Pre-Wisconsin Soil in the 

Rocky Mountain Region 

a Progress Report

GEOLOGICAL SURVEY PROFESSIONAL PAPER 221-G
Pre-Wisconsin Soil in the 

Rocky Mountain Region 

a Progress Report

By CHARLES B. HUNT and V. P. SOKOLOFF

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1949, PAGES 109-123

GEOLOGICAL SURVEY PROFESSIONAL PAPER 221-G

A study of ancient soils in the 

Lake Bonneville and Denver Basins

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 19SO
UNITED STATES DEPARTMENT OF THE INTERIOR

Oscar L. Chapman, Secretary

GEOLOGICAL SURVEY

W. E. Wrather, Director

For sale by the Superintendent of Documents, U. S. Government Printing Office 

Washington 25, D. C. - Price IS cents (paper cover)
CONTENTS

Abstract____________________________________________________________________________________________________ 109

Introduction ______________________________________________________________________________ _^ _________________ 109

Paleopedology_ _--_----__---_-_-________-___-_-_______---_____________________________________-__-___________ 109

General background _______________________________________________________________________________________ 109

Soil age_________________________________________________________________________________________________ 109

Paleosol in the Rocky Mountain region___________________________________________________________________________ 111

Geographic extent_________________________________________________________________________________________ Ill

Parent materials.__________________________________________________________________________________________ 111

Clay layer._______________________________________________________________________________________________ 111

Lime-enriched layer.__-___--_-_________--_--_________--___________--__-__--__-_-____________-____--_-______ 114

Age of the paleosol_____________________________________________________________________________________________ 114

Stratigraphic evidence in the Lake Bonneville Basin_____-______________-____________--_________________________ 114

Stratigraphic evidence in the Denver Basin.__________________________________________________________________ 115

Topographic evidence______________________________________________________________________________________ 116

Difference between the paleosol and the Wisconsin or younger soils_-__--__-_-___________-_---_____-__--____________- 116

Some problems in identifying remnants of the paleosol___________________--____________----_-__-____--_--_-_______- 117

Origin of the paleosol and its bearing on Pleistocene history_______________-__________-_-_----__--____-_--_________- 117

Partial bibliography___________________________________________________________________________________________ 118

Index. ________________________________________________-_________-___--_______--__-____-_-.-_ 123

ILLUSTRATIONS

Page 

FIGURE 10. Diagrammatic profile of pre-Wisconsin soil, or paleosol, in the Rocky Mountain region______________________ 110

11. Localities in Utah, Colorado, and New Mexico where pre-Wisconsin soil has been identified-__-__---________ 112

12. Diagrammatic cross section illustrating some relationships between the geology and soil development in the

Lake Bonneville Basin, Utah_____________________________________________________________________ 115

13. Diagrammatic cross section illustrating topographic and Stratigraphic relations of the paleosol in the Denver

Basin, Colo____-_____________-_______________--__________-____---_____--_-__-_--__-----_------__- 115

in

PRE-WISCONSIN SOIL IN THE ROCKY MOUNTAIN REGION, A PROGRESS REPORT

By CHARLES B. HUNT and V. P. SOKOLOFF

ABSTRACT

An ancient soil (paleosol) dated, from its stratigraphic relations, as pre-Wisconsin in the Lake Bonneville and Denver 

Basins, consists of a few feet of red-brown leached clay overlying several feet of lime-enriched weathered parent material. 

The soil has been found on many kinds of parent material, in 

many topographic positions, and at altitudes ranging from 

5,000 to more than 8,500 feet. Like the rather similar gumbotils in the Middle West the paleosol in the Rocky Mountain 

region is useful for distinguishing late Pleistocene and Recent 

features from earlier ones. Further study of paleosols offers 

promise of furnishing much additional information about soil 

genesis problems and providing increasingly refined means for 

distinguishing between Pleistocene features of different age.

INTRODUCTION

An ancient soil, hereafter referred to as paleosol, has 

been dated, from its stratigraphic relations, as preWisconsin in the Lake Bonneville and Denver Basins. 

It has been identified tentatively in other parts of the 

West. This paleosol offers promise of becoming an 

important means of distinguishing early Pleistocene 

features from late ones in those parts of the Rocky 

Mountain region that are remote from known Pleistocene glacial or lacustrine deposits.

The paleosol was first recognized in 1947 in Utah 

Valley, Utah, during a survey and restudy of the Lake 

Bonneville Basin that has been started by the United 

States Geological Survey. More recently the paleosol 

has been recognized and considerable areas of it mapped 

in the Denver Basin, Colo.

In developing the evidence that is presented herein 

and in the preparation of this report we have had the 

valuable assistance of numerous soil scientists in the 

Division of Soil Survey, United States Department of 

Agriculture. James Thorp, Ray C. Roberts, and C. C. 

Nikiforoff were especially helpful. Thorp and Roberts, accompanied by other members of the Soil Survey 

and soil scientists of the Utah State Agricultural 

School, visited the senior author in Utah Valley in 

1947 and examined some of the paleosol localities in 

that area.

In 1946, before the paleosol was recognized, the senior 

author, who was then mapping Utah Valley, was visited 

by Dr. Geoffrey B. Bodman of the Division of Soil 

Survey, University of California. It was very largely 

through Dr. Bodman's guidance and encouragement 

during the early phases of the field work that the paleosol was first recognized.

Special acknowledgment is due also to Charles S. 

Denny of the Geological Survey for his thoughtful and 

critical review of the manuscript.

If this report contains a contribution to geology and 

soil science, perhaps its greatest value will be to encourage more complete and more widespread cooperation between soil scientists and geologists. The kind 

of problem that is under consideration is only a sample 

of many that require the attention of both.

PALEOPEDOLOGY

GENERAL BACKGROUND

Paleopedology, the study of ancient soils, was begun 

in the second half of the last century, chiefly in Russia 

and particularly in the Ukraine, where numerous buried 

soil profiles are interbedded with loess deposits of different age. Ruprecht (1866) appears to have been one 

of the first to recognize the existence of paleosol, its 

bearing on the problems of pedogenesis, and the problem of pedologic and chronologic age of buried soils.

Many American geologists have recognized the 

weathered zones between the sheets of glacial drift in 

the middle western States, but Kay and Pearce (1920) 

seem to have been the first to study the weathered zones 

as profiles of old soils.

A partial bibliography of papers that contain descriptions of or references to paleosols is given at the 

end of this report.

Stratigraphically identifiable paleosols, common as 

they are, particularly in the formerly glaciated areas, 

constitute but a small proportion of the total. Actually, considerable parts of the soils and soil materials 

in the regolith are probably paleosols in the sense that 

they represent effects of ancient rather than modern 

environments on the parent rock. The cumulative 

effects represented are so complex, however, as to make 

it impossible, in the present state of our knowledge, to 

separate the successions of environments on the sole 

basis of the end product. Only simple cases can be 

recognized and interpreted.

SOIL AGE

Age of soil, that is, of the soil profile, can be considered under two categories chronologic or absolute 

age and pedologic age. The two are quite different.

109
110 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1949

Chronologic or absolute age involves the length of 

time during which a soil may have been forming and 

the geologic or historic date of the event. In this paper 

we are concerned primarily with the geologic age of 

the paleosol.

The concept of pedologic age, which deals with the 

relative maturity of the soil profile, needs a great deal 

more study in order to be useful in problems pertaining 

to chronologic age.

Following Mohr (19M), pedologic age may be 

thought of as consisting of a zero-time stage, an immature stage, and a mature stage. To these perhaps 

could be added a fourth or senile stage.

Zero-time stage is the parent-material stage. There 

is no differentiation of the soil horizons, no soil structure, and no appreciable clay mineral development. 

This stage is easily recognized in materials like recent 

volcanic ash or recently exposed rock. However, if 

the parent material happens to be one of the layers of 

paleosol, recognition of the zero-time stage, or even of 

some of the later stages, is by no means an easy matter.

Tamm (1920) and a number of other investigators, 

including Mohr, are of the opinion that this initial stage 

of soil formation is relatively brief. Whenever soils

have been dated with the aid, for example, of archeological evidence (Akimtzev, 1945) or historic events 

(Van Baren, 1931; Zemiatchenskii, 1906; Ognev, 1927), 

the initial stage has been characterized by zonal trends 

in the chemical composition of the humus and in some 

cases by appearance of clay minerals but not by a morphologically recognizable differentiation of the soil 

horizons. The duration of this initial stage apparently 

is to be measured in decades or at most a few centuries.

The subsequent immature, mature, and senile stages 

of pedologic age apparently require a progressively 

longer time to develop fully the clay minerals or stable 

oxides and to develop the distinctive horizons of the soil 

profile.

Depending on the environment, the characteristics 

of a given pedologic age may differ from one region to 

another. Also dependent on the environment is the 

rate at which a soil develops to a given pedologic age. 

Environments not only are very different in different 

parts of the world, they have been very different at 

different times in the geologic past. It is difficult 

enough to judge the absolute or chronologic age of most 

soils; it is equally difficult, if not more so, to judge their 

pedologic age.

0 -

5ft10ft15ft20ft1 Wisconsin or younger soil profile superimposed on top of paleosol. 

Top few inches (a) are humus rich and dark gray or brown. This 

layer and a thinner lighter-colored layer (b) immediately below it 

are lime-free. If limy colluvial material has accumulated on 

surface, several inches (c) of lime-enriched paleosol occur at the 

base of this soil.

Pre-Wisconsin soil, the paleosol. Top several feet (d) consist of 

lime-free reddish-brown clay, in places probably clay loam. Structureless or prismatic structure. Any contained stones are inert 

materials like quartzite. Sand grains commonly pitted. Lower 

part of this clayey layer may contain tiny veinlets of CaCOo. 

Under the lime-free clayey layer are -many feet (e) of lime-enriched 

weathered parent material. In the upper part of this layer stones 

are commonly residual jand can be cut with a knife. Increasing 

proportion of firm unweathered rock downward. Matrix, especially 

in upper part, may be clay like in (d), but this clay is generally 

impregnated with lime and is powdery. Lime may occur in closely 

spaced, anastomosing veins, in irregular blebs an inch or so in 

diameter, or finely and evenly disseminated throughout the layer.

At the base (f) of the paleosolis comparativelyfresh and unweathered 

parent material. CaCO^ commonly extends into joints in the upper 

part of this layer.

10. Diagrammatic profile of pre-Wisconsin soil, or paleosol, in the Rocky Mountain region.
PRE-WISCONSIN SOIL IN THE ROCKY MOUNTAIN REIGION 111

PALEOSOL IN THE ROCKY MOUNTAIN REGION

The paleosol discussed in this paper is pre-Lake 

Bonneville in age. It is older than the latest of the 

moraines in the Wasatch Range but is younger than 

the earlier ones. It is older than the oldest alluvial 

deposits along the South Platte River in the Denver 

Basin.

In its most complete development, at least as thus far 

observed, the paleosol is distinctive and readily recognized where complete profiles are preserved. It consists of several feet of lime-free reddish or brownish 

clay that grades downward into many feet of progressively less weathered and more strongly lime enriched 

parent material. The soil seems to be largely if not 

entirely the product of weathering of the parent material in place. The consistent great thickness, at least 

30 feet in the Lake Bonneville Basin and at least 15 

feet in the Denver Basin, distinguishes the paleosol 

from modern soils having a similar profile.

Figure 10 is a diagrammatic profile of the paleosol.

GEOGRAPHIC EXTENT?

The paleosol has been recognized in a good many localities in Utah and Colorado and at one locality in New 

Mexico (fig. 11). It is probably widespread in the 

Rocky Mountain region and Great Basin. The areal 

extent of the paleosol at the localities shown in figure 

11 ranges from a few acres to a few square miles.

In the vicinity of Utah Lake and Denver the paleosol 

has been identified, and systematic geologic mapping 

has shown the stratigraphic relations and made it possible to date it. At other localities shown in figure 11 

the paleosol has been identified on the basis of lithologic 

and physiographic evidence.

Some of the localities where the paleosol has been 

identified are on steep slopes in the mountains, and 

others are on rather smooth or gently rolling upland 

surfaces. They range in altitude from 5,000 to more 

than 8,500 feet and occur in several different soil and 

floral zones. The range in the modern environment 

ef the localities already recognized is considerable and 

probably as the study progresses will be extended.

As a matter of fact, the paleosol in the Rocky Mountain region is probably closely related to the gumbotils 

in the Middle West and to the pre-Wisconsin soils in 

the eastern States.

PARENT MATERIALS

As brought out in figure 11, the paleosol has been developed on a considerable variety of parent materials. 

These materials include Paleozoic and Mesozoic sedimentary rocks of all kinds, Tertiary lavas, and Pleistocene f anglomerate or moraines containing various proportions of different kinds of sedimentary, igneous, and 

metamorphic rocks. Despite this variety of parent materials, the paleosol looks much alike at all the localities; 

it is a lime-free clay layer overlying a thicker layer of 

weathered and lime-enriched parent material.

The variety of parent materials on which the paleosol 

in the Rocky Mountain region has developed offers an 

interesting comparison with the gumbotils in the Middle 

West, which have developed on sheets of glacial drift 

that are different in age but rather similar in composition. Similar glacial deposits in the Rocky Mountain 

region probably developed paleosols like the gumbotils.

CLAY LAYER

The upper clayey part of the paleosol commonly is 

eroded, and consequently its thickness varies greatly. 

The maximum thickness found thus far is 10 feet; in 

general, however, it is only a few feet thick, and in some 

places the clay layer is entirely removed.

The clay is massive and not stratified. Field tests 

utilizing the Cenco-Wilde hydrometer method indicate 

that the silt-clay content of the clayey layer is rarely 

less than 50 percent and locally is as high as 75 percent. 

The clay content is high even where the parent rocks 

are nonargillaceous.

The lower part of the clayey layer locally contains 

relic pebbles or cobbles that can be cut by a knife. This 

condition is especially characteristic of the soil where 

the parent material includes a rather large amount of 

dioritic or more basic igneous rocks. Firm pebbles in 

the clay are almost exclusively of the inert siliceous 

types.

A considerable percentage of the sand grains in the 

clay layer are subangular and deeply pitted. They 

could not have been transported very far and probably 

developed their form within the clay deposit of which 

they are a part.

The massive clay generally breaks with a prismatic 

structure. Its general physical appearance and feel are 

the same, regardless of the parent material or obvious 

variations in the environment of the locality in which 

the remnant of the paleosol is preserved.

The essential constituents, other than the alkalies, of 

three samples studied are given in the table, page 113. 

The high content of iron oxide made index measurements of the clay minerals impossible. A thermal 

analysis by George T. Faust and an X-ray powder examination by Joseph M. Axelrod, both of the United 

States Geological Survey, indicate that the clay is predominantly hydromica. A minor quantity of montmorillonite is present.
112 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1949

NEW «/M E X I

16 \ / Albuquerque

FIGURE 11. Localities in Utah, Colorado, and New Mexico where pre-Wisconsin soil has been identified.

1. Wasatch Range between Brigham City and Logan, Utah. Parent material, Paleozoic limestone.

2. Traverse Range, Utah. Pennsylvanian limestone and quartzite; Tertiary or early Pleistocene fanglomerate composed of diorite, limestone, and 

quartzite debris.

3. Alpine Canyon, Utah. Glacial moraine composed chiefly of dioritic rock debris.

4. Wasatch Range, northeast of Pleasant Grove, Utah. Mississippian shale; Pennsylvanian limestone and quartzite; Tertiary or early Pleistocene fanglomertate composed of limestone, shale, and quartzite.

5. Wasatch Range, Provo Canyon, Utah. Same parent material as that at locality 4.

6. South side of Utah Lake Valley, Utah. Tertiary or early Pleistocene fanglomerate composed of limestone, shale, and sandstone.

7. West side of Utah Lake Valley, Utah. Same parent material as that at locality 6.

8. Tintic mining district, Utah. Tertiary latite.

9. Between Price and Woodside, Utah. Tertiary or early Pleistocene fanglomerate composed of sandstone, limestone, and shale derived from Cretaceaus formations.

10. Iron Springs district, Utah. Mesozoic formations (?).

11. Henry Mountains, Utah. Tertiary or early Pleistocene colluvial deposits and fanglomerate containing diorite, shale, and limy sandstone 

fragments.

12. Green River Desert, Utah. Earthy Mesozoic sandstone.

13. La Sal Mountains, Utah. Same parent material as that at locality 11.

14. Front Range, Idlewald, Colo. Fanglomerate composed of gneiss and schist fragments.

15. Denver Basin, Colo. Shale, earthy sandstone, and conglomerate of Denver formation; gravels and other surflcial deposits overlying Denvej 

formation.

16. Mount Taylor, N. Mex. Basaltic lava.

17. Mesa Verde National Park, Colo. Cretaceous shale and limy sandstone.

Examined under the petrographic microscope, sample 

1 was found to contain approximately 20 percent of 

quartz and 20 percent of orthoclase, sample 2 about 25 

percent of quartz and 20 percent of orthoclase, and 

sample 3 about 20 percent of quartz and 15 percent of 

orthoclase.

A number of other samples were studied by M. E. 

King in the Petrographic Laboratory, Research and 

Geology Division, United States Bureau of Reclamation at Denver. For identifying the clay minerals Mr. 

King used staining tests and confirmed them by X-ray 

diffraction and differential thermal analyses. He analyzed 18 samples of paleosols from 10 localities. 

Hydromica was found to be the principal clay mineral 

in the paleosol at six of the localities where the parent 

materials are limestone, shale, diorite, or unconsolidated deposits composed of these materials. Montmorillonite was found dominant in the paleosol at four
PRE-WISCONSIN SOIL IN THE ROCKY MOUNTAIN REIGION 113

Partial chemical analyses, in percent, of samples of clays from some ancient soils in Utah

[J. J. Fahey, analyst]

1. Old soil on oldest of glacial moraines by Dry 

Creek, above Alpine. _________

2. Old soil on fanglomerate from near reservoir in 

Traverse Range about 2 miles northwest of 

Alpine

3. Old soil formed on Manning Canyon shale, south 

side of Provo Canyon, by Pole Canyon road

Loss on 

ignition

6.78

6. 88

6.83

SiO2

67.37

69. 61

66.07

A12 O3

13. 86

12. 65

15.54

Fe2 O3

5. 10

4. 58

6.02

MgO

1.67

1.51

1.87

CaO

0.02

.02

.02

TiO2

0.75

.70

.96

MnO

0.003

.003

.003

localities, at two of which the parent material is glassy 

volcanic rock and at two in part loessial. In all cases 

tested the clay mineral found dominant in the clay layer 

was also found dominant in the underlying lime-enriched layer.

Mr. King also analyzed four other samples of alluvium, three of which were from clayey alluvial deposits 

believed to have been derived by erosion of the paleosol. 

Montmorillonite is the dominant clay mineral in all 

these samples of alluvium.

The clay more than a foot below the present surface 

commonly is reddish brown; less commonly it is red 

or dark reddish-gray. In terms of the standard color 

chart in use by the Division of Soil Survey, United 

States Department of Agriculture, the colors are of the 

hues 2.5 YE, and 5 YR; the range in chroma is 2 to 

6 and the range in value is 3 to 5, according to the 

Munsell system. Mineralogic and chemical studies also 

are needed to determine to what extent the color differences reflect variations in original composition or variations in the degree of oxidation of the materials at the 

locality. The range in color, however, is remarkably 

slight, considering the great range in kind and color 

of the parent materials and the rather large range in 

the kinds of environment in which the paleosol has been 

found.

The clay has lost lime carbonate and probably other 

salts by leaching. More than a foot below the surface 

its*pH as determined colorimetrically ranges from 6.5 

to 7.5 and increases downward. The degree of leaching 

in the old soil is impressive because even at localities 

where the parent material is mostly limestone, as at 

many places along the Wasatch Range, the clay is 

known to be lime-free to depths of as much as 10 feet.

A still unanswered question is the degree to which 

the clay layer represents weathered loessial materials. 

The similarity of the clay over so large an area and 

over so many different parent materials might suggest 

that at least part of the clay is weathered loess. However, we suspect that most of the clay is the residual 

product of weathering of the rocks on which it has 

formed, for the following reasons: Soft decomposed

889404 50 2

fragments of the rock may be found in the lower part 

of the clay; the clay layer is gradational downward into 

the lime-enriched layer of weathered parent tock; and 

the amount of lime in the lime-enriched layer under the 

leached clay appears to ^ be proportional, at least 

roughly, to the amount of lime in the parent rock. If, 

for example, the clay layer of the paleosol in the 

Wasatch Range, which is a highly calcareous region, 

were derived largely from loess there should be a distinct lime-enriched layer even where the bedrock is 

granitic.

The clay layer of the paleosol in the Rocky Mountain 

region is like the upper part of the gumbotils in the 

Middle West, where the proportion of siliceous types 

of pebbles increases upward through the old profile. 

Kay and Pearce (1920, pp. 101-105), for example, 

found that 80 to 90 percent of the pebbles in the upper 

layer are siliceous, and this proportion decreases downward to about 20 percent in the underlying till.

Much additional work needs to be done investigating 

problems of paragenesis of clay minerals under various 

pedologic environments. There is some evidence that 

weathering of rocks into soil, under given environments, 

tends to result in the formation of distinctive types of 

clay minerals (Sedletzkii, 1941 and 1945). Unfortunately, developing the evidence to the point where use 

can be made of the findings is hampered by the fact that 

paleosols almost certainly are the product of a complex 

of environments.

In the Lake Bonneville and Denver Basins our preliminary data seem to indicate that the clay in the 

unquestionably Wisconsin or younger soils is largely 

montmorillonitic, whereas the clay in the paleosol appears to be largely illitic. Unfortunately, the Wisconsin and younger soils that have been tested are largely 

on fluvial, lacustrine, or eolian deposits rather than on 

bedrock, and perhaps the clay mineralogy is related to 

the processes of sedimentation rather than to processes 

of weathering. It would be significant, however, if the 

paleosol really is composed rather consistently of illitic 

clay regardless of differences in the kind of parent material from which it was formed.
114 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1949

Ginzburg (1946) has suggested that illite may 

weather to montmorillonite if the environment is 

changed so as to increase the salinity but that illite may 

weather to kaolinite if the environment is changed 

so as to increase the acidity. If there is merit in this 

suggestion it may be possible to correlate the clay mineralogy with the changes in Wisconsin and Recent 

climates.

Also needing investigation, and possibly related to 

problems of paragenesis of the clay minerals, is the matter of distribution of trace elements in the paleosol. 

Trace elements associated with various clay minerals 

may occur in a number of ways, for example, as discrete 

mineral fragments; in solid solutions replacing such 

elements as aluminum, silicon, iron, magnesium, potassium, and calcium; in the double layer surrounding the 

clay micelle; in the interplanar spaces of the clays; and 

in association with the organic-mineral colloidal complexes. Despite these variations in mode of occurrence 

certain pedogenic processes seem to result in stable 

vertical distribution trends of trace elements in soil profiles (Malinga, 1946, and Siniagin, 1946), and these 

distribution trends may be distinctive of certain environments. Where the paleosol is no longer within the 

zone of pedogenesis and where differences between the 

ancient and the modern environments are considerable, 

marked differences between the ancient and the modern 

trends in the trace element distributions may be 

expected.

Too few tests have been made to determine whether 

or not the distribution trends of trace elements are 

orderly in the paleosol in the Rocky Mountain region. 

The few random tests made thus far indicate only that 

the clay layer seems to have a somewhat higher content 

of lead and zinc than does the underlying lime-enriched 

layer.

LIME-ENRICHED LAYER

Beneath the clay is a layer of weathered parent material strongly enriched with lime carbonate. The thickness of this lime-enriched layer and the amount of 

carbonate it contains varies widely, depending on the 

composition and permeability of the parent material.

Where the paleosol has developed on very calcareous 

parent material, the lime-enriched layer may be 

strongly developed through a thickness of 20 feet or 

more. Such thicknesses are found in the Wasatch 

Range where the paleosol developed on Paleozoic limestones and on fanglomerate containing a considerable 

amount of limestone. On the other hand, where the 

parent material is not calcareous, or only moderately 

so, but contains sufficient calcium to develop calcium 

carbonate on weathering, the lime-enriched layer is 

only a few feet thick or only weakly developed through 

a greater thickness. For example, where the paleosol 

has developed on lavas or on some sedimentary rocks

that are only moderately calcareous, like the Denver 

formation, the lime-enriched layer is 5 to 10 feet thick.

A complicating factor in evaluating variations in 

thickness of the lime-enriched layer is the variation in 

permeability reflecting stratification of the parent material. For example, glacial moraine in Alpine 

Canyon, Utah (locality 3, fig. 11), contains only a 

small amount of limestone, and there is little calcium 

in the granitic or dioritic rocks that comprise the bulk 

of the moraine. The lime-enriched layer in the paleosol on this moraine is feebly developed; it contains only 

a trace of secondary lime carbonate. This moraine, 

however, is permeable, and the carbonate is distributed 

through a zone at least 20 feet thick, whereas on other 

parent materials that are distinctly stratified, like the 

Denver formation, the lime-enriched layer is only a 

few feet thick but strongly developed.

The calcium carbonate in the lime-enriched zone occurs in several ways. Commonly it forms irregular 

lime-rich layers separated by less-rich layers. It occurs also in scattered irregular masses an inch or two 

in diameter, as a fretwork of tiny anastomosing veinlets, or it may be finely and rather uniformly distributed throughout the enriched layer. Where the 

parent material is gravelly the pebbles are generally 

crusted with lime. The pH of the lime zone ranges 

from 7.5 to slightly more than 8.0. The alkalinity increases downward.

In the Middle West small quantities of secondary 

calcium carbonate are reported below the gumbotils 

(Kay and Pearce, 1920, pp. 120-124, and Leighton and 

MacClintock, 1930, pp. 36-38), but the amount of 

secondary lime seems to be much less than in the Rocky 

Mountain region. To what extent this difference in 

lime content of the subsoil in the two regions reflects 

differences in composition and permeability of the 

parent materials or differences in the climatic regimen 

that existed when the paleosols were developed is a 

problem that needs more investigation; it touches on 

some rather fundamental concepts of soil genesis.

AGE OF THE PALEOSOL

STRATIGRAPHIC EVIDENCE IN THE LAKE 

BONNEVILLE BASIN

At the mouth of Alpine Canyon, Utah (locality 3, 

fig. 11), the paleosol, which includes a thick leached clay 

layer and a thick but weakly lime enriched layer, is 

developed on the older but not on the younger of the 

moraines in that canyon (Hunt, in preparation). The 

younger moraine was contemporaneous with one of the 

high-level stages of Lake Bonneville, and at many places 

in Utah Valley the paleosol is overlapped by the lake 

beds (fig. 12). Moreover, the oldest formation of the 

Lake Bonneville group, the Alpine formation, contains a 

much higher proportion of clay and silt than do the
PRE-WISCONSIN SOIL IN THE ROCKY MOUNTAIN REGION 115

Post-Lake Bonneville soilPost-Lake Bonneville 

alluvial gravel

Lake Bonneville group

FIGUBB 12. Diagrammatic cross section illustrating some relationships between the geology and soil development in the 

Lake Bonneville Basin, Utah. Paleosol in the pre-Lake Bonnerville deposits is discordant with the present topography 

and is overlapped by the Lake Bonneville group and post-Lake Bonneville alluvial gravel. A post-Lake Bonneville soil 

is feebly developed on the Lake Bonneville and younger deposits and is superimposed on the old soil.

younger ones and probably represents the sediment that 

was formed by the erosion of the paleosol from adjoining highlands (Hunt, in preparation). There does not 

seem to be any other reasonable source for so much clay 

in the Alpine.

In the Lake Bonneville Basin, therefore, the paleosol 

must have developed during one of the Pleistocene interstadial periods that preceded Lake Bonneville.

STBATIGRAPHIC EVIDENCE IN THE DENVER BASIN

In the Denver Basin there is some paleontologic as 

well as general stratigraphic evidence that the paleosol 

is of pre-Wisconsin Pleistocene age.

Deposits along the South Platte River Valley identified as Wisconsin in age include a thick fill of cobblesize gravel evidently representing outwash from the 

early Wisconsin glaciers. Derived from this fill and 

extending eastward from it is an extensive loess. Along

W.

the valley this loess is overlain by a younger pebblesize gravel fill that evidently represents outwash from 

the late Wisconsin glaciers. Bones collected from the 

loess and younger gravel have been identified by C. L. 

Gazin of the United States National Museum and Jean 

Hough of the United States Geological Survey, who 

report that the collections include camel, bison, antelope, and extinct rodents and confirm a Pleistocene age 

for the deposits. The collections were not good enough 

to permit identification of species. Artifacts of bone 

and flint, identical with those associated with the Folsom culture at the Lindenmeier site, have been collected 

from the late Wisconsin gravel by Alice P. Hunt.

The paleosol is overlain by and must be older than 

the loess (fig. 13), but it has not yet been found under 

the early Wisconsin gravel. However, those gravels nowhere are weathered to clay; they are fresh firm stone 

and leave little doubt but that they are younger than the 

paleosol.

E. 

PaleosoK

, Clay loyer

Loess

Lime-enriched layer

Late Wisconsin gravel fill

Early Wisconsin gravel fill

13. Diagrammatic cross section illustrating topographic and stratigraphic relations of the paleosol in the Denver 

Basin. Paleosol has developed on the Denver formation and on old surflcial deposits (not shown) that lie on the Denver. 

The paleosol is older than the loess and must be older than the early Wisconsin gravel fill, which was the source of the 

loess.
116 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1949

The paleosol has developed on some older gravels, 

and horse bones suggestive of Yarmouth age were collected from one of these. Some of these old weathered 

gravels are on the uplands and others are within the 

valleys, and these assuredly are Pleistocene also.

Along the tributaries of the South Platte Kiver the 

oldest alluvium is distinctive in being composed very 

largely of clay. The younger alluvial deposits contain 

more silt, sand, and gravel. Correlation of the clay 

alluvium with the Wisconsin gravel fill in the South 

Platte River Valley is not established, but the general 

relations suggest that the clay alluvium is at least as 

old and perhaps somewhat older than the gravel fill. 

The clay alluvium in the Denver Basin, like the Alpine 

formation in the Bonneville Basin, apparently is the 

product of erosion of the paleosol.

The evidence in the Denver Basin, although not conclusive, leaves little doubt that the paleosol is preWisconsin in age.

TOPOGRAPHIC EVIDENCE

In all the areas examined thus far the paleosol is associated with a distinct topographic unconformity. 

Throughout the Rocky Mountain region are found remnants of an old topographic surface or surfaces distinct 

from the more rugged and rocky topography that is 

being carved today. The old topography seems to have 

had as great relief as there is today, but the land forms 

had smoother contours. They were the product of a 

time when the processes of weathering and soil development exceeded those of erosion quite the reverse of the 

Wisconsin and younger climatic environments in which 

the rate of erosion was and is greater than the rate of 

weathering.

As would be expected, the remnants of the old topography are preserved only in areas that have been protected against late Pleistocene and Recent erosion. 

These areas are mostly along the divides. In the mountains they are far back from the main drainage lines 

that discharged glacial meltwaters, but they may lie 

close to other drainage courses that have small 

catchment areas and have not been actively cutting during late Pleistocene and Recent time.

In the Wasatch Range, Utah, remnants of the old 

topography are preserved at all altitudes from the 

very base of the range to some of its highest divides. 

In parts of the Colorado Plateau, remnants of an old 

topography are preserved on some of the broad upland 

surfaces and even locally along the sides of some of the 

canyons. In the Denver Basin the old topographic surface had more relief than there is today, because the 

valleys that are there now are alluviated and the interstream divides are lower (fig. 13).

The paleosol is invariably associated with the old

topographic surface; in fact the old topography provides an excellent clue for finding paleosol remnants.

The intimate and apparently invariable association 

of the paleosol with old topographic surfaces provides 

confirmatory evidence of the antiquity of the deposit. 

The old surfaces of course could be, and in many places 

no doubt are, much more ancient than the soil now on 

them. However, the paleosol in the Rocky Mountain 

region, like the gumbotils in the Middle West (Kay and 

Pearce, 1920, p. 89), does not occur on Wisconsin or 

younger deposits or on surfaces that are known to have 

been eroded during or since Wisconsin time.

In areas like the Great Basin, where Quaternary 

structural movements have been considerable, there 

has been a tendency to attribute topographic unconformities to the structural changes. The evidence at 

hand, however, suggests that changes in climate during the Pleistocene were fully as important as structural movements, if not more so, in developing those 

topographic unconformities, because the unconformities extend into provinces like the Colorado Plateau 

and into the High Plains where local differential structural movements have been slight, at least during the 

Pleistocene. It is quite possible that even during the 

Pleistocene our western mountains went through a 

succession of changes that at some stages gave rise to 

topographic forms like those we see today and at other 

stages gave rise to forms as rounded as those in the 

Appalachians. The relative importance of climatic 

changes as against structural movements in developing 

land forms needs to be reevaluated.

DIFFERENCES BETWEEN THE PALEOSOL AND THE 

WISCONSIN OR YOUNGER SOILS

On the Lake Bonneville and on other assuredly Wisconsin or Recent deposits the development of modern 

soils involves leaching of lime and other salts from 

the top layers and deposition of these materials under 

the leached layer. Except very locally where there 

is an excess of water this leaching during late Wisconsin and Recent time has not exceeded a couple of feet, 

at least in the region being considered, and nowhere 

on known Wisconsin or Recent deposits in this region 

have hard rocks been decomposed into residual clay 

in more than very small quantities. Except at scattered and isolated localities, where conditions of water 

supply are unusual, the soils developed on Wisconsin 

and Recent deposits in the Rocky Mountain region are 

characterized by the domination of the parent material in the profile, not only in the lower lime-enriched 

layer but also in the leached upper layer. This generalization apparently holds true also in the middle western States (Kay and Pearce, 1920, p. 89) and may apply 

in the eastern States as well.
PRE-WISCONSIN SOIL IN THE- ROCKY MOUNTAIN REGION 117

The modern soils in the Rocky Mountain region are 

quite unlike the paleosol in that they are shallow and 

lack the strong development of clay that can be attributed to rock decomposition. Clayey parent materials, of course, like some loesses or alluvium, have given 

rise to clayey modern soils, but these rarely will be 

confused with paleosol. The characteristics of the 

paleosol are similar over a large.region reaching into 

several western States, and the differences between it 

and the modern soils are equally widespread.

SOME PROBLEMS IN IDENTIFYING REMNANTS OF THE 

PALEOSOL

It is evident from the age of the paleosol and from its 

topographic position that it has been subjected to a great 

deal of erosion. At few places is the full thickness 

preserved, and outcrops at these places seldom expose all 

of it. One rarely sees in outcrops or excavations more 

than about a fourth of the total profile of the paleosol, 

and usually only the lime-enriched layers have survived erosion. All too commonly the leached clay, the 

most diagnostic layer, has been removed.

No very satisfactory criteria have been developed as 

yet for distinguishing erosion remnants of the limeenriched lower layers of the paleosol from other kinds 

of caliche. The difficulty is not lessened by the fact that 

all the near-surface lime-enriched deposits, regardless 

of their age or origin, have been altered to some extent 

by modern soil processes.

Where as much as 2 feet of clay is preserved on top 

of the limy layers it is usually possible to determine 

where the material is the product of transportation or 

of weathering in place. Thinner clay remnants generally are not satisfactory because they are apt to have 

been disturbed by physical changes, such as frost heaving, or by plant, animal, or human activity. Such disturbance obscures stratification in transported materials 

and may contaminate residual materials with fragments 

of foreign rock, mineral grains, or salts.

Some lime-enriched deposits are too thick to have 

derived their lime from an overlying thin leached 

layer; in such cases the regional geology is sometimes 

helpful in determining whether the lime was developed 

by weathering in place or by other processes. If the 

drainage basin in which the lime-rich zone occurs lies 

wholly within formations.that are only slightly or not 

at all calcareous the lime generally can be attributed to 

rock decomposition. Moreover, the lime layer can be 

attributed to concentration by soil processes rather than 

to lateral transportation by ground water where, as in 

parts of the Denver Basin, the lime-rich layers rise up 

the sides and across the tops of isolated hills composed 

of horizontal strata having different permeabilities. 

At such localities it is reasonable to infer that the clay 

layer originally was present in considerable thickness

and covered the entire hill, that the clay has largely 

been removed by erosion, and that remnants of it are 

likely to be found in nearby protected places.

The regional geologic environment of some caliche deposits can be equally or even more diagnostic of an 

origin distinctly not related to paleosol, as, for example, the lime carbonate deposited by Lake Bonneville 

at headlands or other places that were exposed to 

strong surf action (Gilbert, 1890, p. 168, and Hunt, in 

preparation).

In the lime zone of the paleosol, clay commonly is developed in the upper few inches, and locally in the upper 

few feet. The occurrence of such clay in caliche deposits suggests that the deposit might represent the 

lower layer of a paleosol whose original clay surface 

layer has been largely removed. Also, in the lime zone 

of the paleosol the alkalinity increases downward, and 

the degree of weathering of the parent material increases 

upward. These conditions would be expected of 

processes that operated vertically, and their occurrence 

in caliche deposits also suggests that the deposit might 

represent the lower layer of a paleosol.

Such observations, however, are at best only suggestive, and before the paleosol can be used very extensively 

as a means for stratigraphic correlation additional ways 

must be found for distinguishing erosion remnants of 

its lime-enriched subsoil from other kinds of caliche. 

The paragenetic association of certain clay minerals 

with certain zonal soils, suggested by the work of Sedletzkii (1945), if confirmed by further work, may be 

valuable in identifying remnants of paleosol.

Much more remains to be learned about the old soil 

itself, including the mineralogy of its clays, the vertical 

zoning of the soluble forms of the metals and other elements, and its possible content of pollen and spores. 

Until these data are assembled and the facts sifted, the 

surest method for identifying a remnant of paleosol is 

to map the deposit carefully and determine its relation to 

the land surface, to the parent material, and to adjoining Pleistocene deposits. We still cannot establish the 

identity of paleosol from the evidence contained in a 

single exposure; at this stage determination still depends upon the areal relationships.

ORIGIN OF THE PALEOSOL AND ITS BEARING ON 

PLEISTOCENE HISTORY

The paleosol records a period when the processes of 

weathering greatly dominated over those of erosion. 

The climate that produced it must have been quite unlike 

the present climate or any of the succession of climates 

that have prevailed during and since Wisconsin time in 

the Rocky Mountain region.

Deep soils representing the residual effect of rock 

weathering commonly are attributed to considerable absolute age, but the age is probably one of the least im-
118 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1949

portant of all the factors that must have controlled the 

development of so deep and mature a profile as characterizes this soil (Hunt, 1948). Its depth is several times 

greater than the depth to which soil processes have operated during and since Wisconsin time. During the 

last 50,000 years or so the profile of the old soil has not 

been changed, except in its uppermost layers. Where 

it has been buried and protected by younger deposits it 

is the same as where it is still at the surface.

It is even possible that the paleosol actually required 

no longer time to develop than has been required by 

the shallow Wisconsin and younger soils in this region. 

Given favorable moisture and temperature conditions 

and appropriate animal and vegetable life to accelerate 

biochemical activity, it is not at all difficult to visualize 

rather rapid rock decomposition and deep soil development. That something of this sort did occur is suggested by the seeming nonexistence, at least in this 

region, of soils that are gradational in depth and 

maturity between the late Pleistocene or Recent soils 

and those that can be dated stratigraphically as preWisconsin. The differences between the paleosol and 

the modern soil assuredly are due not to difference in 

the length of time required for them to develop but 

to major differences in the climates under which they 

were developed. Until we know more than we now 

know about the environment or environments under 

which the paleosol developed, we are in no position to 

evaluate time as a factor in its development.

The topographic unconformity with which the paleosol is associated is further evidence that climate rather 

than time is critical in controlling the development of 

the paleosol. Climate determines whether erosion or 

weathering will be dominant in a given topography; 

time is important only to the degree that it allows 

changes in climate.

In regard to rock weathering, the Wisconsin and 

post-Wisconsin climates have been virtually impotent, 

yet they have been operating for something like 50,000 

years on the early Wisconsin deposits and for 10,000 or 

so years on some of the younger deposits. If the great 

difference between the paleosol and the younger soils 

were due largely to the time factor many millions of 

years would certainly have been required to develop the 

paleosol on the hard rock formations on which it is so 

commonly found. The geologic record obviously is 

against this.

Soil scientists will have to decide to what extent the 

old soil represents a complex of profiles superimposed 

on one another and the probable kind of climate or 

succession of climates that produced the profile that 

is found in the paleosol. The great depth of the clay 

and the softly contoured land forms on which the 

paleosol is present implies considerable moisture, but 

the development of the lime-enriched layer is difficult

to explain if there was such abundant moisture. Would 

40 inches of rain, distributed, let us say, in two rainy 

seasons spring and fall develop the kind and thickness of layers that are found in the paleosol? Whatever the conditions were that produced the soil, they 

appear to have been general over a wide area in the 

Rocky Mountain region.

In most of the western mountains where glacial deposits are found the older deposits generally are described as more weathered than the younger (Atwood, 

1909; Blackwelder, 1915; Atwood and Mather, 1932, 

pp. 101-111; and Bryan and Ray, 1940). The differences, however, in the kind of weathering products 

in the old and in the young deposits need further study. 

Certainly in the Wasatch Range, and probably in 

several of the other ranges, the older glacial deposits 

are blanketed by the paleosol that has been the subject 

of this paper. A comparative study of pre-Wisconsin 

soils in the West and a comparison of these soils with 

the pre-Wisconsin soils, including the gumbotils, in the 

Middle West and with the presumed old soils of the 

southern Appalachians and northern Pennsylvania 

would be invaluable. It would contribute to better 

understanding of the origin of the old soils; it would 

improve our knowledge about the climatic and other 

variable factors that influenced their development; and 

it might lead to establishing the means for using soils 

for stratigraphic correlation,

PARTIAL BIBLIOGRAPHY

Soils attributable to past climates have been widely 

recognized, particularly by geologists who have endeavored to use them for stratigraphic correlation and 

for interpreting Pleistocene and Recent history. Apparently, though, geologists have not studied paleosols 

intensively for a better understanding of soil genesis. 

Until better understanding of paleosols is achieved, 

their use in solving geologic and other problems is 

bound to be limited.

Our review of literature dealing with old soils and 

related problems is no more complete than is the rest 

of our investigation, which, it is hoped, will be continued. The following incomplete bibliography lists 

the references that have been found so far citing occurrences of paleosols or dealing with problems connected 

with them.

AKIMTZEV, V. V., 1945, o vozraste pochv prikaspiiskoi nizmennosti

Kavkaza [in Russian]: Pochvovedenie, no. 9/10, pp.

481-488.

Cites pedologic evidence of the Caspian transgression,

which took place about 40 centuries ago. The evidence is

supported by archaeologic findings. 

ANTIPOV-KARATAEV, I. N., and PBASOLOV, L. I., 1932, Pochvy

Krymskogo Gosvdarstvennogo Zapovednika: Akad. Nauk,

Pochv. Inst., Trudy, vol. 7, pp. 5-280. 

Cites recognition of a paleosol.
PRE-WISCONSIN SOIL LN THE' ROCKY MOUNTAIN REIGION 119

ABMASHEVSKII, P. IA., 1883, in Kiev. Obsch. Estestvoispytateli, 

Zapiski, vol. 7, no. 1.

Original not available. Cited by G. M. Ponomarev. 

Evidently describes three or four buried paleosol profiles. 

ATWOOD, W. W., 1909, Glaciation of the Uinta and Wasatch 

Mountains: U. S. Geol. Survey Prof. Paper 61.

Gives several references to deep weathering of the older 

glacial deposits.

 1916, The physiographic conditions at Butte, Mont., and 

Bingham Canyon, Utah, when the copper ores in these districts were enriched: Econ. Geology, vol. 11, pp. 697-740.

ATWOOD, W. W., and MATHER, K. F., 1932, Physiography and 

Quaternary geology of the San Juan Mountains, Colorado: 

U. S. Geol. Survey Prof. Paper 166.

BLACKWELDER, ELIOT, 1915, Post-Cretaceous history of the mountains of central western Wyoming: Jour. Geology, vol. 23, 

pp. 321-333.

BOBDAS, JEAN, and MATHIEU-REVEBDY, GASTON, 1943, Essai de 

Pgdologie M6diterran4enne, Les sols de la region du BasRh6ne, 104 pp., Paris, Imprimerie Nationale.

States that parent material of some of the soils probably 

is paleosol. Includes a bioliography of 322 references.

BRYAN, K., 1927, The "Palouse soil" problem: U. S. Geol. Survey 

Bull. 790-B.

States that old soils are involved in the complex problem 

of the Palouse soil, but mineralogic studies indicate that the 

clayey lower part is a weathered loess or volcanic ash and 

not residual weathered bedrock.

 1940, Soils and periglacial phenomena in the Carolinas:

Science, new ser., vol. 91, pp. 523-524. 

BKYAN, K., and ALBRITTON, C. C., JR., 1943, Soil phenomena as

evidence of climatic changes: Am. Jour. Sci., vol. 241, pp.

469-490. 

A study of a complex soil profile in Texas leading to

interpretation of climatic changes and correlation with

geologic events. 

BKYAN, KIRK, and RAY, L. L., 1940, Geologic antiquity of the

Ldndenmeier site in Colorado: Smithsonian Misc. Coll., vol.

99, no. 2, p. 28. 

CHANDLER, R. F., JR., 1942, The time required for podzol profile

formation as evidenced by the Mendenhall glacial deposits

near Juneau, Alaska: Soil Sci. Soc. America Proc., vol. 7,

pp. 454-459.

States that a podzolic profile about a foot deep has developed on moraines approximately 1,000 years old. 

COLEMAN, A. P., 1941, The last million years, a history of the

Pleistocene in North America, 216 pp., Toronto, Canada,

Univ. Toronto Press. 

CONDRA, G. E., REED, E. C., and GORDON, E. D., 1947, Correlation

of the Pleistocene deposits of Nebraska: Nebraska Geol.

Survey Bull. 15, 73 pp. 

A summary of Pleistocene stratigraphy, including old

soils. 

CROCKER, R. L., 1946, Post-Miocene climatic and geologic history

and its significance in relation to the genesis of the major

soil types of South Australia: Australia, Council Sci. Ind.

Research Bull. 193, 56 pp. 

FLINT, R. I1., 1947, Glacial geology and the Pleistocene epoch,

589 pp., New York, John Wiley and Sons.

 1949, Leaching of carbonates in glacial drift and loess 

as a basis for age correlation: Jour. Geology, vol. 57, pp. 

297-303.

States that mean depth of leaching is not regarded as a 

reliable criterion for correlating deposits of less than stage 

value stratigraphically.

FREEMAN, O. W., 1926, Mammoth found in loess of Washington:

Science, new ser., vol. 64, p. 477.

Elephant bones are reported in loess overlying wellweathered till. 

FRYE, J. C., and FENT, O. S., 1947, The late Pleistocene loesses of

central Kansas: Kansas Geol. Survey Bull. 70, pt. 3, pp.

29-52.

Includes numerous references to the old soils associated

with the loesses. 

GILBERT, G. K., 1890, Lake Bonneville: U. S. Geol. Survey

Mon. 1. 

GINZBURG, I. I., 1946, Stages in the weathering of minerals:

Voprosy Mineralog. Geohim., i Petrog. (Tersman Memorial

volume), Akad. Nauk, pp. 122-135. 

GOLDICH, S. S., and BERGQUIST, H. R., 1948, Aluminous lateritic

soil of the Republic of Haiti, W. I.: U. S. Geol. Survey Bull.

954-C.

States that the lateritic soil is paleosol that may have developed in Pliocene or Pleistocene time. 

HARPER, W. <G., Acott, L., and Frahm, E., 1932, Soil Survey

of the Brighton area, Colo.: U. S. Dept. Agr., Bur. Chem.

and Soils [Soil Survey Kept], Ser. 1932, no. 1, 35 pp. 

Describes several of the modern soils as having developed

on more ancient and deep soils. 

HARRISON, J. B. v 1910, The residual earths of British Guiana

commonly termed "laterite": Geol. Mag., new ser., decade 5,

vol. 7, p. 560. 

States that both laterite and kaolin clay have developed.

The difference is attributed to the parent materials; laterite

is derived from basic igneous rocks, whereas kaolin is derived fr,om granitic rocks. 

HUNT, C. B., 1948, Some geological aspects of the problems of

soil genesis and soil classification: Proc. 2d Intemat. Conf.

on Soil Mech. and Foundation Eng., vol. 3, pp. 6-7. 

Pre-Bonneville paleosol in Utah is cited as evidence that

change in climate and other environmental conditions are

important factors in soil genesis.

 Geology of Lake Bonneville, part A, Northern Utah 

Valley. Manuscript in preparation.

Pre-Bonneville paleosol is described in relation to the 

surrounding geology.

HUNT, C. B., CREAMER, A. S., and FAHEY, J. J., 1949, A newly discovered type of clay deposit in Utah: Jour. Washington 

Acad. Sci., vol. 39, pp. 120-122.

A brief description of pre-Bonneville paleosol in Utah. 

Three chemical analyses are given.

JENNY, H., 1941, Factors in soil formation, 281 pp., New York, 

McGraw-Hill Co.

KAY, G. F., 1916, Gumbotil, a new term in Pleistocene geology: 

Science, new ser., vol. 44, pp. 637-638.

Gumbotil on Kansan drift is attributed to advanced 

weathering of till under conditions of poor drainage.

 1931, Classification. and duration of the Pleistocene 

period: Geol. Soc. America Bull., vol. 42, pp. 425-466.

Depth of leaching and degree of weathering of drift 

sheets are used as a basis for estimating relative duration 

of the several glacial and interglacial stages.

KAY, G. F., and PBARCE, J. N., 1920, The origin of gumbotil: 

Jour. Geology, vol. 28, pp. 89-125.

A very complete and pioneering discussion of the origin 

of old soils, demonstrating that the gumbotils on the Nebraskan, Kansan, and Illinoian drift sheets are the result 

chiefly of chemical weathering of the tills.
120 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1949

KING, P. B., 1949, The floor of the Shenandoah Valley: Am. Jour. 

Sci., vol. 247, pp. 73-93.

Describes extensive residuum, a paleosol of residual clay 

that is scores of feet thick.

LAMAR, G. E., GBIM, R. E., and GROGAN, R. M., 1938, Gumbotil as 

a potential source of rotary drilling mud, bonding clay, and 

bleaching clay: Illinois Geol. Survey Inf. Oirc. 39, pp. 1-23. 

States that original till contained large amounts of illite 

minerals, but weathering changed these to minerals of the 

montmorillonite group.

LEIGHTON, M. M., 1923. The differentiation of the drift sheets of 

northwestern Illinois: Jour. Geology, vol. 31, pp. 265-281.

Degree of weathering is used as one of the bases for distinguishing the drift sheets.

 1931, The Peorian loess and the classification of the glacial 

drift sheets of the Mississippi Valley: Jour. Geology, vol. 39, 

pp. 45-53.

Lack of weathering of the Peorian loess is cited as evidence 

that the Peorian was too brief to be regarded as an interglacial stage. lowan is regarded as earliest Wisconsin. 

1936, Geological aspects of the findings of primitive man

near Abilene, Tex.: Medallion Papers 24, Globe, Ariz., 44 pp. 

Weathering of the Durst silts is believed to be Sangamon 

in age.

LEIGHTON, M. M., and MACCUNTOCK, PAUL, 1930, Weathered zones

of the drift sheets of Illinois: Jour. Geology, vol. 38, pp. 28-53.

Describes old soils on Nebraskan, Kansan, and Illinoian

till. Discusses factors controlling rate and type of profile

development.

LEVEKETT, FRANK, 1898a, Weathered zones and soils (Yarmouth 

and Sangamon) between drift sheets: Iowa Acad. Sci. Proc., 

vol. 5, pp. 71-86; Jour. Geology, vol. 6, pp. 171-181, 238-243. 

Introduces names Yarmouth and Sangamon.

 1898b, The Peorian soil and weathered zone (Toronto 

formation?) : Jour. Geology, vol. 6, pp. 244-249. 

Introduces the name Peorian.

 1899, The Illinoian glacial lobe: U. S. Geol. Survey 

Mon. 38.

Recognizes pre-Illinoian weathering Kansan drift 

weathered brown or reddish brown to depths of 30 feet.

 1902, Glacial formations and drainage features of the 

Erie and Ohio Basins: TJ. S. Geol. Survey Mon. 41. 

Includes descriptions of the Sangamon and Peorian soils.

 1909, Weathering and erosion as time measures: Am.

Jour. Sci., 4th ser., vol. 27, pp. 249-268.

Considers differences in weathering and erosion of different drift sheets.

LEVERETT, FRANK, and TAYLOR, F. B., 1915, The Pleistocene of 

Indiana and Michigan and the history of the Great Lakes: 

U. S. Geol. Survey Mon. 53.

Makes brief references to occurrence of buried soils of 

pre-Wisconsin age.

LUGN, A. L., 1935, The Pleistocene geology of Nebraska: Nebraska Geol. Survey Bull. 10, 2d ser., 223 pp.

A comprehensive summary of the Pleistocene geology, including old soils.

 1941, The Pleistocene history of Nebraska: The Compass, 

vol. 22, no. 1, pp. 11-37.

A brief summary of the Pleistocene history, including history of the old soils.

MAUNGA, D. P., 1946, Geochemistry of dispersed nickel and cobalt in the biosphere [in Russian]: Akad. Nauk, Biogeokhim., Lab., Trudy, vol. 8, pp. 73-180.

MntiMANOv, H., 1932, Iskopaemye pochvy v. SSR Armenii: Pochvovedenie, no. 5/6, pp. 576-586. 

Describes a soil buried under lava.

MOHR, E. C. J., 1944, The soils of equatorial regions with special 

reference to the Netherlands East Indies, 766 pp., Ann Arbor, 

Mich., Edwards Bros. Inc. Translated by R. L. Pendleton.

NABOKIH, A. I., 1916, K metodike polevogo i laboratornogo issledovaniia pochvogruntov: Obsch. Selsk. Hoz. luzhnoi Rossii, 

Zapiski, vol. 87, no. 1. 

Describes a succession of Quarternary soil profiles in loess.

NIKTFOROFF, C. C., 1942, Fundamental formula of soil formation : Am. Jour. Sci., vol. 240, pp. 847-866.

Discusses problem of equilibrium and maturity in pedologic age. Maturity is regarded as a dynamic and continuing stage.

 1949, Weathering and soil evolution: Soil Science, vol. 

67, no. 3, pp. 219-230.

Stresses importance of changes in environment in developing soil characteristics.

OGNEV, G. N., 1927, Pochvy uchastka Petergofskogo EstestvennoNauchnogo Instituta: Akad. Nauk, Pochv. Inst., Trudy, 

vol.2.

Describes soils that can be dated by earthworks of 

known age.

PONOMAREV, G. M., and SEDLETZKII, I. D., 1940, o genesise poch 

chernozemnogo i solontzovogo readov v Chernigovskoi 

lesostepi: Akad. Nauk, Pochv. Inst., Trudy, vol. 24, pp. 

241-307.

Describes 10 ancient soils, including podzol, chernozem, 

and rendzina under modern chernozem.

PRASOLOV, L. I., and SOKOLOV, N. N., 1927, Pochvy poimy v raione 

reki Volhova i ozera Ilmenia: Materialy po Issledovaniiu 

Reki Volhova, Akad. Nauk 16.

Describes soils buried by alluvial deposits. 

REICHE, PARRY, 1945, A survey of weathering processes and

products: New Mexico Univ. Pub. Geol. no. 1, 87 pp. 

Ross, C. S., 1943, Clays and soils in relation to geologic processes : Washington Acad. Sci. Jour., vol. 33, pp. 225-235. 

Ross, C. S., and HENDRICKB, S. B., 1945, Minerals of the montmorillonite group, their origin and relation to soils and 

clays: U. S. Geol. Survey Prof. Paper 205-B.

Includes 295 references to papers dealing with clay mineral investigations.

RUPRECHT, J., 1866, Geobotanical investigation of chernozem 

[in Russian]: Prilozhenie t. 10, Zapisok Akad. Nauk, no. 6. 

Cited by N. N. Sokolov as discussing age of soils and 

rates of development. Original not available. 

SCHTJLTZ, C. B., and STOUT, T. M., 1945, Pleistocene loess deposits 

of Nebraska: Am. Jour. Sci., vol. 243, no. 5, pp. 231-244. 

Summary of stratigraphy of loess, including old soils. 

SEDLETZKII, I. D., 1941, The fundamental paragenetic groups of 

minerals in relation to the principal soil types [in Russian]: 

Akad. Nauk, Doklady, new. ser., vol. 31r no. 7. 

Cited by Sedletzkii; original not available.

 1945, Colloidal dispersed mineralogy [in Russian], 114 

pp., Leningrad, Akad. Nauk.

Includes discussion of the possible paragenetic association of certain clay or claylike minerals with the zonal 

soils, for example, beidellite and illite in serozems; montmorillonite, muscovite, sericite, and illite in chestnut soils; 

montmorillonite and illite in chernozems; and kaolinite, 

hydromuscovite, nontronite, and goethite in podzols.

SINIAGIN, I. I., 1946, Microelements in serozem soils [in Russian] : Akad. Nauk, Pochvennyl Inst., Problemy Sovetskogo Pochvovedeniia, vol. 14, pp. 125-137.

SOKOLOV, N. N., 1932, O vozraste i evolintzii pochv v sviazi s 

vozrastom porod i relief a: Akad. Nauk, Pqchv. Inst., Trudy, 

vol. 6, pp. 1-55.

Discusses chronologic and pedologic age of soils and 

reviews literature. Includes 117 references.
PRE-WISCONSIN SOIL IN THE ROCKY MOUNTAIN REfGION 121

STOBIE, R. E., and WEES, W. W., 1941, Key to soil series of 

California, Berkeley, Calif., Assoc. Students Store.

Notes differences in soils of varying degrees of antiquity 

on alluvial fans.

STDEGIS, M. B., and MCMIOHAEL, C. W., 1939, The genesis and 

morphology of the soils of the lower Mississippi Delta: 

Soil Sci. Soc. America Proc., vol. 4, pp. 358-359.

Compares differences in soils on deposits ranging in age 

from Pleistocene to Recent.

TAMM, OIX>F, 1920, Markstudien i det Nord-Svenska Barrskogsomradet: Statens Skogforsokanstalt Medd., Heft 17, no. 3. 

Indicates that the development of pedologic age follows 

a logarithmic curve.

THOBNBUEG, W. D., 1940, Weathered zones and glacial chronology 

in southern Indiana: Jour. Geology, vol. 48, pp. 449-475.

States that mean depth of leaching in young Wisconsin 

end moraines is less than in the older ones and that mean 

depth of leaching in ILLinoian drift is considerably greater 

than in Wisconsin drift.

THORP, J., 1941, Influence of environment on soil formation: 

Soil Sci. Soc. America Proc., vol. 6, pp. 39-46.

TIHEEVA, L. U., 1932, Pogrebennye pochvennye obrazovaniia 

(pochy i torflanniki) chetvertichnogo vremeni v okrestnostiah Leningrada: Akad. Nauk, Pochv. Inst, Trudy, voL 

6, pp. 57-80.

States that diatom flora was used to aid stratigraphic 

determination of paleosols.

VAN BABEN, J., 1931, Properties and constitution of a volcanic 

soil built in 50 years in the East-Indian Archipelago: 

Mededeel. Landbouwhoogeschool, deel 35, verh. 6.

WHJJAMS, B. H, 1945, Sequence of soil profiles in loess: Am. 

Jour. Sci., vol. 243, no. 5, pp. 271-277.

Discusses differences in profile development between soils 

having their development arrested by burial and soils 

of the same antiquity that have continued to develop.

WOODBOTG, W. P., BBOWN, J. S., and BUBBANK, W. S., 1924, Geology 

of the Republic of Haiti, pp. 260-330, Republic of Haiti, 

Dept. Public Works, Port-au-Prince.

States that quartz diorite in northeastern Haiti has 

weathered to kaolin and residual quartz to a depth of 15 

feet and is probably paleosol.

ZEMIATCHENSKII, P. A., 1906, K voprosu o skorosti nekotoryh 

iavlenii vyvetrivaniia: Obsch. Estestvoispytateli, St. Petersburg, Otd. Geol., Trudy, vol. 34, no. 5, pp. 181-190.

States that the Staro-Ladozhskaia fortress of Silurian 

limestone, founded 1116 and abandoned about 1600, developed 10 centimeters of residual rendzinalike soil. 

(Quoted by H. Jenny, Factors of soil formation, New 

York, 1941.)

ZEUNEB, F. E., 1945, The Pleistocene period, its climate, chronology, and faunal succession: Royal Soc. London, Mon. 130, 

322 pp.

 1946, Dating the past, 444 pp., London, Methuen & Co.

Discusses climatology chiefly. Makes reference to red 

clay of the last interglacial period in France.

INDEX

Acknowledgments________________________________ 109 

Alpine formation, clay in, source of.____________...._.._...___ 114-115

Artifacts, occurrence-__________________________.___ 115

Bibliography..__ .-.--.--. . ....................... .. 118-121

Chronologic age of soil_____. ___________. ____________ 110 

Clay, analyses of.......____________________________ 113

Climate, relation of, to paleosol_____. _____. ____________ 117-118 

relation of, to topography__..........______________._.__ 116

Denver Basin, clay in, character..--.-....__________________ 113 

paleosol in, age of...._______._________________ 109,115-116

Fahey, J. J., analyses by....__________________________ 113

Lake Bonneville Basin, clay in, character-._-_.......__________ 113

paleosol in, age of. . .. ..- .... ...-............_ 109,114-115

Middle West, gumbotils of......_ ............................ 111,113,116

Paleopedology, background of. ________________-_____ __ 109 

Paleosol, age... _ _. -_ _- -. ..................... 109,111,114-116

clay layer___________________________ 111-114 

clay layer, analyses of _____________ 113 

compared with Wisconsin soils....._____...... - 116-117

first recognition of.________._____________________ 109 

general character and distribution... ____ 111 

identification of..._______............... ... . .- 117

importance of knowledge of..____________________ ...... 109

lime-enriched layer..__._____ ___ .. 114 

origin and bearing on Pleistocene history.. __ . 117-118 

parent materials_____________-___ -... 111 

trace elements in....______________ 114

Pedologic age of soil, stages. ______________... - 110 

Pleistocene time, relation of, to paleosol._____... 117-118

Gumbotils of Middle West.-----_.................................. 111,113,116 Soil, age of. 109-110

O

Topography, association of paleosol with....___ . 116 

Trace elements in paleosol_________________- .._----_-.--.... 114

Wisconsin soils, compared with paleosoL.___.. . 116-117

123