Iowa Geological Survey.

Annual report ... with accompanying papers, Volume 9 online

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seen are mostly ''second growth " trees. There is very little,
if any, timber cut for export or manufacturing purposes.
There are frequent groves on the prairie farms, planted to
protect the houses and live stock from wintry blasts. The
soft maple {Acer dasycarpum Ehrh.) is the principal tree
planted for this purpose; small groves of black walnut and
evergreen trees are occasionally seen. The forest trees
which most largely contribute to the timber supply are the
white oak {Quercus alba L.), bur oak {Q. nuicroca/rpa Michx.),

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shell-bark hickory {Carya alba Nutt.) and mocker-nut hickory
(C\ tamentosa Nutt.). A few other species contribute more or
less to the wood supply, but the six species above mentioned
largely predominate.

Clematis virginiana L. Virgin's bower. Woody at the base.
Climbing over shrubs, etc., twelve to fifteen feet or more.
Borders of woods and thickets; frequent.

Menispermum canademe L. Moonseed, yellow parilla.
Smooth, shrubby vine, eight to ten feet or more. In alluvial
soil along streams, etc. ; frequent.

Berberis vulgaris L. Common barberry. Shrub four to
six feet high, cultivated as an ornamental shrub; sparingly

Hibiscus milita/iHs Cav. Rose mallow, hibiscus. Plant three
to four feet high, soft woody near the base; flowers large,
flesh- colored, darker at the base, handsome. In alluvial soil
along rivers and streams; frequent.

Tilia americana L. Basswood, white-wood. One of the
larger forest trees in all rich woodlands. Not common; most
frequent along the Cedar river. The flowers yield nectar
abundantly; July.

Xanthoocylum ameHcanum Mill. Prickly ash. In rock and
sandy woods; frequent; shrub six to ten feet high; prickly
and pungently aromatic.

Ptelea tHfoliata L. Wafer-ash, hop-tree. Shrub eight to
twelve feet high; in dry soil, borders of woods, etc.; infre-

Celastrus scandens L. Climbing bittersweet. A twinipg
shrub, climbing over shrubs and small trees in open woods
and thickets; not rare.

Buonymus atropurpureus Jacq. Wahoo. Shrub five to ten
feet; in moist woods; frequent.

Bhammis lanceolata Pursh. Buckhom. Borders of woods
and in thickets along Cedar river; infrequent.

Digitized by



Ceariothus avaericana L. Red-root, Jersey tea. Small,
shrubby plant about two feet high; dry woodlands and sandy
prairies; common.

Viti8 cinerea Engelm. Downy grape. Along the Missis-
sippi and Cedar rivers; not so common as the next.

VUis riparia Michx. River-bank grape, wild grape. In
all woodlands, thickets and fence rows.

Ampelopsis quinquefoliaMiQhx. Virginia creeper. A com-
mon vine in all rich woods; also planted about dwellings for
shade and ornament. In a general way it resembles the
poison ivy, from which, however, it is readily distinguished
by its leaves, which are composed of five leaflets, while those
of the poison ivy are of three leaflets.

Acer Sdccharinum Wang. Hard maple, sugar maple. Medium
to large sized trees; most frequent on the bluffs along the
Mississippi river.

Acer dasycarpum Ehrh. Soft maple, silver maple. One of
the largest trees; most frequent along the Mississippi and
Cedar rivers. Largely planted for groves on the prairies and
for shade along the streets.

Negundo aceroides Moench. Box elder. A small tree fre-
quent along streams, also planted for shade, tod very desir-
able where large trees are not wanted.

Staphylea trifoliata L. Bladder-nut. Shrub eight to ten
feet, in moist woods; not common.

Rhus glabra L. Common sumac. Common in dry soil, four
to six feet, sometimes tree-like ten to twelve feet or more.

Rhus toxicodendron L. Poison ivy. Climbing trees, also
occurring in fence rows and thickets. It is frequently low
and spreading along the ground; common. By contact it pro-
duces very disagreeable skin poisoning in many persons.

Rhus canadensis Marsh. Sweet sumac. Shrub three to
four feet, in sandy soil, often forming broad clumps; rather

Amorpha canescens Nutt. Lead plant. In dry open woods
and sandy prairies; quite frequent; two to three feet high.

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Amorpha Jruticosa L., False indigo. Shrub five to ten
feet; frequent; banks of streams.

Tephrosia virginiana Pres. Goat's rue, cat-gut. Shrubby
plant one to two feet; not rare; in dry soil and sandy prairies.

BoHnia pseudacacia L. Common locust. A small to medium-
sized tree, along roadsides and borders of woods. This other-
wise valuable tree is too subject to the ravages of the locust-
borer, Cystus robinicBf a beautiful yellow-banded beetle com-
mon on the flowers of the golden-rod in September.

Cercis canadensis L. Red bud. Small tree twelve to twenty
feet^ Wooded hillsides along the Mississippi and alluvial
sandy bottom lands of Cedar river; not frequent.

Gymnocladm canadensis Lam. Kentucky coflfee-tree. A
small to medium-sized tree, in alluvial soil along the Missis-
sippi and Cedar rivers; not rare.

Gleditchia triacanthos L. Honey locust. Medium to large-
sized tree, often planted for shade and ornament. Some of
the trees are quite thorny while others are almost or wholly

Prunus americana Marshall. Wild plum. In woodlands along
stream banks, etc.; frequent.

Prunus chicasa Michx. Chickasaw plum. On Muscatine
island near the sand mound; local.

Pruntts virginiana L. Choke cherry. Shrub or frequently
tree-like, eight to twenty feet; in wooded ravines and borders
of woods; frequent.

Prunus serotina Ehrh. Wild black cherry. A medium-sized
forest tree, more or less frequent in all woodlands.

Spircea salicifolia L. Meadow-sweet. Small shrub two to
three feet, in wet soil along the Cedar river; not common.

Physocarpus opulifolius Maxim. Nine-bark. Shrub three to
five feet, in hilly woods along streamlets, etc. ; infrequent.

Rubus occidentalis L. Black raspberry. Frequent in thickets
and fence rows.

Rulms villosus Ait. Blackberry. Borders of woods, thickets,
etc.; common.

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Rubus canadensis L. Low blackberry. Trailing extensively
in neglected fields and borders of woods; fruits sparingly.

Bosa blanda Ait. Wild rose. Rocky, sandy soil; frequent;
two to five feet high.

Bosa wrkamana Porter. Wild rose. Common in dry soil;
one to three feet high.

Rosa ruhiginosa L. Sweetbrier. Along roadsides near old
habitations; escaped from cultivation ; not frequent.

Pyrus coronaria L. Wild crab apple. Tree, frequently
twenty feet high, but generally smaller; often forming small

Pyrus aw£ricana DC. Mountain ash. This has been found
in one or two instances along the border of woods, where the
seeds were probably carried by birds.

Oratcegus coccinea L. Hawthorn, red haw. Border of woods
and in thickets; frequent.

Cratmgus coccinea mollis Torr. and Gray. Red haw. Com-
mon; distinguished among our species by its large, bright
scarlet fruit, one-half inch or more in diameter and edible.

Gratasgus tomentosa L. Hawthorn, red haw. Not common.

Cratoegus crus-galli L. Cockspur thorn. Cedar river region ;
not frequent.

Amelanchier canadensis Torr. and Gray. Juneberry. Small
tree fifteen to twenty feet; in hilly woods; frequent; seldom
has much fruit, although the trees bloom freely in early

Ribes cynosbati L. Prickly gooseberry. Hilly woods; not
common: fruit prickly,

Ribes gracUle Michx. Missouri gooseberry. In open woods,
etc. ; rather frequent.

Ribes floridun L'Her. Wild black currant. Borders of
moist woods; not frequent.

Comus circinata L'Her. Round-leaved dogwood. Shrub
six to eight feet; along Sweetland creek; infrequent.

Comus seHcea L. Kinnikinnik. Wet banks, etc.; shrub,
four to eight feet; frequent.

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Comu8 asperifoUa Michx. Dogwood. Tall shrub, often
tree-like, twelve to fifteen feet high; in sandy soil; frequent.

Oomua alternifolia L. f . Dogwood. Tall shrub, or often
tree-like, ten to fifteen feet high; hilly woods; frequent.

Sambiums canadensis L. Common elderberry. Along fences,
borders of thickets, etc. ; frequent.

Viburnum lentago L. Black haw. Along woodland streams,
etc.; shrub, or often tree-like, six to fifteen feet high; not

Lonicera glauca Hill. Honeysuckle. Hilly woods and rocky
ledges; frequent.

DiervUla t/rifida Moench. Bush honeysuckle. Rough or
stony hillsides at Wild Cat Den; local.

Fraayinus americana L. White ash. Medium to large-sized
trees; frequent, but becoming scarcer.

Fraxinus pubesoens Lam. Red ash. Creek bottoms; prob-
ably infrequent; collected but once.

Praayinus vvridis Michx. f. Green ash. Along wooded
streams; frequent; the most common ash.

Fraxinus samhucifolia Lam. ash. Along streams,
etc. ; not common.

Tecoma radicans Juss. Trumpet-creeper. Has escaped from
cultivation more or less about old habitations.

Catalpa speciosa Warder, and probably unintentionally with it
C. Jngnonoides Walt., have been largely grown and planted,
but no escapes have so far been noted.

Ulmus fulva Michx. Slippery elm. In rich woods; not

Ulmus americana L. White elm. A very common and large
tree in all river and creek bottom lands.

Celtis occidentalis L. Hackberry. Along streams in low
ground; not common.

Madura aurantiaca Nutt. Osage orange. Largely used for
hedges; self -established specimens are seldom seen.

Morus rubra L. Red mulberry. Small tree fifteen to thirty
feet high; not common; more frequent along Cedar river.

Digitized by



Platanus occidentalis L. Sycamore. Often a large tree; in
alluvial soil along streams; not common.

Juglans cinerea L. Butternut. A rather small tree; rich
woods near streams; not common.

Juglans nigra L. Black walnut. In rich soil along streams;
frequently planted along roadsides near farm houses; native
trees of much size have become rare.

Gary a olivceformis Nutt. Pecan-nut. Infrequent; a few
trees near Wyoming Hill, and in the ** big timber'' below Mus-
catine city, along the Mississippi.

Gary a alba Nutt. Shell-bark hickory. In all upland woods;
the most common of the hickories; not many large trees exist
any more.

Gary a sulcata Nutt. Big shell-bark hickory. In the **big
timber" below Muscatine, and less frequently along Cedar

Carya tomentosa Nutt. Mocker-nut hickory. In nearly all
upland woods, and rather frequent.

Carya amara Nutt. Bitter-nut hickory. River and creek
bottom land; sometimes on upland; frequent.

Betula nigra L. Red birch. A small to medium-sized tree
along streams; rather common.

Corylus americana Walt. Hazelnut. Common in open
thickets and borders of woods; two to six feet high.

Ostrya virginica Willd. Iron wood. Hilly woods frequent;
small tree. ^

Carpinus caroliniana Walter. Water beech. A small tree
along woodland streams; not common.

Quercus alba L. White oak. One of the most common oaks;
not many of the larger native trees are left standing.

Quercus macrocarpa Michx. Bur oak. Common in low and
on high ground; very large trees not frequent.

Quercus bicolor Willd. Swamp White oak. In low ground
along streams; frequent.

Quercus muhlenbergii Engelm. Chestnut oak. Hilly woods;
not frequent.

Digitized by



Quercua rubra K Red oak. A very common tree in all
upland woods.

Qusrcus coccinea Wang. Scarlet oak. An abundant upland

Quercus palmtris Du Roi. Pin oak. Common in wet soil
along the Mississippi and Cedar rivers.

Quercus imbriearia Mich. Shingle oak. A few small trees
only in Cedar township.

/Salix nigra Marsh. Black willow. Along streams, a small
4o medium sized tree.

Sallv amygdaloides Anders. Black willow. With the
former and very similar.

ISalix alba vitellina Koch. Yellow willow. Small to medium
sized tree with yellow branches and twigs; cultivated and self
planted from detached twigs.

Salix longifolia Muhl. Long leaved willow. Very common
along the shores of the larger streams, six to twelve feet.

Salix discolor Muhl. Pussy willow. Along the smaller
streams and wet places; five to ten feet or more high.

Salix humilis Marsh. Prairie willow. In dry soil, two to
four feet high; not frequent.

Salix cordata Muhl. Heart-leaved willow. Along streams,
etc., five to ten feet high; frequent.

Salix purpurea L. Purple willow. Bank of Mad creek,
near Muscatine city, four to six feet high; local.

Populua tremuloides Michx. Quaking aspen. A small tree
in moist woods; not common.

FopulusgrandldentataMichx. Large-toothed aspen. Medium
sized tree, in rich, moist woods; not common.

Populns monilifera Ait. Cotton- wood. Along streams; fre-
quently a large tree.

Pinus strobus L. White pine. On rugged hills at Wild Cat
Den, twelve miles above Muscatine; some of the trees still
standing are two feet or more in diameter.

32 0*Bep

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Junipems vii^giaiaiia L. Red cedar. . Represented only by

scraggy specimens on rock ledges;. Wyoming Hill, Wild Cat

Den, etc.


Gray's Manual, sixth edition, has been followed in the
preparation of the above list.

I wish to express my thanks here to Prof. T. H. Macbride, for
help and suggestions, and to Prof. L. H. Pammel for compar-
ing specimens of Crataegus and Fraxinus, at the Missouri
Botanical Gardens; and to C. R. Ball for determining speci-
mens of Salix.

From the loess described on page 358, the following fossils hare been collected, (Identified
by Bhlmek):

naietna oceuUa Say.

Vdtoala cineera Say.

Polyvyra mulUUneata (Bay) PUs. (?)

PoUygifra monodon (Bock) PUs.

StrobOofM Virgo Plls.

Bifidarla peniodtm (Saj) St.

Pupa muacorum L.

CoefiUeapa lubriea (Mttll) P. & J. ^

PuramidulaaUernala (Say) Plls.

Pyramidula penpectiva (Bay) Plls.

Pyramidula strlaUlla (knth) Plls.

Sueeinsa obUqua Say.

Sueelnea awura Say.

Succtnea ovalia Old.

Limnaa eaperaUi Say .

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38 G Rep

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Introduction 393

Topography 394

Constructional Reliefs 395

lowan Drift Plains ^ 396

The Paha 395

lUinoian.and Kansan Drift Plains 399

Pluvial Plains v 401

Erosional Beliefs 401

Causes and Conditions 401

Thellllnoian 408

The Kansan 410

Drainage 410

Wapsipinicon River 411

Rock and Walnut Creeks 413

Mud Creek 413

Other affluents of Wapsipinicon 415

Affluents of Mississippi 415

Mississippi River 417

Terraces 418

Rock Island Rapids 418

History of Drainage 419

Stratigraphy 422

Taxonomic relations 422

Geological Formations 423

Silurian 423

Gower Stage 423

Le Claire Stone 42S

Anamosa Stone. 424

Relation of Le Claire and Anamosa 429

Sections of Gower 430

Le Claire. 432

Anamosa 432

Intermediate Tyi^s 430

Digitized by




Devonian 440

Wapsipinicon 440

Otis .-440

Independence 442

Lower Davenport 443

Brecciation of Lower Davenport 444

Upper Davenport 447

Fauna of Upper Davenport t . . . 450

Sections of Wapsipinicon 452

Cedar Valley 457

General Description * 457

Sections 460

Carboniferous 463

Surface Distribution 463

Sections 466

Geest 469

Pleistocene 471

Tazonomic relations 471'

Pre-Kansan 472

Af tonian 474

Kansan 475

Yarmouth 478

Illinolan 480

Sangamon 482

lo wan 483

lowan Loess 484

Red Loam 486

Loess Sands 488 .

Preglacial Surface ; 492

Economic Products 494

Coal : 498

Building Stone , 496

Silurian 496

Devonian 497

Lime ; !. 499

Clays 499

Carboniferous 499

Loess 501

Road Materials 503

Spils 503

Water Supply 604

Artesian Wells 505

Acknowledgments 514

Appendix— Table of Wells 514

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Scott county is not only one of the most populous and
wealthy of the counties of Iowa, but it is rich also in geolog-
ical phenomena of peculiar interest and importance. Although
it comprises an area of onjy 447 square miles, there outcrop
within its borders the consolidated sediments of various
stages of three great geological series — the Silurian, the
Devonian and the Carboniferous. In a number of localities
these are of special industrial value, and furnish mines of
coal and clay and quarries of building stone and lime. As the
frontiers of three geological systems of indurated rocks lie
within the county, so within the same narrow limits the bor-
ders meet of three great sheets of drift, which record three dis-
tinct invasions of continental glaciers in late geological time.
In various forms of topography, due to the action of different
geological agencies, Scott county is equally rich. Unscored
plains of alluvium and of glacial drift, past plains now
maturely dissected by valleys of erosion, rocky gorges of
young rivers, billowy hills of frontal loess moraines, — all these
varied contours give the landscape a diversity of beauty and
a wealth of geologic interest.

Few counties in Iowa ofifer better facilities for geological
investigation. Fronting on the Mississippi and bounded on
the north by the Wapsipinicon, the eastern and northern
townships have been so far dissected by these master streams
and their tributaries that numerous exposures are aflForded of
the indurated rocks as well as the unconsolidated Pleistocene
deposits. The excavations made in the years since the early

84 O Rep 393

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settlement of the county have added to the natural sections
of gorges, scarps and hillside ledges, many artificial geolog-
ical sections in mines, wells, quarries, and railway cuttings.

It is not strange, therefore, that Scott county long since
attracted the attention of geologists. In the course of the
early surveys of the Mississippi valley made by David Dale
Owen* the geological areas of the county were roughly
delineated, and fossils were described and figured from Daven-
port and Buffalo.

The survey of Hall and Whitneyt describes accurately the
*' limestone of the Rapids of LeClaire," and devotes twelve
or more pages to the discussion of the higher rocks of the
county. Out of thirty-eight species described by this survey
from the Devonian, eighteen are listed from Scott coimty and
six from the opposite bank of the Mississippi at Rock Island.
Since that time the fossils of the county have been patiently
collected and carefully preserved, as the fine cabinets of the
Davenport Academy of Science, Rev. Dr. W. H. Barris and
Mr. Asa Tiflfany testify. Their rich fauna has been described
by Barris, by Hall, by Worthen, by Meek, and by Lindabl.
Aspects of the glacial deposits of the county have been
treated by McGee, McWorther, Pratt, Calvin, Bain, Leverett,
and Udden, and of the older formations by Barris, Tiffany,
Calvin, Udden, Norton and Keyes.


The topography of Scott county is due to the action of
many forces acting through vast periods of time, and it is not
always an easy matter to disentangle the complex causes of
its various forms of relief. All topographic forms may be
divided into two classes, those of construction and those of
erosion. To the former class belong the hills of the lowan
frontier, some aggraded valley floors, and the uneroded rem-
nants of the drift plains. To the latter class belong all other
reliefs in the county; for, with these exceptions, every hill

*Bept. Oeol. Surv. of WUconsln, Iowa and Minnesota, Philadelphia, 1808.
tOeol. of Iowa (Hall), toI. I, p. 78 seq , p. 278 srq. 1858.

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and valley, ^ery bluff and precipice, strath and streamway
is due to the corrasion of running water in rill and river, to
rain wash, and all the various processes known as weathering.


lowan Drift Flaina. — In northeastern Iowa there is associ-
ated with the lowan drift sheet a topography which is strik-
ingly distinct and in part entirely unique. There is the
bowlder strewn drift plain, with its gentle undulations, its
sags and swales due to initial inequalities in the ice-moulded
surface of the till, its drainage so immature that storm water
lingers upon it in sloughs and shallow lakelets, its soil peaty
and black because of the rapid accumulation of humus con-
sequent on the comparative ineflBciency of the agents which,
in mature districts, remove it almost or quite as rapidly as it
forms. The lowan drift plain is but slightly represented in
Scott county. It comes well down to the Wapsipinicon flood
plain on the Clinton county side, but to the south of the ^ood
plain it occurs only in a narrow belt in the northern part of
Winfield and Butler townships; and over a considerable por-
tion of this belt, this drift-plain is in part effaced by the
peculiar hills characteristic of lowan areas which are next to
be noticed.

Tfie Paha. —Paha are boat-shaped hills or long narrow ridges
with northwest-southeast trend, and are composed in part of
water-laid sand and silt and in part of ice-moulded till. These
unique relief forms are found in Iowa and Illinois along the
entire southern margin of the lowan ice invasion. They are
not confined, however, to the limit of its advance, but occupy
a large part of the area of its southern extension, the *' land
of the paha" as it has been termed by McGee* to whose first
descriptions and interpretations but little has been added by
later students.

The '* land of the paha " lies largely to the north and west
of Scott county, and the great paha hills and ridges of Cedar

^Pleistocene History of Northeastern Iowa. 11th Innnal Bept , U. 9. Geol. Bury.

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and Jones are here but feebly represented. Still, the paha of
the lowan frontier, which stretches from the east bank of mud
creek north of Allen Grove, through Winfield and Butler
townships, north of Donahue and Long Grove and through
Walnut Grove, and on nearly to the Mississippi at Princeton,
are typical in form, in orientation and in composition and
structure. That the paha are hills of construction, and are
not the wasted remnants of a once level upland, is best seen
from a station a little to the south of their belt. Looking
from such a station toward the south, the east, or the west,
one sees everywhere a dissected upland carved into valleys
and hills of erosion. Everywhere an even sky line, the
original level of the upland meets the eye. But turning to
the north the sky line changes. It undulates in gently convex
curves which rise definitely above the surrounding region.
The paha here overide the upland for a narrow zone along its
northern margin. This is seen more clearly by contrast where-
ever, as in section 26, Butler township, the paha are inter-
rupted for a short distance and the upland descends unmodified
to the Wapsipinicon flood plain. In some of the adjacent
sections the paha abut against the steep northern edge of the
upland, while in Winfield aild Allen Grove townships, where
the upland descends gently to the north, they are built in part
upon it and in part on the lowan drift plain which continues
the gentle descent to the Wapsipinicon flood plain. But
whether they occur on the bowlder dotted lowan drift plain
or override the margin of the loess mantled Illinoian upland,
in all cases their contours and their trend are not undet the
control of any streams which might be supposed to have
carved them out of an initial land mass. The paha are indif-
ferent to any erosional divides. They may indeed form
divides between stream ways, but here the streams are under

the control of the hills, and have been diverted from their
arborescent courses to courses parallel, and with the north-
west-southeast trend so characteristic of paha regions. Or

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the paha may lie athwart the natural divides, as in section 19
of Butler and 24 of Winfleld townships.

In shape the paha may assume the forms of long, low
swells, sometimes simple and comparatively even topped, but
usually complex and lobate, the crest line rising in long, boat-
shaped sumniits, and falling in low, broadly concave cols. Of

FfO. 41. Paha near St Aqq*8 church, northeast of Long Grove.

these the Saint Ann pahji (Fig. 41), north of Long Grove, is
an example. Again, the dolphin-backed eminences may be

Online LibraryIowa Geological SurveyAnnual report ... with accompanying papers, Volume 9 → online text (page 29 of 43)