with 

it, by implication, the recognition of the northwestward-trending valley troughs between them as similarly inherited features. It would appear, therefore, 

that the South Fork of the San Joaquin River follows 

a valley that dates far back into Cretaceous time, and 

that the same is true of the other northwestwardtrending valleys, such as those of Chiquito Creek, 

Granite Creek, the North Fork, and the upper course 

of the Middle Fork.

In the case of the South Fork, the head-ward part 

of the river still flows over the metamorphic rocks, to 

whose structure it long ago became adjusted and in 

which Goddard Canyon has been excavated. Throughout the rest of its course, however, the South Fork 

flows over granite. The South Fork in this section, 

and also the other longitudinal streams in the basin 

which similarly are now cutting in granite, are believed to have acquired their northwesterly or southeasterly courses largely by superposition from the 

metamorphic rocks. Their trends over the areas of granitic rock still reflect the pattern of the ancient drainage which had become extensively adjusted to the 

structure of the Appalachian-type mountains (Matthes, 

1930a, p. 2).

The canyons of the North Fork and the upper part 

of the Middle Fork also are cut in metamorphic rocks, 

and their courses conform in large part to the structures of these rocks (Erwin, 1934, p. 55). The southeasterly trend of the canyon of the Middle Fork, from 

the vicinity of Agnew Pass to a point about a mile 

below Agnew Meadows, accords with the strike of the 

upturned beds and the parallel system of strike faults. 

The course of the river coincides approximately with 

the trace of one of these faults for a distance of several miles. Several small tributary streams on the 

east side of the canyon likewise follow the strike 

throughout the major part of their courses. The canyon of the North Fork, taken as a whole, has a more 

southerly trend than the strike of the beds, but when 

examined in detail its course is found to consist of four 

long southeastward-trending segments that have southwesterly trends, across the strike. Most of the tributary streams 011 the west side of the North Fork flow 

southea st ward.

Similar structural control is evident in the Ritter 

Range, whose major laiiclforms, and also certain of 

its minor ones, trend parallel to the strike of the metamorphic rocks (Erwin, 1934, p. 9). The great height 

of the range doubtless is due to the superior resistance
GEOMORPHOLOGY 45

to erosion of the rocks which make up its bulk. The 

LeConte Divide probably illustrates the same relationships. 10

Over wide areas, however, correspondence of this 

kind between landforms and the constituent rocks, or 

their structures, is not evident. Presumably in these 

places the lithologic dissimilarities either were not 

such as to cause noteworthy topographic contrasts, due 

to differential weathering and erosion, or else the contrasts were obliterated during the long Tertiary cycles 

of erosion. Thus in the northern part of the basin, 

none of the projecting tongues of metamorphic rock, 

whether in the western, southern, or southeastern margins of the metamorphic area, finds expression in the 

primary or even in the secondary features of the topography. One cannot infer the windings of the contactbetween metamorphic and granitic rocks from the positions and forms of ridges or valleys. The latter features appear to have been carved indifferently across 

both kinds of rock, and the trace of the contact wanders among and over them without attendant changes 

in style or topography, except perhaps in the minutely 

sculptured details.

In connection with the course of the San Joaquin 

River, the broad sag in the crest of the range at Mammoth Mountain appears to be of critical significance. 

Mayo (1941, p. 1068, 1081, pi. 3) points out that this 

sag lies at the southwestern corner of the ''Mammoth 

reentrant" in the eastern front of the Sierra Nevada. 

The reentrant coincides with a complex of intersecting 

faults. The latter probably played an important part 

in determining not only the reentrant but also the

10 The investigations of Erwiii (1934) and Mayo (1937, 1941) made 

subsequent to this reconnaissance, indicate that joint patterns also 

have been highly influential in determining drainage and topographic 

patterns in the central and southern parts of the Sierra Nevada. Mayo 

(1941, p. 1053) has found that the steep, primary joints are features 

inherited from the oldest structural patterns of the range.

By mapping the joints that dip more than 60°, Mayo (1941, p. 1050- 

1053, pi. 2) has shown that throughout a considerable part of the 

Sierra Nevada, including a portion of the San Joaquin Basin, there are 

four principal joint sets. These trend, respectively, west-northwest, 

northwest, north-south, and northeast.

The northwest joints are especially well developed and important 

as a topographic influence. For example, according to Mayo (1941, 

p. 1052) "in the Mt. Goddard quadrangle, many canyons, such as 

First and Second Recesses, and Goddard Canyon, trend northwestward 

. . . Throughout the area the sculpturing of many a bold peak and 

sharp ridge has been partly controlled by the orientations and spacings 

of northwest joints."

Adjustment to north-south joints may explain the course of the 

Middle Fork in the section south of Pumice Flat (Mayo, 1937, p. 181).

In the metamorphic rocks of the Ritter Range, Erwin (1934, p. 56) 

noted that the northeast set of joints is best developed, and it is 

reflected in topographic features of the sharp and rugged Minarets.

Mayo (1941, p. 1052) states that the northeast joints "are followed 

by many of the master streams that drain the western slope of the 

Sierra Nevada and by most of the canyons that furrow its eastern 

scarp. Along the crest of the range . . . swarms of northeast joints 

are responsible for jagged irregularities in the skyline of the northwesttrending ridges."

development of the sag and the localization of the 

intrusive rocks in it. This sag is thought to be the 

mouth of a Tertiary valley which extends far to the 

eastward and w^hose stream joined the Middle Fork 

when the waters from the country to the east still 

drained westward across the Sierra region. The 

Middle Fork flowed in a relatively shallow valley 

slightly below the level of the sag and below the 

shoulders that now flank the canyon. It seems probable, in view of the depth and breadth of the sag, that 

the valley indicated by it was then occupied by a 

large river the San Joaquin and that that part of 

the present South Fork, which pursues a general 

southeasterly course from Thousand Island Lake to 

the Devils Postpile, was merely a tributary of the 

master stream. The San Joaquin River, therefore, 

appears to be a ''beheaded' 1 stream, its original upper 

course having been cut off as a result of the faulting 

which produced the Sierra escarpment. Several other 

Sierra streams besides the San Joaquin, that now begin 

in gaps in the crest of the range, doubtless were similarly decapitated.11

RELATION OF MAIN DRAINAGE DIVIDE TO ESCARPMENT ON 

EAST SIDE OF RANGE

At the head of the San Joaquin Basin the main 

drainage divide, or crestline, does not coincide with 

the top of the great east escarpment of the Sierra 

Nevada except at two very short stretches. Throughout the rest of its 70-mile course, the main drainage 

divide bears no constant relation to the escarpment, 

but is separated from it, in places by intervals of many 

miles, and is a wholly independent feature in regard 

to altitude and trend.

It is evident that the main drainage divide is an 

erosional feature, and is of much greater antiquity than

11 The interpretation of the San Joaquin River set forth above is the 

one which Matthes published (1930b). In unpublished and) undated 

notes he has also given the following interpretation, which assumes 

that the San Joaquin River has had much the same history as that of 

the Merced River (Matthes. 1930a, p. 30-H1). According to this interpretation, the San Joaquin River established its course conformably to 

the southwestern slant of the region, presumably early in the Tertiary 

period, when the first upwarpings or tiltings occurred that determined 

the southwestward direction of nearly all the master streams of the 

Sierra Nevada. As it grew headward it did so at the expense of the 

streams of the older drainage system, which were successively captured. 

The dividing ridges probably did not stand in the way of this capturing 

as much as might be supposed, for they were discontinuous, with 

many saps. Among the captures made by the San Joaquin were those 

of the South Fork and the upper part of the Middle Fork. The sag 

in the crest of the range may simply mark a low divide; it may 

indicate an ancient valley through which the upper course of Middle 

Fork flowed northeastward, before it was captured ; or it may record 

the valley of a former tributary to the Middle Fork.

Recent stream capture, of the type postulated by this interpretation, 

is illustrated on a small scale by Stevenson Creek. The former head 

of this creek flowed northwestward into the Shaver Lake Basin, but it 

was captured by the small stream of Blue Canyon, which flows southsoutheast, into the Kings River.
46 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

the escarpment: an ancient divide which parted northeastward-flowing waters from southwestward-flowing 

waters long before tectonic movements gave rise to 

the escarpment. The forms and gradients of the upland valleys to the northeast of the divide are closely 

similar to the corresponding features of the upland 

valleys on the southwest side, showing that prior to 

the formation of the escarpment, the Sierra region 

fell off rather symmetrically in both directions. Ancient erosional features like those referred to above, 

of Miocene and Pliocene age, are found only at high 

levels of the eastern slope.

The east escarpment is probably largely of early 

Pleistocene origin, and is a feature produced as a 

result of the clownfaulting of the Owens Valley graben. 

There is reason to believe that it did not assume its 

imposing height until after the Sierra Nevada had 

undergone its first period of glaciation. For, whereas 

the moraines of the Sherwin, Tahoe, and Tioga stages 

of Blackwelder (1931) lie at the mouths of the deep 

canyons that gash the east mountain front, certain 

moraines of Blackwelder's earliest, the McGee stage, 

are situated on a high shoulder overlooking the escarpment, where they could have been deposited only before 

the canyons w^ere cut to their present depth. (Matthes, 

1933a, p. 35-39; 1950b, p. 42-50.)

GLACIATION

During the Pleistocene epoch, the higher parts of 

the San Joaquin Basin, like those of the other basins 

on the west slope of the Sierra Nevada, were mantled 

repeatedly with glaciers.12 Practically all of the glacial sculpturing that gives the High Sierra its distinctive scenic aspect, has been superimposed on a 

landscape inherited from Miocene and Pliocene times 

(Matthes, 1933a, p. 37). While the San Joaquin Eiver 

was cutting its sharply V-shaped gorge in the lower 

slope of the Sierra, the untrenchecl Pliocene valleys 

of the upper slope were being vigorously glaciated and 

transformed into broadly U -shaped troughs. The little 

side valleys on the Miocene uplands, which already 

were hanging above the Pliocene main valleys, were 

occupied by tributary glaciers and as the side valleys 

underwent less excavation than the main valleys, the

12 Distribution of the Pleistocene glaciers for the entire Sierra Nevada 

is shown on the Glacial Map of North America (scale 1:4,555,000), 

published by the Geological Society of America, New York, 1945. This 

map distinguishes between the Wisconsin and the pre-Wisconsin 

(undifferentiated) glaciations.

Distribution of the late Pleistocene (Wisconsin) glaciers for the 

entire Sierra Nevada is shown on an inset map printed on Sheet No. V 

of the Geologic Map of California (scale 1:500,000), published by the 

Division of Mines, California Department of Natural Resources, San 

Francisco, 1938. The north half of this glacial map is by Eliot 

Blackwelder (1932.), the south half by F. E. Matthes (1987).

discordance between the two was generally increased. 

The heads of the little Miocene valleys carved in the 

flanks of the High Sierra crests were resculptured into 

amphitheaterlike cirques. The latter were cut deeply 

into the tabular remnants of the Eocene surface that 

persisted on the higher peaks, but on Mount Darwin 

and Mount Wallace, the remnants were not wholly 

consumed. These summits escaped glaciation and 

were subject only to iiivation.

In the San Joaquin Basin the same method was 

employed for tracing and mapping the courses of the 

ancient glaciers and for determining the farthest limits 

which they had reached that had proved effective, previously, in the Merced and Tuolumne basins. That 

method relies on the testimony of glacial deposits 

rather than on that of sculptured features, and consists primarily of a systematic survey of the moraines 

which were built by the individual glaciers.

In open country, such a survey can be executed readily with sufficient accuracy for a reconnaissance map 

on the scale of 1:125,000 by locating the moraines 

by eye with respect to identifiable landmarks; but in 

the forested tracts, the more important moraines must 

be actually followed out and, in some places, even 

located by traverse a laborious and time-consuming 

process. Fortunately, the forested areas in the San 

Joaquin Basin, though of considerable extent, are so 

amply diversified by topographic drainage features, 

as well as by occasional meadows, that no traversing 

was needed, and a large share of the work could be 

done by following the moraines, or the swales between 

moraines, on horseback. In the rougher areas, of 

course, the mapping had to be done on foot.

In spite of the rapidity with which the survey was 

carried out in a rugged mountain region largely devoid 

of roads, and only scantily traversed by trails, the 

resulting map (pi. 1) is probably of more than reconnaissance accuracy, for it shows not merely the areas 

that were formerly ice covered but also, by rows of 

dots, the crestlines of the individual moraines of the 

later glaciation. These crestlines, it is evident, tell 

the story of the glacial invasions, and the minor fluctuations of the glaciers, more precisely and more 

graphically than can mere words.

In the central part of the basin, which contains the 

outer fringes of the glaciated territory, special pains 

were taken in the mapping of the glacial deposits, as 

a definite knowledge of the extreme limits of glaciation is of paramount importance in the correct analysis 

of the landscape. It was necessary to do this work 

with more care as the outermost glacial deposits in 

most places are older than the Wisconsin and generally 

consist of small, obscure patches no longer identifiable
GLACIATION 47

by their topographic forms. It is due largely to that 

circumstance that the true extent of the former glacial 

mantle of the Sierra Nevada long remained in doubt 

and a subject of misconceptions.

Reliance was not placed on topographic forms as 

possible indicators of changes wrought by glacial erosion because, as had been learned in the Yosemite 

region and in the Tuolumne Basin (Matthes, 1930a, 

p. 89-91), the extraordinarily varied joint systems in 

the granitic rocks of the Sierra Nevada in large measure controlled the eroding action of the ice. The 

joints more than any other factor determined whether 

a V-shaped river canyon would or would not be transformed into a typical U-shaped trough. Where the 

granite is thoroughly divided by joints (figs. '28, W29), 

glacial plucking, or quarrying, was particularly effective and typical glacial forms were actually produced; 

but where the joint features are spaced far apart, or 

are wholly absent over distances of hundreds and even 

thousands of feet, glacial action was reduced largely 

to abrasion, and only minor changes were effected in 

the valley form. Even the Tuolumne Glacier, which 

attained a length of 60 miles and a depth of 4,000 feet, 

failed to give its canyon a typical U-shaped form 

throughout, because the walls, for mile after mile, are 

composed of prevailingly massive granite.

It was discovered also, in the Yosemite region, that 

hanging valleys, on the western slope of the Sierra 

Nevada, are not necessarily indicative of profound 

glacial erosion, many of them having gained their 

hanging aspect long before the glaciers appeared upon 

the scene, simply as a result of rejuvenation of the 

master stream induced by the tilting of the Sierra 

block. Many hanging side valleys occur in the lower, 

unglaciated courses of the main canyons as well as 

in the intensely glaciated upper courses.

FIGURE 28. Hackly surface produced by glacial plucking of jointed 

bedrock. On crest of ridge west of Evolution Basin, looking eastward. Mount Huxley in distance. Photograph by G. K. Gilbert.

FIGURE 29. Valley floor modified by glacial plucking in jointed bedrock. Ice movement from left to right. Upper Evolution Valley. 

Photograph by G. K. Gilbert.

Ill the San Joaquin Basin, therefore, it likewise 

was deemed best to regard the varying forms of the 

canyons and, indeed, of all the features of the glaciated 

landscape, as things to be explained rather than as 

features diagnostic of past events.

In the moraiiial deposits of the San Joaquin Basin, 

as in the Yosemite region, abundant and unmistakable 

evidence was found of two distinct stages of glaciatioii 

separated by a lengthy time interval: also meager 

indications of a third, very early stage (Matthes, 1929). 

Many examinations of the morainal deposits of the 

two easily recognizable glacial stages in this basin 

confirm the interpretations of the moraine systems of 

the Yosemite and Tuolumne regions and help establish the succession of events making up the glacial 

history of the west slope of the Sierra.

It should be added that in later years much corroborative evidence has been found in the Kings River, 

Kaweah, and Kern Basins. Throughout the southcentral Sierra Nevada, therefore, the morainic systems 

of the great trunk glaciers and their numerous branches 

spell out the same story of three distinct stages of 

extensive and long-continued glaciatioii during the 

Pleistocene epoch.
48 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

DIFFERENTIATION OF MORAINES AND CORRELATION OF GLACIAL STAGES

For discriminating between moraines belonging to 

the different stages of glaciation it was found best, in 

the San Joaquin Basin, to apply the criteria which the 

writer had developed in the course of his detailed 

studies of the Yosemite region, because the general 

nature of the country in the two areas, the character 

of their rocks, the climatic conditions, the vegetal 

cover, and the soils are closely similar.

On the glacial map (pi. 1) distinction is made only 

between the Wisconsin and pre-Wisconsin stages. Although at some localities (see pages 56, 57-58) the 

field data appear to warrant subdivision of the Wisconsin moraines into those of early Wisconsin time 

and those of late Wisconsin time, corresponding to the 

Tahoe and Tioga stages of Blackwelcler (1932), such 

division could not, in the time available for the reconnaissance surveys, be carried consistently over the 

entire area. In many places the moraines of early 

and late Wisconsin time are so closely alike that their 

separate mapping would have required detailed and 

prolonged study. All the moraines of the Wisconsin 

stage are therefore shown on the map provisionally 

as a single unit. The data, nevertheless, are sufficiently detailed to permit individual moraine crests to 

be indicated by rows of clots.13

The moraines of the Wisconsin stage as a rule are 

well preserved, sharp-crested, and studded with freshlooking unweathered boulders. A few weathered and 

even thoroughly decomposed boulders occur, but it is 

evident from their sparse occurrence in deposits composed almost wholly of fresh, un weathered rocks that 

ring under the hammer, that the weathered boulders 

represent an admixture of material that already was

13 Detailed study of the glacial record along the South Fork of the 

San Joaquin River and its tributary, Mono Creek, has recently been 

made by Birman (1954). In this region, Birman reports the occurrence of seven moraine sets, which he has divided into three groups. 

"Group I, the oldest, contains highly weathered erratics and till. 

Original morphology has been largely destroyed. Group II contains 

three sets of well-formed moraines, each with distinctive weathering 

characteristics. End moraines are virtually absent in the earliest set, 

scarce in the intermediate set, and present at about 7,000-feet elevation 

in the latest set. Group III contains three moraine sets mostly 

above 8,500 feet. Distinct reversal of weathering ratio in the oldest 

set suggests minor short-lived glaciation long after withdrawal of 

Group II ice. The youngest set includes bare, unstable rock glaciers 

and moraines at cirque headwalls. The intermediate moraines occur 

as much as a mile from cirque headwalls. Abundant lichens and 

tree-ring counts indicate a minimum age of 250 years.

"Work in upper Rock Creek and visits to other Eastern Slope 

canyons tentatively suggest that: (1) Group I deposits are largely 

Sherwin in age; (2) in Group II, the earliest and latest sets closely 

resemble respectively Tahoe and Tioga moraines ; (3) the intermediate 

set of Group II occurs in Eastern Slope canyons as moraines apparently 

distinguishable both from Tioga and from Tahoe deposits ; (4) Group 

III moraine sets record minor advances, probably since Climatic 

Optimum."

considerably weathered when the glacier picked it up, 

perhaps from moraines of earlier glacial stages. It 

is significant, moreover, that in these younger moraines 

not only the boulders of siliceous granite but even 

those of much weaker cliorite and gabbro are essentially 

uiiweathered and unstained.

The pre-Wisconsin moraines in the San Joaquin 

Basin are in all respects closely similar to those in 

the Yosemite region, and are therefore referred to the 

El Portal stage. Compared to the moraines of the 

later stage, they are poorly preserved, and generally 

are cloaked with granite sand derived from their own 

disintegrating boulders. In places, the boulclery character of the ancient moraines is shown mainly in 

exposures made by uprooted trees. The boulders in 

the interior of the moraines are, as a rule, encased in 

ferruginous rinds; many are entirely decomposed, so 

that they may be cut with a shovel. Although originally of much greater bulk than the moraines of the 

Wisconsin stage, the older moraines have long since 

lost their crests, and their form has become subdued 

and flattened. Over considerable distances they have 

not only lost their riclgelike aspect but have become 

inconspicuous in the landscape. The accumulation of 

sand on the upslope sides of morainal ridges in some 

places has largely concealed them.

Terminal moraines of the El Portal stage appear to 

be generally absent in the main canyons on the west 

slope of the Sierra Nevada. At least, methodical 

search has failed to reveal any remnants of such 

moraines in the principal canyons of the Stanislaus, 

Tuolumne, Merced, San Joaquin, Kings, Kaweah, and

FIGURE 30. Details of ice-scoured rock floor of Evolution Basin, near 

Sapphire Lake. In lower right-hand corner are two crescentric 

gouges. In left center are curved tension cracks in parallel overlapping series. The ice came from the left.
GLACIATION 49

FIGURE 31. rrescentric gouge* Bear base of Mount Huxley. The rock 

face is inclined toward the foreground at 45°. The ice motion 

was from risen t to left. A pocket knife inserted in one of the 

central goujres of the lower tier gives the scale. Photograph by 

G. K. Gilbert.

Kern basins. Their total absence can hardly be explained as the result of post-El Portal stream erosion 

and collateral slope-wash, slumping, and other degrading processes; for in some of the canyons, notably in 

the San Joaquin Canyon, the local conditions are distinctly favorable for the preservation of at least the 

wings of terminal moraines and recessional moraines, 

but no vestiges of such remain. It seems probable, 

therefore, that the glaciers of the El Portal stage did 

not maintain their maximum extension long enough 

to build bulky terminal moraines.

The El Portal stage is believed to correspond to 

Black welder's Sherwin stage at the east base of the 

range (Blackwelder, 1932), and is thought to be not 

younger than the Illinoian stage of the continental 

glaciation (Matthes, 1933b, p. 72, 76: 1935). In the 

San Joaquin Basin as in the Yosemite region, however, these older moraines differ considerably among 

themselves in degree of preservation and in the decomposition of their granitic boulders, and it therefore 

seems entirely possible that they include remnants 

of two or more as yet unseparated stages that differ 

considerably in age, including perhaps both the Kansaii 

and the Illinoian (Matthes, 1933a, p. 33). Only intensive studies in selected areas are likely to settle that 

question. The correlation of the older glacial deposits 

of the Sierra Nevada must necessarily remain tentative until the glacial field of the Pacific ranges has 

been more closely connected with the glacial fields of 

the Rocky Mountains and the Great Plains.

No morainal deposits belonging to the Glacier Point 

stage, the earliest stage of glaciation that was recognized in the Yosemite region, are shown on the map; 

but it is not to be inferred from this that no deposits 

whatever of that early glaciation remain preserved in 

the San Joaquin Basin. A few small, isolated patches 

of an ancient moraine were discovered in the central 

portion of the basin, on a mountain summit at a high 

level above the surrounding canyons, and these may 

well be representative of the Glacier Point stage, in 

view of their elevated positions.14 The deposits of 

the Glacier Point stage thus far discovered, notably 

those in the type locality in the Yosemite region, on 

the divide to the east of Mount Starr King (Matthes, 

1930a, p. 73-74), are situated at a great height above 

the neighboring canyons, which would seem to imply 

either that the Sierra Neavda at one time was fairly 

overwhelmed with ice, or that a great de.il of canyon 

cutting has taken place since these ancient moraines 

were laid down. As the latter hypothesis seems the 

more probable of the two and finds support in a variety 

of circumstantial evidence, there is good reason for 

assigning the Glacier Point stage, together with Blackwelder's McGee stage, to the early Pleistocene presumably corresponding to the Nebraskan stage 

(Matthes, 1933a, p. 33). In the San Joaquin Basin, 

meanwhile, until more conclusive proof is forthcoming 

that the isolated patches of morainal material mentioned are of decidedly greater antiquity than the 

deposits of El Portal age, it seems best not to differentiate them from the latter on the map.

GLACIERS OF THE PRE-WISCONSIN STAGES

The San Joaquiii glacier system of the pre-Wisconsin stages was by far the largest system of confluent 

glaciers in the Sierra Nevada, measuring more than 

50 miles in length along the crest of the range and 

30 to 35 miles wide. Of the 1,760 square miles comprised in the San Joaquiii Basin, almost 1,100 square 

miles were covered by glaciers. This ice mass, together with the ice masses in the basins of Dinkey 

Creek and the North Fork of the Kings River, formed 

a mer cle glace 1,500 square miles in extent. Yet it 

was not an icecap, strictly speaking, for its surface 

was broadly concave rather than dome shaped. It 

consisted of a large number of confluent glaciers that 

had descended from the surrounding peaks and crests, 

filled the canyons, and overflowed onto the intermediate uplands (Matthes, 1947, p. 208; l950b, p. 62).

The San Joaquiii glacier system was essentially bilobate, in that it comprised two great primary branches

14 No references to the exact location of these deposits, or descriptions 

of them, were found in any of Matthes' field or office notes, and the 

only information available is that given above, which is taken from a 

brief published paper (Matthes, 1935).
GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN. CALIFORNIA

that descended Middle Fork and South Fork canyons. 

The branches united below the junction of the two 

forks, to form a very broad trunk glacier that overflowed the main San Joaquin Canyon and spread 

widely over the central part of the basin, northeast of 

Chiquito arid Kaiser Ridges. The glacier ended in a 

rather blunt tongue, only a few miles long, which lay 

in that part of the main canyon which separates Chiquito and Kaiser Ridges. The length of the San 

Joaquin glacier system, measured from Muir Pass at 

the head of the South Fork branch to the terminus of 

the trunk glacier, 1^4 miles below the mouth of Rock 

Creek, was nearly 60 miles. The length measured 

along the Middle Fork branch was almost 45 miles. 

The shortness of the trunk glacier, which descended to 

a point about 14 miles below the junction of the 

Middle and South Forks, is explained by the fact that 

the ice which spread over the vast expanse of rolling 

uplands bordering the canyon was dissipated by ablation much more rapidly than it would have been if it 

had been concentrated in a deep cliff-shaded trench.

Ice was contributed not only from areas along the 

crest of the range but also from all sides of the various 

ridges on the west slope, except in the case of Chiquito 

Ridge, which, because of its low altitude (maximum 

8,358 feet), developed glaciers only on its north side. 

The glaciers of the south side of Kaiser Ridge were 

tributary not to the main San Joaquin glacier system 

but to a separate and much smaller system in the 

basin of Big Creek.

MIDDLE FOBK GLACIER

Middle Fork glacier, in conforming to the course of 

the canyon which it occupied, flowed successively 

northeast, southeast, south, and finally southwest, to 

its junction with the South Fork glacier. Its length, 

from its source on Mount Davis to its junction with 

the South Fork glacier, \ mile southwest of Balloon 

Dome, which was overridden by the ice, \vas 31 miles.

In its upper course, the sources of this glacier lay 

at altitudes of 10,000 to over 13,000 feet 011 the northeast slope of the Ritter Range, mainly in the basins of 

Thousand Island Lake, Garnet Lake, Shadow Creek, 

Minaret Creek, and King Creek. As these sources 

were situated to the west of the main trunk, the upper 

part of Middle Fork glacier wT as highly asymmetrical.

Farther downstream, Middle Fork glacier was augmented by large tributary glaciers, notably those in 

the valleys of Fish Creek, North Fork, and Granite 

Creek. These glaciers filled their valleys and, overflowing the intervening divides, became confluent in 

most places.

Fish Creek glacier, which was IT1/^ miles long, measured from Red and White Mountain to its junction 

with the Middle Fork glacier, originated, for the most 

part, in cirques at altitudes of 10,000 to 12,000 feet on 

the main crest of the Sierra and on the north side of 

the Silver Divide. North Fork glacier, which was 

lQi/2 miles long, measured from Rodgers Peak to its 

junction with the Middle Fork glacier, was fed principally from areas on the southwest and south sides of 

the Ritter Range, and from basins at altitudes of 

10,000 to 12,000 feet on the southeast side of the nameless crest trending southwest from Mount Lyell. Granite Creek glacier, which was 14 miles long, measured 

along its west branch, had its main sources at altitudes 

of 9,500 to 11,000 feet 011 the crests which bear Black, 

Sing, Gale, and Triple Divide Peaks.

South Fork glacier, measured from the head of 

Evolution Creek at Muir Pass to its junction with 

Middle Fork glacier 1 mile southwest of Balloon 

Dome, was 46 miles long. Throughout most of its 

course it flowed northwestward, its consistent trend 

being in marked contrast to the course of the Middle 

Fork glacier. South Fork glacier received much of 

its ice from cirques on adjacent mountains and from 

its many tributary glaciers, most of which joined it 

from the east and northeast. The most important 

tributaries were Godclard Canyon glacier, Piute Creek 

glacier, Bear Creek glacier, and Mono Creek glacier.

The upper part of the South Fork glacier, which 

occupied Evolution Valley and Evolution Basin and 

therefore may be called the Evolution glacier, was 

\ 1 miles long, measured from Muir Pass to its junction 

with Goddarcl Canyon glacier. It was fed from 

cirques at altitudes of \ 1.500 to over 13,500 feet, located 

at its head along the main crest of the range, and 

from others on the high confining ridges, such as 

Glacier Divide and the nameless ridge which bears 

Mount McGee.

Goddarcl Canyon glacier was 8y2 miles long, measured from the divide south of Martha Lake to its 

junction with the Evolution glacier. Its sources lay 

in cirques at altitudes of 11,50U to 12,500 feet on the 

bordering ridges, especially on the LeConte Divide; 

but much ice was also contributed from the cirques at 

its head whose walls rose to the lofty summits of 

Mount Goddarcl and Mount Reinsteiii.

Piute Creek glacier, a branching ice body 11 miles 

long measured to its head on Mount Emerson, wT as fed 

mainly from several enormous compound cirques that 

ranged along the crest of the range at altitudes of 

11,000 to over 13,000 feet, the largest of these. Plum-
51

phrey's Basin, being more than 3 miles across. However, throughout the course of this glacier the lateral 

cirques along both sides contributed notably to its volume for example those at 11,500 to 13,000 feet on the 

north slopes of Glacier Divide.

Bear Creek glacier and Mono Creek glacier were 

tributaries of even greater length and complexity. 

Bear Creek glacier was 15 miles long, measured up 

Hilgarcl Branch, and headed at altitudes of 10,000 to 

over 13,500 feet mainly in cirques on the south side of 

Mono Divide, and 011 the northwest side of a long 

curving nameless crest which bears Mount Senger and 

Mount Hooper. Mono Creek glacier was 20 miles 

long, measured to Mount Mills, and accordingly was 

the longest tributary of the South Fork glacier, and 

longer than any tributary of the Middle Fork glacier. 

Its most important sources lay on the main crest of 

the range, between Mount Abbott and Red and White 

Mountain, at altitudes of 10,000 to over 13,500 feet; 

others were located to the north on the Silver Divide, 

and to the south on the Mono Divide.

CENTRAL ICEFIELD

The union of the Middle Fork and South Fork 

glaciers produced an enormous volume of ice which 

overflowed the canyons and spread broadly across the 

plateaulike uplands, forming a practically continuous 

icefield.

At the northwest this icefield was augmented by 

several confluent glaciers which descended the valleys 

of Jackass Creek, Chiquito Creek, and other smaller 

southeastward flowing streams. The sources of these 

glaciers lay at altitudes of K,000 to 10,000 feet on the 

northeast slope of Chiquito Ridge and on the southeast slope of the crest just north of Beasore and Mugler 

Meadows. The Chiquito Creek glacier, the largest of 

the group, was about 16 miles long, measured from 

Redtop Mountain to the San Joaquin Canyon at San 

Joaquin Bridge.

West of the junction of the Middle and South Fork 

glaciers, the ice was sufficiently deep to overtop the 

knobs and hills which rise 200 to over 800 feet above 

the uplands Jackass Butte, Jackass Rock, Squaw 

Dome, Cattle Mountain, and others as shown by the 

scattering of erratics all the way to the summits of 

these eminences.

On the rolling country south of Jackass Meadows, 

erratics are in evidence almost everywhere, but there 

are no heavy concentrations of drift. Between the 

Placer Ranger Station and the San Joaquin Bridge, 

the gentle, smoothly rounded slopes of the lower 

Chiquito Creek basin are not visibly affected by the 

presence or absence of the drift (figs. 34, 35). Most

FIGCKE 32. Perched erratic boulder of the earlier ice invasion on 

sloping platform south of Junction Bluffs along the Middle Fork of 

the San Joaquin River, opposite the mouth of Stairway Creek. The 

pedestal is nearly 12 feet high.

of the interfluves are deeply cloaked with loose sand 

derived from disintegrating rock much of it, apparently from boulders in the older drift. Only here 

and there are patches of the drift exposed. Most of 

it consists of rounded, evidently water-worn pebbles 

and small cobbles, which are mixed with more irregularly shaped and typically glacial cobbles and boulders. 

Quartzite, schist, dark-colored porphyry, and lava are 

common, and in places are more abundant than granitic 

rocks.

Northeast of Mugler Meadow, where a wagon road 

crosses Chiquito Creek, glacially striated cobbles are 

present in profusion. There is, northeast of the crossing, what appears to be a terracelike deposit of gravel 

and boulders. In this area the schists are particularly well striated, but the granite cobbles are either 

unstriated or so slightly striated as not to serve as 

diagonistic glacial material. Quartzite and schist are 

plentiful, and are probably derived from the south 

slope of Black Peak, but no trace was found of lava 

such as occurs in the Jackass country, a few miles to 

the east. This drift may be younger than that of the 

earlier glaciation in the Jackass region perhaps in-
52 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

FIGURE 33. Remarkable imitation of a perched erratic boulder of 

granite, produced wholly by weathering in place. Most of the 

weathering has taken place since the passage over this spot of the 

earlier ice. Upper valley of Chiquito Creek, on west side of trail to 

Chiquito Pass.

termediate in age between that drift and the Wisconsin drift to the north. In any event it is not Wisconsin, since in most places it underlies smooth slopes 

covered with granite sand.

Important contributions to the central icefield were 

also made by glaciers that originated at altitudes of 

9,UUU to 10,500 feet on the north slope of Kaiser Ridge, 

and that filled the valleys of Kaiser ("reek and neighboring streams on the upland. Older drift forms a 

more or less continuous veneer covering the slopes on 

both sides of Kaiser Creek, and it is present in large 

quantities in the neighborhood of Kaiser Creek Diggings, where it forms terraces or terracelike benches 

with very steep slopes facing the creek bed. Farther 

north, in the vicinity of Cow Meadow, the scattered 

erratics which are evidence of the earlier ice, are very 

sparse. Mount Tom was a nuiiatak, its summit rising 

1,000 feet above the level of the surrounding ice.

LOWER SAN JOAQUIN GLACIER

Although the central icefield was restrained on the 

southwest arid south by Chiquito Ridge and Kaiser 

Ridge, nevertheless it was not wholly confined by these 

barriers, but discharged southward through the gap 

between the two ridges, by way of the lower San 

Joaquiii Canyon. The extent of this lobe must be inferred from remnants of its lateral moraines, since 

here, as in the other principal canyons of the west 

slope of the Sierra Xevada, there are 110 traces of El 

Portal terminal or recessional moraines. It appears 

that a blunt lobe about 2 miles wide pushed a little 

more than 3 miles, down the canyon to an altitude of 

about 2,600 feet, the lowest point reached by the ice 

in the San Joaquin Basin. Measured from the junction of the Middle and South Fork glaciers to its 

terminus, the San Joaquin trunk glacier was about 

14 miles long.

GLACIERS IN BIG CREEK BASIN«

The Big Creek glacier system wras distinct from 

the great San Joaquiii glacier system. It attained a 

length of about 20 miles and an area! extent of about 

105 square miles. The ice was derived in part from 

cirques at 9,000 to 10,500 feet 011 the south side of 

Kaiser Ridge, but principally from the broad shallow 

cirques situated at about the same altitudes on the 

uplands at the head of Big Creek basin. The ice 

streams converging from these sources coalesced into a 

small trunk glacier wThich pushed several miles down 

Big Creek Canyon, to an altitude of 3,100 feet a 

point almost as low as that reached by the neighboring 

San Joaquin trunk glacier. Thus the terminals of 

the two glacier systems approached each other but 

never united.

North and south of Huntiiigton Lake, older drift 

is plastered against the slopes to heights of several 

hundred feet, except on those steeper places from 

which it has been removed. On the ridge northwest 

and north of Boiieyard Meadow, older drift is present 

to within a few feet of the summit, that is, to altitudes 

over 7,700 feet. Crags on the summit (like those 

shown in figures 36 and 37) clearly show that in places 

rock has been stripped to a depth of 10 feet since the 

passage of the earlier ice; hence the absence of drift 

on some intermediate summits does not necessarily indicate that the ice did not overtop them.

On the trail to Potter Pass, older drift extends up 

to 7,500 feet, and at this altitude the trail crosses a 

distinct morainal ridge which is probably the crest of 

the highest lateral moraine 011 the north side of the 

lake. Xorthwest of Huntiiigton Lake, on the small 

volcano called Black Point, granite boulders are 

within about 400 feet of the top, an altitude probably 

corresponding to the upper limit of the ice. The 

earlier glaciers did not overtop the ridge connecting 

Black Point and Kaiser Ridge. Farther east, the 

lower course of Bear Creek is entrenched in massive 

terraces of the older drift. Still farther east, in the

15 On the glacial map (plate 1), Matthes shows no areas in the 

southeastern part of the Kaiser quadrangle, south of Big Creek Basin, 

as having been covered by ice during the earlier glacial stages, 

though it is reasonable to suppose that older drift probably occurs 

here, as in the upper valley of Dinkey Creek beyond the limits of the 

Wisconsin glaciation. The omission may be due to the fact that this 

region lies mainly outside the San Joaquin Basin, but it may also 

reflect the author's failure to find evidence of pre-Wisconsin glaciation. 

or his inability to carry out the requisite field investigations for lack 

of time.
GLACIATION 53

FIGURE 34. Chiquito Creek basin, north of Placer Ranger Station. 

Typical view of forested slopes covered with drift of the earlier 

glaciation. Smoothly rounded spurs alternate with shallow ravines, 

and no topographic evidences of glaciation remain.

lower valley of the North Fork of Big Creek, a large 

volume of morainal material forms broad terraces on 

both sides of the creek. These terraces slope westward 

toward Huntington Lake, and diminish in height from 

nearly 100 feet to about 50 feet.

Near the mouth of the North Fork, the tunnel of 

the Southern California Edison Company enters the 

mountain at a slight angle to the valley side, and for 

900 feet traverses older moraine, being heavily timbered in this treacherous material. The thickness of 

the moraine against the valley side is estimated at 

close to 100 feet.

Southwest of Huntington Lake, older drift is scattered over the narrow, nearly level spur on which the 

town of Big Creek (altitude 4,500 to 5,000 feet) is 

built. Boulders and cobbles derived from it are used 

extensively to line garden walks. The moraine can be 

traced from Shaver Crossing down the road to Power 

House No. 2.

DEPTH OF CANYON CLTTTINO SINCE EARLIER 

GLACIATION

In a few places, there is evidence that throws light 

on the question of how much canyon cutting has occurred since the earlier glaciers withdrew. One of 

these places is in the basin of Kaiser Creek, north of 

Kaiser Ridge, where older drift forms a discontinuous 

veneer over the undulating slopes on both sides of the 

creek. In this region the stream lies in a small rock 

gorge apparently cut since the earlier glaciation. The 

gorge ranges in depth from about 20 feet, south of 

Mount Tom, to over 50 feet at the place where the 

trail from Potter Pass to Daulton Ranger Station 

crosses the creek.

In the lower part of Chiquito Creek basin, the older 

drift mantles smoothly rounded, gentle slopes and flat 

benches on either side of the stream (page 48). 

Chiquito Creek itself flows through a gorge cut in this 

mature topography. The gorge is about 10 feet deep, 

just above Placer Ranger Station, and over 100 feet 

deep near the mouth of the creek. The gorge is interrupted at Logan Meadow, where, for a section, the 

creek has been prevented from deepening its channel 

due to the massiveiiess of the granite. Relationships 

typical of those found along the Chiquito Creek gorge 

are shown in figure 35.

With reference to the San Joaquin River, similar 

evidence was found in the vicinity of the mouth of 

Chiquito Creek. The lowest occurrence of older drift, 

in place, was found on the north side of the San 

Joaquin channel, at an altitude of 3,250 feet, that is, 300 

feet above the river level. It would appear that at this 

point the maximum depth by which the river could 

have deepened its channel since the earlier ice withdrew 

is 300 feet,

GLACIERS OF THE WISCONSIN STAGE

111 the San Joaquin Basin, as elsewhere in the Sierra 

Nevada during the Wisconsin stage of glaciation, the 

volume of ice was considerably smaller than in the 

earlier stage, and the ice-covered area was, therefore, 

much less extensive. The San Joaquin glacier system 

had, of course, the same general pattern as in the earlier 

stage, for it reoccupied most of the cirques and followed the same valleys and canyons, but it took the 

form of numerous discrete glaciers which became confluent only in part. Accordingly, large upland areas 

which were ice covered in the earlier glaciatiou reFIGURE 35. Gorge of Chiquito Creek, cut into gently sloping valley 

floor cloaked with drift of the earlier glaciation.
54 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

mained bare throughout the Wisconsin stage (figs. 

36, 37).

By far the greater part of the ice which formed in 

the San Joaquin Basin was again part of a bilobate 

system, and this character was the more pronounced 

because the ice was largely confined within the canyons 

or broad valleys. The trunk glacier in the main 

canyon, formed through union of the Middle Fork 

and South Fork glaciers, was only a feeble tongue 

reaching but 2 miles below the junction. The altitude 

at the terminus, the lowest point reached by the Wisconsin ice in this basin, was 3,400 feet. The maximum 

length of the San Joaquin glacier system, measured 

from Muir Pass at the head of the South Fork, was 

47 miles; the length, measured along the Middle 

Fork, was 32 miles.

FIGURE 36. -Residual shafts of type found on Cattle Mountain, between 

junction of Granite Creek and Middle Fork of the San Joaquin 

River, and on other summits (for example around Huntington 

Lake). These summits were overridden by the earlier ice but ever 

since have been subject to disintegration. The shafts are of solid 

granite which has survived the destruction of the jointed granite 

roundabout.

Some glaciers, which in the pre-Wisconsin stages 

were tributary to the San Joaquin glacier system, in 

the Wisconsin stage fell short of joining that system, 

and throughout their existence remained separate ice 

bodies or became confluent only with adjacent glaciers. 

This was the situation with the Granite Creek glacier, 

the Big Creek glacier system, and many smaller 

glaciers on Chiquito Ridge, Kaiser Ridge, and other 

ridges.

MIDDLE FORK GLACIER

Middle Fork glacier was a complexly branching 

body. The main ice stream, in Middle Fork Canyon, 

received tributaries from all of the important branch 

valleys occupied in the earlier glaciation, excepting 

Granite Creek. In their upper reaches (fig-. 38), the 

branch glaciers were largely separated by long ridges

FIGURE 37. Other examples of residual granite shafts of type found 

between Granite Creek and Middle Fork of the San Joaquin River 

(see fig. 36).

of the cleaver type, many of them iiunataks. Conspicuous among these ridges was the narrow crest of 

the Hitter Range, between the upper North Fork and 

the Middle Fork glaciers. At the south, the rather 

similar Silver Divide parted the sources of Fish Creek 

glacier from glaciers of the South Fork system. 

Downstream, the branch glaciers were channelized

FIGURE 38. Lower end of Thousand Island Lake, in cirque at head of 

the Middle Fork of the San Joaquin River; Banner Peak in the 

background. The ice-smoothed ledges of quartzite are breaking up 

by opening of joint cracks.
GLACIATION 55

within the gorges into relatively narrow but deep ice 

streams. The lower courses of the North Fork, South 

Fork, and Fish Creek glaciers swept around and 

isolated several broad upland tracts which the earlier 

ice had overridden, for example that platform extending from the Granite Stairway to Lions Point. The 

ice reached a depth of more than 2,500 feet at the 

junction of the North and Middle Forks. Balloon 

Dome was a nunatak, the ice of this stage rising to a 

level of 1.500 feet above its base but never overwhelming the summit.

The North Fork glacier received a large branch from 

the valley of what is now the East Fork of Granite 

Creek. The East Fork glacier bifurcated, one very 

small lobe extending southward across a low divide into 

the Granite Creek basin, where, at Soldier Meadow, 

it just reached but failed to join the glacier of that 

basin. During deglaciation, the disappearance of this 

small lobe permitted the rearrangement of drainage 

whereby a stream previously tributary to the North 

Fork of the San Joaquin River was diverted across the 

low divide and became the present East Fork of Granite 

Creek.

SOUTH FORK GLACIER

The glacier system in the basin of South Fork was 

larger and more complex than that in the basin of 

Middle Fork. Its maze of ramifying sources was 

incompletely denned by the winding, branching crests 

of Mono Divide, Glacier Divide, Goddard Divide, Le 

Conte Divide, the Silver Divide, and other ridges 

(fig. 39). Some of the small glaciers on the south 

side of the Silver Divide and on the north side of the 

Kaiser Ridge joined the South Fork system.

RE 39. Cirque northwest of Selden Pass showing fine development of a "sapline." with spintered cliff above and corraded slope 

below. The moraine loop (double-crested) in the foreground, traversed by the trail from the South Fork of Bear Creek to the South 

Fork of the San Joaquin River, probably was formed in historic 

time.

FIGURE 40. Typical rodies moutonnees, upper end of the Blaney 

Meadows, in the valley of the South Fork of the San Joaquin River. 

The ice movement was from left to right. Photograph by G. K. 

Gilbert.

The trunk glacier, although the product of many 

large, convergent ice streams, was relatively unimpressive. For a number of miles it did occupy the full 

width of the broad upper valley of the South Fork 

(fig. 40), and below the junction of the Mono Creek 

branch the ice was more than 5 miles wide and 1,500 

to 2,000 feet deep; but farther downstream it dwindled 

to a narrow ice tongue which, northeast of Hoffman 

Meadow, was entirely confined within the inner gorge, 

here only i/2 to 1 mile wide and about 1,500 feet deep. 

At its junction with the Middle Fork glacier, the 

South Fork glacier had much the lesser volume of the 

two branches.

At Selden Pass, striae and chatter marks on the 

bedrock show that ice from the head of Bear Creek 

basin moved southward into the South Fork system. 

Evidently the ice in Bear Creek basin was much higher 

than that in the South Fork.

During deglaciation, the Mono Creek glacier, following its separation from the main trunk glacier in the 

valley of the South Fork, left a remarkable series of 

seven creacentic frontal moraines at the lower end of 

Vermilion Valley (fig. 41). These ridges enclose a 

3-mile long meadow, and the swales between them 

also are occupied by narrow strips of meadowland. 

Traced up the south side of Vermilion Valley they 

unite into several straight lateral moraines extending 

for about ~2 miles.

In investigating potential dam sites, the Southern 

California Edison Company in 1924 drilled a series 

of eight test holes in this area of frontal moraines. 

The line of holes apparently began near the axis of the 

valley and extended east-northeast in a nearly straight 

line across the remainder of the valley. The eight 

holes penetrated, respectively, 180, 116, 77, 74, 62, 25, 5,
56 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

FIGURE 41. -Moraine of the later glaciation, one of the series deposited 

by the Mono Creek glacier ill the lower part of Vermilion Valley. 

The direction of ice movement was left to right. Photograph by 

G. K. Gilbert.

and 2 feet of unconsolidated material, including boulders, gravel, and sand, probably both glacial and 

glaciofluviatile material older than the Wisconsin as 

well as of Wisconsin age. The hole nearest the axis 

of the valley was still in unconsolidated material at 

the 180-foot depth (written communication, T). H. 

Redinger September 15, 1924).

Immediately east of Vermilion Valley, and at 

levels 1,500 feet or more above its floor, is another 

series of moraines, disposed in a fan shape. They 

converge eastward, and across the divide between Mono 

Creek and Bear Creek they unite to form lateral 

moraines on the north side of Bear Creek valley. 

These moraines graphically record the fact that the 

Bear Creek glacier, on rounding the great right-angled 

bend in its valley, at higher stages overrode the crest of 

Bear Ridge to the north and contributed ice to the 

Mono Creek glacier.

West of Vermilion Valley is a third cluster of 

moraines (fig. 42) : a concentric system of large, curving ridges, the convex sides of which are directed 

northeastward up the valley of Mono Creek rather 

than down it, as in the case of the much smaller Vermilion Valley moraines. These moraines are now 

deeply notched by Mono Creek (fig. 43). They are the 

right lateral moraines of the South Fork glacier, and 

mark the successive borders of the ice which, following the separation of the trunk glacier and the Mono 

Creek branch, for a time bulged a short distance into 

the newly evacuated lower Mono Creek valley (fig. 44).

Prominent and almost continuous lateral moraines 

define the upper levels of the South Fork trunk glacier.

FIGURE 42. \Vell-developed lateral moraine of the later glaciation, 

deposited by the glacier which occupied the valley of the South 

Fork of the San Joaquin River. Near the mouth of Vermilion 

Valley.

FIGURE 43. View eastward up th? glacially modified canyon of Mono 

Creek. The high hanging valley on the right is the First Recess, 

and beyond it appear the entrances to the other hanging canyons 

known as the Second. Third, and Fourth Recesses. At the right is 

si "Kapline" with frost-riven cliffs above and slopes of exfoliating 

granite and talus below. Photograph by G. K. Gilbert.

East of Hoffman Meadow are several parallel moraines 

with definite crests. The highest moraines, traced 

north-northwestward, end on a spur at the edge of the 

San Joaquin Canyon, at an altitude of 6,600 feet, east 

of the mouth of a hanging valley. These moraines in 

places follow ridges of granite, but on the whole they 

are laid irregularly, cutting across the drainage lines 

and ridges at an angle. In several places an indistinct 

moraine was found just outside the main Wisconsin 

moraine, and in general parallel to it, suggesting the 

record of an early maximum of Wisconsin glaciation, 

similar to the record on both sides of the Little Yosemite Valley (Matthes, 1930a, p. 58-61).

At the junction of the Middle and South Forks, the 

uppermost lateral moraine on the north side of the 

South Fork is unmistakable although it is not strong.
GLACIATION 57

FIGURE 44. - Mono Meadow, one of the many meadows characteristic 

of the rough, unequally glaciated floor of the valley of the South 

Fork, San Joaquin River.

It meets the multiple lateral moraine of the Middle 

Fork at an altitude of 6,UOO feet above Rattlesnake 

Lake.

GLACIERS ON KAISER RIDGE

Eastward-trending Kaiser Ridge presents an interesting contrast in that it has been severely glaciated 

on the north side and only mildly on the south side.

Glaciers of the south side were relatively small, 

separate ice bodies. One of the larger ones headed 

on Kaiser Peak, altitude 10,300 feet, and occupied the 

valley between Bear and Line Creeks. This glacier 

was 2y2 miles long and descended to 7,400 feet. Its 

lower positions are indicated by conspicuous loops of 

moraine, and similar loops define the limits of the 

smaller Deer Creek, Line Creek, and Home Camp 

Creek glaciers. Nellie Lake, which lies in a cirque 

without headwall, although surrounded by mountains 

of moderate declivity, is impounded by a strong 

moraine dam, outside of which, on somewhat lowrer 

ground, is another much larger and higher morainal 

embankment.

About 2 miles east of Kaiser Pass, a narrow ice 

tongue originating at about 10,000 feet descended low 

enough to coalesce, in part, with the Big Creek glacier. 

Its terminal portion pushed westward across a divide 

into the valley of the North Fork of Big Creek, which 

was ice free. This glacier reached a length of 3y2 

miles and a lower limit of 7,700 feet. It left a complex

of moraines, some of which border Badger Flats. 

Other moraines, including the right laterals of the Big 

Creek glacier, have effected the diversion of a stream 

in the upper valley of Big Creek to the drainage of the 

North Fork. The trail, which goes south from Badger 

Flats, passes through the part of the lower valley left 

streamless by this diversion.

Still farther east on Kaiser Ridge, broad shallow 

cirques at 10,000 to 10,500 feet contributed ice to the 

Big Creek glacier, by \vay of the valley of the East 

Fork.

On the north side of Kaiser Ridge lay a rank of 

glaciers that coalesced, along the crestal part of the 

range, into an almost continuous mantle of ice. At 

lower altitudes these glaciers, 2 to 4 miles in length, 

separated into individual lobes, which terminated in 

valleys on the upland, at altitudes of 7,400 to 4,100 feet. 

In the eastern part of the range, the glaciers joined the 

South Fork trunk glacier, at altitudes of 7,500 to 8,500 

feet. The lateral moraines of the trunk glacier cut 

straight across the lower valleys of Kaiser Ridge, 

marking the well-defined level at which the lateral 

moraines of the tributary glaciers on Kaiser Ridge 

abruptly terminate.

The largest glacier on the north side of Kaiser Ridge 

occupied Kaiser Creek valley. It headed in a series 

of cirques stretching for 5 miles along the crest of 

Kaiser Ridge, south of Kaiser Peak Meadows. The 

ice descended to an altitude of 7,100 feet, about % 

mile below Sample Meadow. This glacier left an exceptionally fine morainic record, its recessional moraines marking stages not only in the shrinkage of the 

confluent ice body but also in the final dwindling of 

the little individual glaciers into which it eventually 

separated. That the Kaiser Creek glacier at one time 

was voluminous enough to spill over the saddle east of 

Sample Meadow, and thus joined the San Joaquin 

trunk glacier, is attested by the prominent ridges of 

moraine that descend from the hill to the southeast of 

the saddle.

Outside the prominent outer morainic loop of the 

Kaiser Creek glacier is another loop consisting of 

isolated boulders 50 to 100 feet apart. This loop 

appears to be an older moraine from which the finer 

material has been washed away. Yet this moraine is 

not comparable in age to the moraines of the earlier 

glacial stage, for its boulders rest on ground resembling 

that occupied by the younger moraine, that is, ground 

which has not disintegrated deeply enough to produce pinnacles and crags, but \vhich still shows the 

smoothing effects of ice. This moraine therefore 

properly may be regarded as representing early Wis-
58 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

consin time. It is analagous to similar moraines 

noted in various places in the Yosemite region.

At Twin Lakes, east of Kaiser Peak, some of the 

granite erratics of the Wisconsin stage that rest on 

limestone bedrock have become perched on pedestals, 

due to relatively rapid reduction of the surface of the 

limestone by solution and frost action (fig. 45). One 

boulder 5 feet high and 7 feet long stands on an 

8-foot pedestal.

GRANITE CREEK GLACIER

The glacier which occupied the Granite Creek basin 

during the Wisconsin stage, and which throughout its 

existence remained separate from the Middle Fork 

glacier, was fed from sources mostly situated along 

the east side of the crest extending southward from 

Triple Divide Peak, at altitudes of 9,000 to 11,000 

feet. These sources formed a continuous gathering 

field which from north to south was almost 8 miles 

across. The lower part of the glacier was a blunt 

lobe which lay about a mile southeast of the Clover 

Meadow Ranger Station, at an altitude of 6,900 feet. 

From its source on Triple Divide Peak to this terminus 

the glacier was 9 miles long. Multiple-crested moraines of this glacier are prominent south of Clover 

Meadow and in the vicinity of Soldier Meadow.

FIGURE 45. Erratic boulder of granite on a low pedestal of crystalline 

limestone, near Twin Lakes east of Kaiser Peak. As a rule, boulders 

of the later glaciation do not have pedestals, but here the bedrock, 

being limestone, has been reduced at a relatively rapid rate. Nearby, 

another erratic 5 feet high and 7 feet long stands on a limestone 

pedestal 8 feet high.

FIGURE 46. Glacial erratic on floor of Mono Creek Canyon, below First 

Recess. Photograph by G. K. Gilbert.

GLACIERS IN CHIQUITO CREEK BASIN

As in the earlier glaciation, Chiquito Ridge developed 

glaciers only on its northeast side, where they were 

small, separate ice bodies. Several of these, all cirque 

glaciers, were clustered on the east and northeast sides 

of Shuteye Peak, altitude 8,858 feet; three additional 

slightly larger glaciers, each about 2 miles long, 

formed farther to the northwest at altitudes of about 

8,000 feet, between Little Shuteye Peak and Texas 

Flat. The lower ends of these glaciers lay at altitudes 

of 6,850 to 5,700 feet.

Small glaciers also formed in the extreme head of 

the basin, on Redtop Mountain and Sing Peak, at 

altitudes of about 10,000 feet; and ice confluent with 

the Merced glacier flowed 1 or 2 miles into Chiquito 

Creek basin, where it left beautiful loops of moraine 

just south of Chiquito Pass. These moraines are 

crossed by the trail through the pass.

GLACIERS IN THE BIG CREEK BASIN

In the Wisconsin stage, glaciers again descended the 

tributary valleys of Big Creek, but the trunk glacier 

they produced was small and remained separate from 

the little glaciers on the central and western parts of 

Kaiser Ridge. In fact, the glacier in the branch 

valley of Tamarack Creek failed to unite with its 

neighbor in the East and South Fork branches of Big 

Creek valley, though at their sources the ice bodies 

in places were confluent. The Tamarack Creek glacier 

was 5 miles long and descended to an altitude of 7,400 

feet. The Big Creek glacier was over 10 miles long, 

following the East Fork, and descended to 6,900 feet. 

Its terminus was approximately in the middle of 

Huntington Lake.

In the headwater region of these glaciers, a number 

of hills and ridges over 9,500 feet high, including Black 

Peak (fig. 47), were nunataks. Here the upland to-
GLACIATION 59

FIGURE 47. Black Peak, a volcanic knob situated near the head of 

the South Fork of Big Creek ; in the foreground, Long Meadow. The 

angular blocks of granite in the meadow were dropped by a glacier 

of the later stage which filled the meadow to within a few hundred 

feet of the top of Black Peak. Photograph by G. K. Gilbert.

has been only slightly modified by glaciation, 

but it is littered with drift. Long Meadow is truly 

a "moraine meadow'' and with its many scattered granite blocks it presents a peculiar aspect (figs. 47, 48). 

Moraine ridges, 10 to 20 feet high, are locally conspicuous.

The lower limits of the Big Creek and Tamarack 

Creek glaciers are marked by conspicuous moraines. 

The right lateral moraines of the Big Creek Glacier 

extend westward from the base of Bear Butte. Near 

Huntington Lake they deplcty northward to the mouth 

of the North Fork of Big Creek, then again run westward as low, rock-crowned embankments along the 

north shore of the lake. They decline in height very 

gradually to a point just west of Bear Creek, where 

they disappear beneath the lake. The left lateral 

moraines are massive embankments which flank the 

north base of Chinese Peak. They continue northwestward to the south shore of the lake, obstructing

FIGURE 48. View from the summit of Black Peak (see fig. 47) looking 

down the length of Long Meadow (altitude 9,000 feet). Long 

Meadow is typical of the many large upland meadows of the San 

Joaquin Basin.

southward drainage and giving rise to a large wet 

meadow. Finally they dip into the lake at the end of 

a rocky promontory about 1 mile west of the mouth 

of Big Creek. Small rocky islands near the lakeshore carry glacial boulders, and a long line of boulders 

protruding from the lake near its end, marks the crest 

of a drowned moraine.

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60 GEOMORPHOLOGY AND GLACIAL GEOLOGY OF THE SAN JOAQUIN BASIN, CALIFORNIA

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INDEX

A. Page

Abies concolor ______ __ _ _ . ___ _ __ 11

Acknowledgments____________________ _____ G

Agnew Meadows, ______________________ _____ 27

Agnew Pass. ________ _______________ __ _ 5,18, 27, 39

Alabama Hills__ ____ _______________ __ _____ 6

Andesitic flows. ________________ ________ ____ 18

Anticlines.. ______ ________________ ___________ 17

Arctostaphylos _ _-- - 11

Area of report, geographic sketch _____ _ _____ 6-13

location and extent _______________ __ 6-8

B 

Bald Mountain, _____________________ ___ 15-16.33

Balloon Dome__--_______________________ 15,16,27,55

Basalt-____ __________________ ___________ __ 5,12,18

Basins, drainage____________________________ _ 21

Bear Creek glacier. __________________________ 51

Benches____________________________________ 40

Big Creek__________________________________ 8,32

Big Creek Basin_____________________________. 19

glaciers in___________________________ 52-53,58-59

Big Creek Post Office_-_---___________-_ ____ 26

Big Sandy Bluffs____ ________________________ 33

Big Sandy Creek______________ ___ _______ 8,32

Bismuth. ____________________________________ 12

Black Peak_____-__--_-__-_-_-_--____-_____ 19,58,59

Black Mountain _____________________________ 24

BlackPoint - __ - 19,52

Blaney Meadows___________ _________________ 29.55

Boulder, perched_____________________________ 58

Brown Cone___--_--_--_-____ __________ 19

Burro (Burrough) Mountain_________________ 33

Buttermilk Country -_____________________ 39

Canyon cutting, depth since earlier glaciation_ 53

Capture, Stevenson Creek_-_____-____________ 45

Cascada Station_________________.____________ 26,31

Cathedral Peak granite-__--__----___---___ __ 13

Cathedral Range__________-_____-____________ 35

Cattle Mountain_____________________________ 13.54

Chinese Peak------____-_--__-----__ ________ 19

Chiquito Basin_ _ _________________________ 5

Chiquito Creek..--.____- ---_ -__- 8,53

Chiquito Creek basin__--_.___________ ______ 5,53

glaciersin..___ _________ ______________ 58

Chiquito Creek glacier.______________________ 51

Chiquito Ridge______________________________ 15,35

Cirques.... _- _ __-__-__- __- 34,46,57

Climate.._______________________ _ .___ _- 9-11

Clover Meadow. _________________ ___________ 5

Ranger Statiou___________________________ 18, 58

Cobbles, glacially striated____________________ 51

Cones, volcanic_____________________________ 19

C opper_ _ __.-.__-.___-___---_-_---__------_._- 12

Crane Valley Lake-___-_-_____-___--___-___- 12

Crater Creek______________-__________-_-.__._ 32

Crests, longitudinal and transverse_---_____ _ 34-38

D

Dana-Minarets Wild area__________________ _ 12

Daulton Ranger Station _____________________ 5

Desolation Lake____________________________ 30

Devils Postpile National Monument. 5,12,18, 27 

Diversion, East Fork of Granite Creek._ ._ _ 42,55 

Domes______ -____-_ --_--___ _____ ____ 15,16,31

Drainage___________________._-_____ ______ 8-9,20

Drainage divide, main.--._,__--__-- _____ __ 38-39

Drainage pattern, evolution of . __________ 23-24, 45

Drilling, as part of investigation for potential

dam sites.___--___-____ -_ _ 55-56

E Page 

Economic use of SanJoaquin Basin__________ 12-13

ElectraPeak... _____________________________ 28

Emerald Peak _______ _______________________ 37

Erosion... _ __________ ___ ___ 20

surfaces_____ _______ _____________________ 40-41

Escarpment, eastern. _ _ _ _____ _____________ 39,45

Evolution Basin____ _____________ _____ 29,38,47,48

Evolution Creek __ _____ ___________________ 29

Evolution glacier. ____________________________ 50

Evolution peaks, group of. _____ _______ _____ 13,29

Evolution Valley_---_____-____ ________ 29,30,34,47

Exfoliation ___________________________________ 15

Expeditions, itinerary of. . _ ___________ _____ 5

F

8,27

28

50

43

29

Fish Creek._--__--____ __________________

Fish Creek Canyon ____ ________________

Fish Creek glacier_____ _-._._. __. _

Fish Valley . .__ __ ___________ _____

Florence Lake ___________________________

Foothill belt ________________________ 5,17,18.24-25

Fossils ___________ ___________________ 21.23

Four Forks Creek-._ - _- ___________ 32

French Canyon______________________________ 29

Fresno Grove -_ _-- __- _ _ -- 11 

Fresno River. _ _ _ ___________________________ 6

Friaiit_ __ ________________________________ 8,12

Friant Dam______________ _____ _____________ 12

G 

Gale Peak . _________________________________ 37

Geomorphologic features, interpretation. 38-46 

Glacial drift..___ ___________________ _____ 51,52,53

Glacial stages, correlation_____ ___ ______ _ 48-49

Glaciation -_________ ______________________ 46-59

Glacier Divide._---____-_____ ___ ___________ 35

Glacier Point stage.___________ ____ _________ 49

Glaciers, existing..._______________________ __ 35

Goddard Canyon 29,37

Goddard Canyon glacier. __________ _________ 50

Goddard Divide..____________________________ 17,37

Granite. .- 13-17

Granite Creek . __-__ _ ______-_-_---__- 8,42

Granite Creek glacier, of Wisconsin stage. __ _ 58 

Granitic, defned.- ____-________ _ _-_-- _ 13

Gravels, fossil-bearing.___________ ___________ 21

Great Valley of California,___________________ 9

Great Western Divide________________ _ ___ 21

H

Hanging valleys. - __ 8, 22-23,30-32, 47 

Hetch Hetchy Valley...__---_-_ .. ____-_ 21

High Sierra- _--__---_-__-_--- 8,9,10,11,12,34-38 

HoflmanCreek__-__ -__ __ - __- 32 

HofEman Meadows,______ - _- 29

Hot Spring Peak-..____ _______ _____________ 37

Hudsonian life zone_____ ___________________ 11

Humphreys Basin__________________________ 30

Huntington Lake.__________-____-_-__--___- 10,12

Huntington Lake reservoir,____ _____________ 12

Huntington Lake State Game Refuge. -- 12

I 

Icefield, central __ _________________ _____ 51-52

Introduction.____ _ _______ __ _-_---___- 3-6

Investigations, subsequent to fleldwork_____ __ 5-6

Irori_ __ __ _ _____--_-__-----_-___-- 12

Iron Mountain_______

Irrigation. ____________

Itinerary, expeditions.

J Page 

Jackass Creek._.._____ _.__ _________________ 8,34

Jackass Dike____-____--__-_------_-_-___-__._ 29

Jackass Rock _ - - 31

John Muir Trail________--____-__-_________- 12,37,38

Jointing._____________________________________ 15,45

Jose Basin.__________________________________ 26

glaciers on__ _____________________________ 57-58

Kaweah River _ _____

Kerckhoff Dome _.___ 

KerckhofE Lake ______

Kern Basin____________

Kern Canyon _________

__________________ 21

____--___-_--__-_ 15

_________________ 12

__________--.___- 20

_________________ 20

_________________-____-__-_--__-_- 29-21

King Creek---- -_ -- - 8

Kings Canyon National Park___---_-_______- 12, 15

Kings River.. - - 21

Lake Florence reservoir.. _____________________ 12

Lake Thomas A. Edison______________-__--_- 5

Lead... ___________________-__--__--__--____- 12

LeConte Divide-_-___._------_----_------_- 17

Libocedrus decurrens-.------------------------ 11

Life zones...-. -_- - -_ - - - 11-12 

Location of report area_ ___--__-_--__--_-_-__- 6-8

Long Meadow____________________________ 34, 59

M

McKinley (Dinkey) Grove_-__-_-___-__---__- 11 

Madera Peak --___-----------------_--- 37

Magnetite ,-- - -- - - 13 

Mammoth Mountain.__.__---____-_-.-__- 9,18,39

Mammoth Pass--.____ __._-____-____-__ 9,18.34,38

Maps, of Sierra National Forest. _____________ 12

Mariposa Grove..____________________________ 11

Martha Lake___ _____________________________ 29

Merc°d River.-____-_-------_-------------- 21,23

Middle Fork, of San Joaquin River. _________ 8, 27

Middle Fork glacier..___________--_---__---__ 50

Middle Kern Basin. __. ___ _________________ 6

Millerton Lake _--__--_--- -------____-- 12

Minaret Creek...- - - - -_ - - 8 

Minaret mining district.-..------.----------- 12-13

Minaret Pass__--__- ___ -__--_ 9,34,38 

Minarets. - - 28,35

Mineralization, in the Minaret mining district - - - 12-13 

Molybdenum-----.- --------------------- 12

Mono Creek ------------------------- 29,56

Mono Creek glacier- ___________ _______ 51,55,56

Mono Lake. _____________ -__ _ - __ 6

MonoMesa__ _______-__-_______-___---_---__ 38

Moraines._ ___._-_-_------_-------_---_------- 16,

46,47, 48-49, 53,55,56, 57, 58,59 

Mother Lode system.._____________________ 17

Mount Dar_.in______--___--__--_-_-_---__- 29,38,41

Mount Davis____ _ ___ _______--_____-__---- 28

Mount Goddard.-__---_--.----- _-__ 37

Mount Hooper, ____.__________- __-___-- 37

Mount Humphreys-____------------_----_-_- 8,39

Mount Lyell--- -- _---- - 35

Mount McGee.-.-_---_----------- --- 37

Mount Raymond---------------------------- 35

Mount Relnstein___--___--- -_ --_ 37 

Mount Senger___ __ ___--_-_-_---_---_--__--- 37

Mount Stevenson.___-__--__-___-___---_---__ 20

61
62 INDEX

Mount Tom. _ __ __ ___ _ ___ 34 

Mount Wallace...________________ 38,41

Mount Whitney____________________ 35,38

Muir Pass_________________...___ 29,37

Music Peak.._______________ ________ 26

Nellie Lake__.________________________ 57

North Fork, of San Joaquin River.___________ 8

North Fork Canyon______________________ 28

Nunataks_________________________________ 52,55,58

O 

Oat Mountain..._____________________________ 26

Owens Mountain______________ ____________ 24-25

Pavilion Dome_

Pine Ridge_____

Pinus albicaulisjeffreyi... ...

monticola.--- 

murrayana--- 

ponderosa _ _

____________________ 15

_ _________________ 32

____________________ 11

____________________ 11

___-______________ _ 11

________ _ ____ 11

________ _ _________ 11

__________ 11

__. ______________ __ 11

_______________ _ __ 34

___ _ ______________ 29

__________________ 50

. _ .___ _ _ _ 38

Placer Ranger Station _ _______ _ ___________ 5,53

Potter Pass, trail to.___ __ _ _ __________ _ 52

Precipitation. _____ _ _____ __ ____ _ _____ _ 9, 10

Profiles, restored Miocene and Pliocene____ _ 41-44

Pseudotsuga tarifolia ________ _ _______________ 11

Pumice. __ _ __ _ _ ___ _____ _ _ ._ __ 19,39

Pumice Butte____________________ _ _________ 18

Pumice Flat______ __ _ _ ___ _ _ ____ ______ 8,27

R

Railroad, San Joaquin and Eastern narrowgage-. _______ ____________________ 26

Pioneer Basin______

Piute Canyon ____

Piute Creek glacier. 

Piute Pass. __ _

Page 

Rainbow Falls.- __ -______ ___ ___ _ 18,19,27

Ranger Station, Clover Meadow___ __________ 18,58

Daulton___ __ ___________________________ 5

Placer-.- _______________________________ 5,19,53

Rattlesnake Creek____ _ _ __ ._ ___ _ _ _. 32

RedCones___ _______________ 18

Red Mountain... ____________________________ 19,37

Reds Meadow _ _____________________ _ __ _ 5, 18

References, selected_-_.__-_ _ __-__ _ ..___ _ 59-60

Ridges, signlfi cance of pattern of ______________ 44-45

Ritter Range___________________ 9, 12, 28, 35,39, 44, 45

Rock Creek.. -----___----_ --------- 8,32

Rock Meadow _.--____----____-_-__-_-_ ____ 34

Rocks..- - - _ _ 13-19 

Round Mountain. ________-.___-----__ _ ____ 24

Rube Creek.. --_____------ -----_---- 32

Rush Creek Basin_______________-_____-_-____ 39

S

San Joaquin Canyon and its main branches _ 25-30 

San Joaquin glacier, lower____________________ 52

San Joaquin River_ __________________ 3,22,25,26,45

Selden Pass 

Sequoia gigantea __ ___

"77" Corral _ __ _ ____

Shakeflat Creek. ______

Shaver, Calif. __ 

Shaver Lake ____ __ 

Shaver Lake reservoir_ 

Sierra National Forest

Silver Creek __ _______________ _ _. _______ __ 8

Sing Peak- __________________________________ 37,58

Snowfall.... ---___----_- ---__-____--__- 10-11

Social use, of San Joaquin Basin_.____________ 12-13

South Fork, of San Joaquin River__________ 8,32,34

South Fork Bluffs.. _- ___- _- 33

South Fork glacier.... ________________________ 50-51

of Wisconsin stage____ _ _____ _ ______ _ 55-57

Squaw Dome_____________-__-____- _ ________ 15, 18

Stairway Creek.. _____ ___ _____ __ _________ 32

Page

Stevenson Creek____-____ -___ -_--___- 8,32,40

Summits, tabular___________ ____________ 24,38,41

Synclines___ ___________________________ 17

Table Mountain._______________________ 19, 21, 23, 25

Tamarack Creek__-__--__________________ 8

Tarns. ____-_ ____________ ________________ 30

Tehachapi Pass______________________________ 20

Terraces_____--___-_--______-____________ 53

Thousand Island Lake.____________ 5,27,34,54

Topography ______________________________ 8-9

Transition life zone_____________________ 11

Tsuga TOe. l?ens.ffna__ __________________________ 11

Tungsten.______________________ ___ 12

Tungsten Hills._____________..____._ 39

Tuolumne Basin.--__-_-_-___________-.___. 21

Tuolumne Glacier.._._. ____________________ 47

TwinLakes___-_____________ _____________ 18,37,58

Uplands, intercanyon . __ _ __ 8-9, 23,33-34, 40-41 

Upper Sonoran life zone._____________________ 11

V 

Valleys, hanging _________________________ 30-32

significance of pattern of..____________ 44-45

Vegetation. ______________________________ 11-12

Vermilion Valley.-___-__-___-__--_________- 5,55, 56

Volcanic Knob- ------------ -------_--___- 19

W 

Warm Creek Meadow________________ 34

Weathering, modes of ______________________ 15-17

White Divide._______________________________ 37

Willow Creek---.------------------ 8

Wisconsin stage, glaciers of_.._-________.___._ 53-59

Y

Y osemite region, summary of conclusions..... 22-24 

Z

Zinc_ 12

O