Late Pleistocene Diatoms 

From the Trempealeau 

Valley, Wisconsin 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 523-A 

Late Pleistocene Diatoms 

From the Trempealeau 

Valley, Wisconsin 

By GEORGE W. ANDREWS 

CONTRIBUTIONS TO PALEONTOLOGY 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 523-A 

A late Pleistocene diatom assemblage 

from west-central Wisconsin and its 

paleoecologic and stratigraphic 

significance 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1966 
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary 

GEOLOGICAL SURVEY 

William T. Pecora, Director 

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

Washington, D.C. 20402 - Price 40¢ (paper cover) 
CONTENTS 

~~::;;::~;;~:~::::::::::::::::::::::::::::::::::::: peology __________________________________________ _ 

Regional relationships __________________________ _ 

Trempealeau Valley terraces ____________________ _ 

Quaternary ge~logic history _____________________ _ 

!Hixton diatomite deposit ___________________________ _ 

Location ______________________________________ _ 

Page 

Al 

1 

2 

2 

3 

4 

5 

5 

Hixton diatomite deposit-Continued Stratigraphy __________________________________ _ 

Radiocarbon chronology ________________________ _ 

Diatom assemblage ________________________________ _ 

Sample preparation ____________________________ _ 

Paleoecologic interpretation _____________________ _ 

Systematic descriptions _____________________________ _ 

References cited ___________________________________ _ 

Index ____________________________________________ _ 

ILLUSTRATIONS 

~LATES J-3. 

I FIGURE 1. 

2. 

3. 

[Plates follow p. A27] 

Diatoms from the Hixton deposit, Trempealeau Valley. 

Index map showing location and regional relationships of the Trempealeau Valley area ________ - __ -- ______ --

Map of the Trempealeau Valley area, west-central Wisconsin ____________ -- ___________ -- ____ -------------

Profiles of the modern Trempealeau River valley and three Pleistocene terrace treads _____________________ _ 

4. Location map of the Hixton diatomite deposit and its relation to the older Arcadia Terrace ________________ _ 

TABLE 

Page 

A5 

7 

7 

7 

8 

10 

23 

25 

Page 

A2 

3 

4 

6 

Page 

TABLE 1. Relative abundance, temperature, and pH range of diatoms from the Hixton diatomite_____________________ AS 

III 

CONTRIBUTIONS TO PALEONTOLOGY 

LATE PLEISTOCENE DIATOMS FROM THE TREMPEALEAU VALLEY, WISCONSIN 

By GEORGE w. ANDREWS 

ABSTRACT 

The Trempealeau Valley trends in a generally southwestward 

,direction across the Driftless Area of west-central Wisconsin 

!between the central Wisconsin lowland and the Mississippi 

'Valley. It contains an upper Pleistocene alluvial fill. Rem-

)nants of three terraces have been recognized in the valley : the 

/Cortland Terrace of probable early Wisconsin (pre-Cary) age, 

;the Arcadia Terrace of Cary age, and the Whitehall Terrace 

10f Mankato age. The two younger terraces result from valley 

l

alluviation during the Cary and Mankato glacial maxima. Near 

Hixton, Wis., a 6-inch bed of diatomite occurs on the Whitehall 

!

Terrace surface. It is overlain by peat and underlain by a 

deposit consisting of organic debris and large fragments of 

l

spruce, which has a radiocarbon age of approximately 11,000 

,years B.P. This age suggests that the Hixton diatomite was 

!deposited during the Valders Stade of the Wisconsin Glaciation. 

I Seventy-three species and varieties of fresh-water diatoms I 

l

have be:n re<;og~ized in ~he Hixton deposit. Navicula rotunda 

and Eptthemw trregulans are described as new species in this 

/report. The diatom assemblage is dominated by Fragila,ria 

1construens var. venter, a minute diatom seldom exceeding 15 

/microns in length. The areal distribution of the deposit, the 

!stratigraphy, and the diatom assemblage suggest deposition in 

ja shallow pond; the composition of the diatom assemblage sug-

!gests deposition in cool water, but the evidence is inconclusive. 

INTRODUCTION 

, General statement.-The Trempealeau River drains 

'l

1

part of th? Driftless Area in west-~entral Wisconsin. 

Its source Is near the northern margin of the Driftless 

! Area at the edge of the glaciated Central Low land 

!physiographic province. Although the bedrock divide 

!between the Driftless Area and the Central Lowland is 

!breached in the vicinity of the headwaters of the 

1

Trempealeau River, the modern drainage is confined to 

lt~e Driftless ~rea by a low divide on the valley allul

vium. The river flows, somewhat circuitously, south-

,westward to join the Mississippi River a short distance 

/downstream from Winona, Minn. The valley is nearly 

160 miles long. The Trempealeau River drainage basin 

is bounded on the north by the drainage basin of the 

Buffalo River and on the south by that of the Black 

River. The location and regional relations of the area 

under consideration are shown in figures 1 and 2. 

The Trempealeau Valley contains remnants of three 

Pleistocene terraces, which have not been previously 

studied. The only allusion to these deposits in the 

geologic literature, as far as known, is that of Chamberlin and Salisbury (1885, p. 310) who stated: "On the 

Trempealeau River are also fine terraces carved mainly 

from the finer alluvial constituents, this valley apparently not having been one of the main channels of 

glacial discharge." 

A small deposit of diatomite on one of these terraces 

has been djscovered recently near Hixton, Wis. This 

diatomite is, fortunately, associated with considerable 

organic debris, chiefly peat and wood, which has been 

dated by the radiocarbon 1nethod. The Hixton diatom 

assemblage is, therefore, important as a paleoecological 

indicator of known age in the local Quaternary sequence. The radiocarbon age of the deposit is also of 

value in relating the local sequence of the Trempealeau 

Valley to the late Quaternary history of the region. 

8urrvmary of investigation.-This study has been conducted with a two-fold emphasis. First, the diatom 

assmnblage of the diatomite near Hixton was studied in 

detail to evaluate its paleoecological significance. Second, a reconnaissance survey was made of the Trempealeau Valley terraces so that the geologic setting 

of the Hixton diatmnite might be better understood. 

The exa:..nination of the terraces has been primarily of 

a geomorphic nature, and neither the lithology nor the 

areal distribution of the terraces have been studied in 

detail. The Hixton diatomite was initially sampled 

in the summer of 1960. Additional samples, including 

those for radiocarbon dating, were taken in 1963. 

Observations on the geology of the deposit were made 

in 1960 and 1963. 

Acknmoledgments.-The occurrence of diatomite 

near Hixton, Wis., was first called to the attention of 

the writer by George F. Hanson, State Geologist of 

Wisconsin. Mr. Herman Krome of Hixton kindly 

assisted in collecting samples from his property on two 

occasiOns. Thanks are expressed to Kenneth E. LohAl 
A2 CONTRIBUTIONS TO PALEONTOLOGY 

man, U.S. Geological Survey, for his helpful advice 

in the preparation of this report and for his critical 

review of the manuscript. The suggestions of Charles 

S. Denny, U.S. Geological Survey, who reviewed the 

manuscript, are also sincerely appreciated. 

GEOLOGY 

REGIONAL RELATIONSHIPS 

The Trempealeau River flows through a bedrock valley cut in sandstones of Late Cambrian age. Several 

formations of this age are exposed in the area; all are 

basically fine- to medium-grained friable sandstones 

having only slight variations in their resistance to erosion. These poorly cemented sandstones disintegrate 

readily under the humid weathering conditions of the 

region and provide abundant sediment for transport by 

the stream. The Upper Cambrian rocks were formerly 

overlain by the resistant Oneota Dolomite of Early 

Ordovician age throughout the region. This dolomite 

was, however, completely removed by erosion from the 

bluffs surrounding the upper part of the Trempealeau 

Valley. It still caps the bluffs on either side of the valley as one approaches the Mississippi River. The Oneota Dolomite has probably contributed a small amount 

of chert to the Trempealeau Valley sediments, but it has 

not been a major source of sediment for the valley. 

The Trempealeau Valley crosses the northern part of 

the Driftless Area, an unglaciated region in southwestern Wisconsin and smal1er adjacent parts of Minnesota, Iowa, and Illinois. There is no conclusive evidence that the Drift1ess Area was ever covered by ice 

during the Pleistocene Epoch although it is surrounded 

by glacial drift deposits. The area was approached at 

different times by various ice sheets moving in different 

directions, but it was never completely surrounded at 

any time by a single ice sheet. The Driftless Area does 

contain drift in the sense of loess and vailey findings 

of outwash. The loess was blown in from nearby glaciated areas, mainly those to the west, probably in large 

part from Mississippi Valley outwash trains. The outwash was deposited from melt water flowing from ice 

sheets located to the north and east. 

The age of the drift shown in figure 1 on the west 

boundary of the Driftless Area near the Trempealeau 

Valley is uncertain. This scattered deposit is probably 

of pre-Wisconsin age, and it seems to have little bearing 

on the problem under discussion. 

The pre-Cary drift deposits of central Wisconsin, 

northeast of the headwaters of the Trempealeau River, 

were described by Weidman (1907, p. 433-488) who attributed them to three separate glacial events. Hole 

( 1943), on the basis of the mineralogy of these "old 

drifts" and a study of the soils formed upon them, con47' 

46' 

45' 

92' 91' 90' 89' 88' 87' 

~-----r1 

_, 

I 

I I I 

... _ MICHIGAN I 

c a ry 

FIGURE 1.-Location and regional relationships of the 

Trempealeau Valley area (shaded). 

eluded that all these deposits should be assigned to a 

single glacial event not older than Wisconsin in age. A 

radiocarbon date of more than 45,000 years for organic 

material subjacent to the "old drift" near Marshfield, 

Wis., has been published by Black ( 1959). The "old 

drift" is now considered to be pre-Cary in age but related to a single early ice advance during the Wisconsin 

Glaciation. The outer margin of the "old drift" passes 

close to Merrillan, Wis., immediately northeast of the 

breach in the bedrock at the head of the Trempealeau 

Valley. This drift is thin at the margin and does not 

form conspicuous topographic features. 

The most recent advance into the area was made by 

the Cary glacier; the Chippewa lobe reached a position 

about 40 miles north of the head of the Trempealeau 

Valley. The Cary ice sheet also deposited a valley train 

of outwash in the Mississippi Valley, probably a factor 

of more importance to the history of the Trempealeau 

Valley. Later ice advances did not reach central Wisconsin. A valley train of outwash from the Mankato 

glacier was deposited in the Mississippi Valley, and the 

probable effects of this event are discussed later in this 

paper. 

The entire Trempealeau Valley area is mantled by 

loess of Pleistocene age. These deposits have never been 

adequately studied, and their specific age is not known. 

The loess is negligible in the upper part of the Trempealeau Valley, but it abruptly increases in thickness 
LATE PLEISTOCENE DIATOMS, TREMPEALEAU VALLEY, WISCONSIN A3 

5 0 5 10 MILES 

R.6W. 91° R.4W. 

~--, 

olo 

U•U 

T. 

24 

N. 

T. 

18 

N. 

~~~ ~~------------------~---~~~--------------~ 

es·ls 

~:g 

....:::1' Sparta 

0 

! 

I 

FIGURE 2.-The Trempealeau Valley area, west-central Wisconsin. Shaded areas indicate valleys filled by glacial outwash. 

I 

oward the Mississippi Valley. It may exceed 10 feet 

n thickness on parts of the upland near the western 

nargin of the area. Hence, Pleistocene loess is an imortant source of sediment in the lower part of the 

frrempealeau watershed. 

! 

TREMPEALEAU VALLEY TERRACES 

. Three terrace levels are recognizable in th~ Trempealeau Valley, and they show varying degrees of promi-

,nence. The terraces are important keys to the Pleistobene geologic history of the valley, and a discussion of 

ese features is fundamental to an understanding of 

1e occurrence of the Hixton diatomite. Profiles of the 

errace levels of the Trempealeau Valley are compared 

! ith a profile of the modern valley floor in figure 3. 

The highest (and hence, oldest) terrace observed in 

the valley is herein termed the Cortland Terrace for its 

!occurrence in the Cortland School District, Arcadia 

fl'ownship, Trempealeau County, Wis. This terrace is 

~prominent topographic feature in sees. 16, 17, and 21, 

!T. 20 N., R. 10 W., where the terrace tread has an altirude of about 795 feet. The occurrence of the Cortland 

Terrace at this locality is remarkable in that it extends 

nearly across the comparatively narrow valley; the 

modern river is confined to a narrow gap at the northwest valley wall. The river must have maintained its 

course at this point throughout post-Cortland time, but 

the reason for this is obscure. A few additional old terrace remnants that seem to correlate with the Cortland 

level have been noted farther up the Trempealeau Valley. A terrace level or erosion surface at an altitude 

of a!bout 775 feet occurs immediately southeast of Independence, Wis. A deeply eroded probable terrace level 

with an altitude of about 980 feet occurs south and east 

of Taylor, Wis., and covers an area of several square 

miles at a comparatively wide part of the valley. Other 

probable remnants of this terrace have been noted southeast of Hixton at an altitude of about 1,020 feet and 

near the head of the Trempealeau Valley at an altitude 

of about 1,040 feet. The nature of the deposits at these 

localities needs confirmation in the field. Other remnants of the Cortland Terrace could probably be identified by field mapping. 

The Cortland Terrace is thought to be a valley-train 

• 
A4 CONTRIBUTIONS TO PALEONTOLOGY 

1100~' ----------------------------------------------------------------------------------------~ 

__J1000' 

w 

> 

:':J 2 

c <( (]) 

w (.) 

(/) ro 

z 900' .s <( <( 

w 

:2: 

w 

> 

0 

~ 800' 

w 

0 

::l 

f--

5 

<( 700' 

---- -_,_--

---

0 5 MILES 

600'~----------------------------------------------------------------------------------------~ 

FIGURE 3.-Profiles of the mod.ern Trempealeau River valley and three Pleistocene terrace treads. Ticks on profiles show altitudes 

from topographic maps; profile lines dashed where inferred. 

terrace related to the pre-Cary Wisconsin Glaciation 

of central Wisconsin. Melt water from this ice sheet 

probably breached the headwater divide of the Trempealeau Valley. The Cortland Terrace has no recognized counterpart in the Mississippi Valley. 

The middle terraee of the Trempealeau Valley is by 

far the most prominent and is here named the Areadia 

Terrace from the remnant which occurs at an altitude 

of about 775 feet immediately south of Arcadia, Trempealeau County, Wis. The Arcadia Terrace ranges in 

altitude from about 740 feet at the mouth of the Trempealeau Valley to about 940 feet near the head of the 

valley, where it n1erges imperceptibly with the modern 

flood plain. The terrace is not eontinuous along the 

valley, but its remnants are so nmnerous that they ean 

be readily eorrelated. The terrace deposit was cut by 

subsequent erosion whieh formed a prominent esearpment. Beeause of the sandy nature of the deposit, this 

esearpment has retained its original erosional form, 

1naking the Areadia Terrace by far the Inost obvious one 

in the valley. The Arcadia Terrace is thought to be 

the disseeted remnant of an alluvial plain of Cary age, 

formed perhaps when the Trempealeau Valley was 

da1nmed by Cary outwash in the Mississippi Valley. 

Some of the sand in the Areadia Terraee is probably 

an aceumu1ation of loeally derived debris, but mueh of 

it may a1so have been carried through the breaehed 

divide at the head of the valley by Cary melt water. 

The Arcadia Terraee is thought to correlate with the 

terrace remnant ( alt about 725 ft) of probable Cary age 

in the Mississippi Valley about 1 mile east of the mouth 

of the Trempealeau Val'ley. 

The lowest (and youngest) te.rraee observed in the 

Trempealeau Valley is here designated as the Whitehall 

Terraee for its occurrence at an altitude of about 810 feet 

at Whitehall, Trempealeau County, Wis. The Whitehall Terrace is low and less prominent than the Arcadia 

Terrace. It ranges in altitude from about 695 feet at 

Dodge to about 840 feet at a point between Whitehall 

and Blair, where it becomes so low aJnd forms such a 

weak escarpment that it cannot be easily distinguished 

from the modern flood plain. The Hixton diatomite 

was deposited in a shallow pond on the Whitehall Terrace, which was more lilmly an erosional than a depositional surface at Hixton. The Whitehall Terrace is 

apparently the dissected remnant of an alluvial plain 

formed by the damming of the outlet of the Trempealeau 

Valley by Mankato outwash in the Mississippi Valley. 

The terrace deposits are comparatively silty and are 

probably aU of local origin, derived mainly from 

Ca1nbrian sandstone, Pleistocene Arcadia Terrace sediments, and Pleistocene loess. A remnant of this outwash now forms a terrace at 3!11 altitude of about 680 

feet near the confluence of the Trempealeau and Mississippi Rivers. This remnant in the Mississippi Valley is 

probably of Mankato age. 

QUATERNARY GEOLOGIC HISTOR·Y 

The preglacial eonfiguration of the Trempealeau 

Valley is poorly known, for the depth of the bedrock 

valley floor has never been determined. No bedrock 

c.rops out in the eenter of the valley, so it may be assumed 

that the preglaeial valley was somewhat deeper than the 

modern valley. No Quaternary drainage changes are 

evident.. The earliest event of Quaternary history 

recorded in the present topography was the breaching 

of the divides at the headwaters of the Trempealeau 
LATE PLEISTOCENE DIATOMS, TREMPEALEAU VALLEY, WISCONSIN AS 

River and Pigeon Creek. These divides had b~en 

formed on the relatively nonresistant Upper Cambrian 

sandstones of the region, and they had undoubtedly b~en 

lowered considerably by normal processes of eroswn 

prior to their erosion by glacial melt water.. These 

divides were probably eroded by melt water from t~e 

ice that deposited the pre-Cary drift of central 1VIsconsin. This ice sheet moved very close to the headwaters area (fig. 2). Perhaps the melt water from this 

ice sheet transported outwash debris that formed the 

hirrh Cortland Terrace in the va11ey. 

The next Pleistocene event that can be recognized in 

the Trempealeau Valley is the deposition of the Arcadia 

Terrace sediments of Cary age. The level of the terrace was controlled by the level of the Cary valley train 

in the Mississippi Valley, which reached an altitude 

of at least 725 feet. Some of the sand in the Arcadia 

Terntee deposits is undoubtedly of local derivation, but 

much of it may have been swept over the low divide at 

the head of the Trempealeau Valley by Cary melt water. 

The Arcadia surface converges toward the level of the 

modern flood plain at the head of the valley. The terrace is a prominent topographic feature at the site of 

the Hixton diatomite deposit, and it continues to the 

mouth of the valley. The Arcadia Terrace was largely 

formed by post-Cary, pre-Two Creeks erosion, and it 

has been modified by more recent erosion. 

DurinO' the Mankato Stade the building of another 

outwr~sh"' train in the Mississippi Valley raised the 

Trempealeau Valley outlet to an altitude of about 680 

feet. The damming of the Trempealeau VaHey resulted 

in the ponding of its lower reaches and perhaps ~n 

accumulation of a small amount of silty and orgamc 

debris. In the middle reaches of the valley, deposition 

of locally derived sand and silt produced the 1Vhitehall 

Terrace deposit. At the diatomite locality near H~xton 

lateral erosion by a meandering stream was the dommant 

process during the Mankato Stade. 

PoE.t-Mankato erosion in the Mississippi Valley has 

reduced the outlet of the Trempealeau Valley to an altitude of about 650 feet. The outlet may have even been 

lower than this during late glacial and early postglac~al 

intervals, but evidence is lacking. The pond deposits 

of the lower Trempealeau Valley have been almost 

obliterated by erosion. The more sandy deposits in the 

centrnJ part of the valley have been dissected to form 

the 1Vhitehall Terrace. In Post-Mankato time only 

slight erosion and deposition appear to have taken place 

in the upper part of the valley, where the valley floor 

has remained at about the same level since the Mankato 

Stade. The peat and diatomite of the Hixton deposit, 

which occur only a few feet above the channel of the 

modern stream, were laid down in a depression on the 

Mankato surface during the Two Creeks Interstade and 

the Valders Stade. 

HIXTON DIATOMITE DEPOSIT 

LOCATION 

The diatomite deposit studied for this report is approximately a quarter mile south of the center of the 

villao·e of Hixton Wis., a short distance southwest of b ' 

State Highway 27 and northwest of the Green Bay and 

vVestern Railroad tracks. The specific location is the 

Ny2SW%SE% sec. 17, T. 22 N., R. 5 W., Blair quadrangle, .Tackson County, '\Vis. The location of the deposit and its relation to the nearby Arcadia Terrace and 

the modern Trempealeau River are shown in figure 4. 

The diatomite deposit is found underlying the surface 

of a semicircular reentrant cut by a meandering stream 

in the Arcadia Terrace (Cary) sediments on the south 

side of the Trempealeau Valley. The erosion surface 

beneath the deposit is thought to be related to the same 

cycle during which the Whitehall Terrace (Mankato) 

sediments were deposited further down the valley. 

Three meander scars occur in this immediate area, and 

all have diameters of approximately 450 feet. The most 

northeastern of these scars contains the diatomite 

studied for this report; the sediments underlying the 

other downstream meander scars have not been examined. The Hixton deposit is the only diatomite that 

has been reported to dn,te from the Trempealeau Valley 

or from the entire Driftless Area. Other deposits 

probably occur in the Trempealeau Valley, and alm_ost 

certainly others must remain undiscovered in a regwn 

as large as the Driftless Area. 

STRATIGRAPHY 

The stratigraphic section from top to bottom, as examined near the center of semicircular meander scar, 

is as follows: 

Zone A is exposed at the surface and ranges from 6 to 

18 inches in thickness; peat and peaty soil, in part sandy, 

and abundant fragmental organic debris. 

Zone B consists of 6 to 8 inches of light- to bluish-gray 

friable diatomite, somewhat streaked and stained by 

iron oxide, containing abundant rootlets and fragmental 

organic debris. A half-inch layer of brownish-g:ay 

clay occurs between the diatomite and the overlymg 

peat. 

Zone 0 is about 6 inches of brownish-gray clay and 

organic matter. Partially decompose? piece~ ~f wood 

are common, and coarse, matted orgamc debns IS abundant. N oti.ceable odor of hydrogen sulfide. 

ZoneD consists of sand, fine to medium, whose thick· 

ness is undetermined, but the zone is in excess of 2 feet. 

Gray to black near the top, containing finely divided 
A6 CONTRIBUTIONS TO PALEONTOLOGY 

organic debris and large wood fragments. Grades to 

clean \vhite sand at depth. 

The modern surface of the area of the diatomite deposit is somewhat irregular and hummocky, typical of a 

boggy area. The present vegetation consists of a rank 

growth of grass and weeds and some small scattered 

brush; small trees are growing around the edge of the 

Arcadia Terrace escarpment. There is physiographic 

evidence for a former stream channel around the outer 

edge of the meander bend. This channel is about 6 to 

8 feet wide and 12 to 18 inches deep-comparable to the 

channel of the modern Trempealeau River in this part 

of the valley. The relation of this abandoned channel 

/ 

/-

/ 

/ 

/ 

to the diatomaceous and organic sediments is not clear. 

Perhaps it was eroded by a comparatively late stage 

of the Trempealeau River which reoccupied this area 

for a time. 

The postdiatomite peat accurnulation of zone A ranges 

from a, thin veneer of surface soil near the base of the 

Arcadia Terrace escarpment (in the channel mentioned 

above) to a thickness of about 18 inches in the direction 

of the main valley. This range suggests that the top of 

the underlying diatomite dips slightly toward the center of the meander scar, which seems to be a reasonable 

assumption. The organic matter of zone A contains 

abundant rootlets of comparatively modern origin. 

/ 

/ 

/ 

/ 

/ 

/ 

/ 

/ 

500 

_,..,---

/ 

N 

I 

0 500 FEET 

FIGURE 4.-'l'he Hixton d iatomite deposit and its relation to the older Areadia Terrace (stippled). 
LATE PLEISTOCENE DIATOMS, TREMPEALEAU VALLEY, WISCONSIN A7 

The Hixton diatomite of this report (zone B) is very 

consistent in thickness. Cores made in the abandoned 

channel at the outer edge of the meander plain show 

that here the diatomite is completely missing in some 

places and is only 2 to ± inches thick in others. Samples taken elsewhere have consistently shown a 6- to 

8-inch thickness. The diatomite is contaminated with 

rootlets and fragmental organic debris but is nearly free 

frmn clastic sediment. It shows irregular staining by 

iron oxide and excellent banding at some places. The 

diatomite contains no calcium carbonate, and there is 

no suggestion that the initial deposit was a marl. 

The lower organic layer (zone C) is composed of 

partly deeomposed wood fragments and matted organic 

debris. It is less completely oxidized than the peat of 

zone A, probably because it has been son1ewhat protected from circulating ground water by the relatively 

impervious overlying diatmnite. During sampling in 

Septmnber 1963, the water table was reached at a depth 

of about 3 feet. The diatomite of zone B and the organic 

! deposit of zone C must be virtually saturated at all 

I times, and the presence of hydrogen sulfide in zone C 

I indicates a reducing environment at present. In the 

1 area of the abandoned channel at the outer edge of the 

IIneander plain, zone C is missing, and the diatomite, 

I where present, rests directly on the sand of zone D. This 

ievidenee indicates that the deposit of organic material 

land diatomite (zones B and C) is indeed restricted to 

,the meander-plain reentrant and is not a pre-Arc-adia 

Terraee deposit exhumed by a later n1eanclering strean1. 

Zone D grades from a mixture of sand and organic 

:matter at the top to a clean white sand downward. 

Large frag1nents of wood, some exceeding a foot in 

jlength, were found in this zone. This wood is in a better 

!state of preservation than the fragments in overlying 

1

zone C, and immediately after excavation it did not a pI pear to be greatly different from modern waterlogged 

iwood buried under similar conditions. A sample of this 

:wood was submitted to R. A. Scott, U.S. Geological 

Survey, for identifieation. He reported "The coniferions wood is that of Picea. sp., spruee. It has been somelwhat degraded and eontains numbers of fungal hyphae." 

RADIOCARBON CHRONOLOGY 

Three samples of organic material associated with the 

Hixton diatmnite were submitted to the radiocarbon 

laboratory of the lT.S. Geological Survey for age determination. The youngest of these samples consisted of 

peat taken from the base of zone A of the stratigraphie 

:section at a depth of 16 to 18 inelms below the surfaee. 

;This sample was judged to be eontaminated by modern 

1

rootlets, and it was not dated. A sample of the partially 

!decomposed wood and matted organie debris of zone C, 

immediately underlying the di3!tomite (USGS Radioearbon Lab. No. W-1392), was dated at 10,990±600 

years B.P. A sample of spruce wood fron1 the upper 

part of zone D (USGS Radioearbon Lab. No. W -1391) 

was dated at 11,130±600 years B.P. These two dated 

samples indicate that no appreciable time elapsed between the deposition of the wood of zone D and the 

in1mediately overlying organic debris of zone C. I~t is 

unlikely that the wood sample (W-1391) has been contaminated by younger radioearbon. The elose correlation in radioearbon age between the wood sample and 

the sample of organic debris (W-1392) indicates that 

there has not been a ppreeiable eontaminrution of this 

sample. Both of the d3!tes, therefore, may be considered 

as valid within the limits of the dating technique, and 

no problem is posed by sample eontamination. 

The radiocarbon age of approximately 11,000 years 

B.P. for the organic material underlying the Hixton 

diatmnite suggests that this material was deposited 

during the Two Creeks Interstade of the Wiseonsin 

Glaeiation. Unfortunately, the peat overlying the 

diatomite could not be dated, for this would have provided incontrovertible evidenee for the upper ti1ne limit 

of diatomite deposition. The available evidenee, however, strongly suggests that no great amount of time 

elapsed between the deposition of organie debris of zone 

C and the overlying diatomite. This organic. debris 

is little oxidized, and the wood fragments, in paDticular. 

at the time of exc-avation had the appearance of freshly 

buried n1aterial. This excellent preservation of the organie matter indieates that it was buried rapidly by the 

deposition of the relatively impervious overlying diatomite and that stagnant reducing subaqueous eonditions 

were maintained throughout the deposition of both 

types of sediment. The ehange in deposition from organic debris to diatoms ean best be aeeounted for on the 

basis of a ehange in envirmunent. The Hixton diatomite was most probably laid down either during the 

latte-r part of the Two Creeks Interstade or during the 

following Valders Stade. 

DIATOM ASSEMBLAGE 

SAMPLE PREPARATION 

The samples were prepared for diatom study following standard laboratory proeedure, by dissoeiation in 

distilled water. Organic. matter was removed by heating in Clorox solution. A small amount of silt and 

fine sand was eliminated by decantation of the diatoms . . In suspensiOn. 

The size distribution of the diatoms in this deposit 

posed a speeial problem in sample preparation. The 

bulk of the sample was made up of Fragi7aria constl·uens var. 1Hnier, an elliptical diatom ranging from 
A8 CONTRIBUTIONS TO PALEONTOLOGY 

15 to less than 5 microns in length. Special techniques 

of preparation were necessitated by the great numbers 

of these relatively minute specimens. The settling rates 

of the small diatmns in this deposit were investigated 

by decantation of diatom suspensions in 150-milliliter 

beakers after periods of 40 minutes, 1, 2, 4, and 8 hours. 

Pouring after the 40-minute settling time removed 

nearly all the fine diatoms from the sample. Pouring 

after the 8-hour settling time still removed some of the 

very fine diaton1s. The other settling tin1es were internlediate in their effect. Because all the very fine diatoms 

in the sample were of one variety, removing most of 

the n1inute specimens from the sample by decantation 

in no way prejudiced the relative abundance of the other 

species and varieties. It was found advantageous to 

study samples from which the very abundant small 

diatoms had been cleaned. These samples allowed a 

more accurate estin1ate of the relative abundance of the 

larger species and varieties and were more suitable for 

photography. 

The prepared samples were mounted in Kollolith on 

strewn slides, and these were examined by traversing 

with a mechanical stage. Locations of individual specimens were recorded as coordinates of the mechanical 

st.a.ge. 

PALEOECOLOGIC INTBRPRETATION 

The frequency of occurrence of each species and 

variety of diatom observed in the Hixton diatomite is 

shown in table 1. Fragilaria constrruen.rs var. venter is 

listed as dominant because of its great relative abundance. The other forms are listed according to estimated relative frequency on a glass slide viewed at 250 

magnification, as follows: Abundant, at least one specimen in all fields of view; common, one specimen in many 

(but not all) fields of view; frequent, several specimens 

observed on slide, but seen only in a few fields of view ; 

rare~ one or two specimens on slide. The species and 

varieties identified in the deposit are recognized as forms 

living today, except for the two new species described 

herein. All these living species occur in fresh water, 

and only a few range into saline-water environments, 

which suggests that the Hixton diatmnite was almost 

certainly deposited in fresh water. 

The temperature ranges of the living species and 

varieties are indicated in table 1 as warm, temperate, 

or cool. The information available on maximun1 and 

minin11un temperature tolerance and opti1num range 

of growth for most fresh-water diaton1s is nearly all 

qualitative, and at best it is vague. The listing of 

"temperate" forms in table 1 may be somewhat Inisleading as it includes many forms that are indicated in 

the literature to be of common and widespread occurrence in the temperate zone of theN orthern Hemisphere. 

The limits of occurrence are not yet more closely defined, and these forms can be classified only on the broad 

spectrum of "temperate" environments. 

TABLE l.-Relative abundance, temperatnre, and pH range of 

diatoms from the Himton diatomite 

[Relative abundance: R, rare; F, frequent; C, common; A, abundant; D, dominant. Temperature: C, cool; T, temperate; W, warm] 

Relative Temper- abun- ature pH dance 

Melosira italica (Ehrenberg) Kiitzing _______________ C Cyclotella meneghiniana Kiitzing ____________________ R 

comta (Ehrenberg) Kiitzing_____________________ R Opephora martyi Heribaud __________________________ F Fragilaria capucina Desmazieres ____________________ R 

leptostauron (Ehrenberg) Hustedt_______________ F 

var. rhomboides Grunow __ ------------------ R construens var. venter (Ehrenberg) Grunow_____ D var. binodis (Ehrenberg) Grunow ___________ R var. subsalina Hustedt______________________ R Synedra ulna (Nitzsch) Ehrenberg__________________ C capitata Ehrenberg______________________________ R Meridion constrictum Ralfs__________________________ F 

Tabellariafenestrata (Lyngbye) Kiitzing ____________ R Eunotia bidentula W. Smith ________________________ R praerupta var. injlata Grunow __________________ R 

impressa Ehrenberg_____________________________ F 

lunaris (Ehrenberg) Grunow____________________ R gracilis (Ehrenberg) Rabenhorst________________ R 

monodon Ehrenberg ___ ------------------------- F formica Ehrenberg______________________________ R Cocconeis placentula Ehrenberg _____________________ R pediculus Ehrenberg ____________________________ R 

Diploneis ovalis var. oblongella (Naegeli) Cleve ______ R Stauroneis phoenicenteron (Nitzsch) Ehrenberg______ C Naricula cuspidata var. ambigua (Ehrenberg) Cleve_ F 

~~~~~~~~~:~ng~~~:~============================ ~ reinhardtii (Grunow) Grunow___________________ R dicephala (Ehrenberg) Kiitzing _________________ F oblonga (Kiitzing) Kiitzing ______________________ F amphibola Cleve ________________________________ R rotunda Andrews, n. sp _________________________ R 

Pinnularia interrupta W. Smith ____________________ R mesolepta var. anqusta Cleve____________________ R lata (Brebisson) W. Smith______________________ R borealis Ehrenberg ______________________________ R gibba (Ehrenberg) W. Smith ____________________ R 

cf. P. stomatophora (Grunow) Cleve ____________ R 

major (Kiitzing) W. Smith_-------------------- R esox Ehrenberg ___ ------------ __ ---------------- R viridis (Nitzsch) Ehrenberg _____________________ F 

streptoraphe Cleve ____________ --------------____ R Neidium bisulcatum (Lagerstedt) Cleve _____________ R iridis (Ehrenberg) Cleve ________________________ F var. vernalis Reichelt _______________________ R 

Caloneis silicula (Ehrenberg) Cleve _________________ F var. truncatula (Grunow) Cleve _____________ R trinodis (W. Smith) Boyer ______________________ F 

Gomphonema acuminatum Ehrenberg_______________ R 

var. coronata (Ehrenberg) W. Smith-------- R augur Ehrenberg ____ --------------------------- R '!nglf'statumy_r:-r .. undulata Grunow ______________ R tntncatum Kutzmg _____________________________ F qracile Ehrenberg _______________________________ R 

lanceolatum Ehrenberg__________________________ R constrictum Ehrenberg __________________________ F 

capitatum Ehrenberg ____ ----------------------- F Amphora ovalis (Kiitzing) Kiitzing__________________ F Cymbella ehrenbergii Kiitzing ________________________ C turgida Gregory_________________________________ R americana Schmidt _____________________________ F 

cistula (Hemprich) Grunow _____________________ R 

Epithemia zebra (Ehrenberg) Kiitzing_______________ R var. porcellus (Kiitzing) Grunow ___________ C turgida (Ehrenberg) Kiitzing____________________ A var. qranulata (Ehrenberg) Brun ___________ F irregularis Andrews, n. sp _______________________ F 

Rhopalodia gib/Ja (Ehrenberg) 0. Miiller _ ___________ F Hantzschia amphioxys (Ehrenberg) Grunow _________ F var. capitata Pantocsek _____________________ R 

Nitzschia thermalis (Ehrenberg) Grunow ___ ~--------- R Cymatopleura solea (Brebisson) W. Smith __________ R 

T 6. 0-9.0 T 

T 

T 7. 0-9.0 T 

T 6. 0-9.0 T 

T 7. 3-8.0 T 

T 

T 6. 0-11.0 T 

T 5. 0-9.5 T 

C-T 

C-T 

T 

C-T 7. 3-8.1 T 

T 

T 

T 

T 

T 

T 5. 0-9.0 T 8. 5-11.0 T 6. 5-9.0 T 6. &-9. 0 T 

T 6. 5-9.0 T 7. 0-9.0 T 6. 5-9.0 

---------- ----------

T 5. &-8. 0 T 

T 

C-T 4. 0-11.0 T 5. 9-7.0 C-T 7. 0-9.0 T 

c 

T 6. 9-7.6 c 5. 9-7.6 C-T 7.1-7. 5 T 5. 0-9.0 

7. 1 T 6. 0-9.5 

7. 0-7.6 T 

T 6. 5-9.0 T 

T 

T 

T 7.8 W-T 5. 5-9.0 W-T 

T 

T 6. 6 T 6. 0-9.0 T 

W-T 5. 5-9.0 

---------- ---------- T 6. 5-9.0 T 7. 0-9.0 T 6. 6 T 5. 5-9.5 

T 

---------- ----------

T 6. 0-11.0 T 6. 6 T 

T 

T 6. 0-9.5 

Of the 73 species and varieties recorded in the Hixton 

diatomite, 8 seem to favor a cool-water environment 

and 3, a warm-water environment. The fact that all 

these forms oecur only rarely is hardly conclusive evidence for paleotemperature, but it does suggest a relatively cool climate. Evidence is not sufficient to justify 
LATE PLEISTOCENE DIATOMS, TREMPEALEAU VALLEY, WISCONSIN A9 

attempting a comparison with the present climate of 

:west-central Wisconsin. 

The pH ranges of some of the diatoms occurring in 

the Hixton deposit are shown in table 1. These values 1

represent a synthesis of investigations by Sovereign 

(1958) on the diatoms of Crater Lake and by Patrick 

iand Freese ( 1961) on the diatoms of northern Alaska. 

!Many Hixton diatoms show a pH range in modern 

:waters from slightly acid to somewhat alkaline environjments. A vail able data indicate that the Hixton diatomite was deposited in a nearly neutral or perhaps 

1slightly alkaline environment. The relative rarity of 

lsuch acid-loving forms as E'l.lnot£a also suggests that the 

!environment of deposition was not markedly acidic. I 

! The ecology of Fragllaria construen8 var. venter is of 

!special importance, for this variety is by far the domirant constituent of the Hixton diatom assemblage. 

iHustedt (1931, p. 159) stated that the species F. con-

~tr1JJen8 is one of the commonest fresh-water diatoms, 

~found frequently in aU kinds of waters and especially 

iabundant in littoral, standing waters. Sovereign ( 1958, 

p. 107-108) reported that the type variety of the species 

is "widespread and abundant in the Pacific Northwest" 

~n waters ranging in pH from 6.0 to 9.0. He did not 

report var. venter from that area. Patrick and Freese 

1(1961, p. 148) indicated that var. ~venter is a widely distributed speeies, previously reported from the Arctic, 

~nd occurs commonly in their collections from northern 

Alaska. They give the following ecological data,: 

~'Fresh water. Lake plankton, scrapings from silt botltom of drained lake. pH, 7.3-8.0; temp, 12° C." 

I Although most of the diatoms of the Hixton deposit 

lhave a wide range of occurrence, many are reported to 

have affinities for shallow standing or flowing water. 

:The diatoms of the Hixton assemblage probably flour-

!ished in a small, shallow pond at the south edge of the 

!Trempealeau River flood plain. The depression conltaining this pond was formed by post-Cary erosion and 

!modified during alluviation of the valley which resulted 1

in the deposition of the Whitehall Terrace of Mankato 

lage farther downstream. The radiocarbon age of the 

:organic material underlying the diatomite suggests that 1

the diatomite was deposited during the latter part of 

:the Two Creeks Interstade or during the following 1

V alders Stade. The shallow pond was probably isollated from the main stream channel, and because of this 

!the pond received little clastic debris. A relatively high 1

\Vater table maintained a virtually constant water level. 

!A reducing environment of deposition for the diatomite 

!is indicated by the excellent preservation of the underllying organic matter. The diatomite and the underlying organic debris contain a noticeable trace of hydroigen sulfide, and the bluish tint of unoxidized parts of 

the diatomite suggests the presence of some ferrous iron 

compound. The composition of the diatom asse1nblage 

suggests that the pond waters were probably about neutral in pH during deposition of the diatomite. In summary, the site of deposition may be postulated as being 

a shallow fresh-water pond having stagnant reducing 

conditions prevalent in the 'bottom sediments. 

The change of environment that resulted in the deposition of the diatomite in contrast to the underlying and 

overlying organic debris is a problem of considerable 

interest. The organic matter underlying the diatomite 

includes large fragments of spruce wood and other debris in a relatively unoxidized condition. In contrast, 

the overlying organic debris consists largely of finely 

divided black peaty material showing a considerably 

greater degree of oxidation. Treatment of the underlying material with Clorox solution to oxidize the organic matter produced a rather violent reaction with 

rapid effervescence, whereas similar treatment of the 

overlying material produced a slow, mild reaction. 

The diatom content of both these organic deposits has 

been examined. In the underlying material, only three 

fonns of extremely rare occurrence have been identified : Tetracyclus rupestris, Pinnularia viridis var. su..-

detica.rt, and Epithernia turgida. The overlying organic deposit eontains a somewhat more varied but 

sparse assemblage of diatoms, as follows : 

Frayilaria sp. 

Eunotia robusta Ralfs 

praerupta Ehrenberg 

var. in/lata Grunow 

var. bidens (Ehrenberg) Grunow 

lapponica Grunow 

lunaris (Ehrenberg) Grunow 

.uracilis (Ehrenberg) Rabenhorst 

Navicula dicephala (Ehrenberg) Klitzing 

Pinnularia yibba var. linearis Hustedt 

viridis var. sudetica (Hilse) Hustedt 

sp. 

Gomphonetna intricaturn Kii.tziug 

Epithernia aruus (Ehrenberg) Klitzing 

zebra var. porcellus (Klitzing) Grunow 

H antzschia amphioa:ys var. capUata Pantocsek 

All these forms are of rare occurrence except for 

Eunotia robusta Ralfs, which is frequent. This assemblage is distinct from that of the Hixton diatomite, and 

it indicates deposition in a more acid, peat-bog environment. 

What then was the reason for the temporary eessation 

in the accumulation of plant debris at Hirton and the 

accumulation of the dia.tmnite? The occurrence of 

spruce prior to the diatomite deposition suggests a somewhat cooler climate than that which suppor,ts the 

modern oak-maple-pine forest of the region. Cooling 

of the climate related to the Valders Stade may have 
AlO CONTRIBUTIONS TO PALEONTOLOGY 

locally redueed the growth of vegetation, but allowed 

a relatively heavy bloom of diatoms in ~the pond. Temperature data on the oeeurrenee of modern diaton1s indieate that they may reproduee abundantly at temperatures too low to promote plant growth. For example, 

fresh-water diatoms have been reported growing in 

pools of melt water on ieebergs. A emnbination of lmv 

temperature during the Valders Stade and optimum 

loeal eonditions 1nay well aeeount for the diatomite 

aeeumulation at Hixton. 

SYSTEMAT'IC DESCRIPTIONS 

The classifieation of diatoms in this paper follows 

Moore ( 1954) through the rank of class. The reasons 

for the inclusion of the Diatomaceae in the kingdom 

Protista are ably presented by Moore ( 1954) , and 

Starrier ( 1959), and they need not be repeated here. 

The elassifieation of the rank of order follows Karsten 

( 1928). The elassifieation from the rank of suborder to 

that of subfamily follows that of Hendey (1937). This 

elassifieation does not differ greatly from that of Schlitt 

(1896) and Hustedt (1927-30, 1930, 1931-59), although 

there are smne trivial differenees in the sequenee of the 

genera. 

It seems desirable to state at this point some of the 

prineiples that have been followed in this paper with regard to infragenerie elassification. F'or most paleontologic studies it appears preferable< to adopt a binomial 

nomenelature over trinomial or quadrinomial systems. 

Renee, the new taxa described herein have been classified as species rather than varieties. The previously described varietal names have been retained, although the 

usefulness of this rank in paleontologic work on diatoms seems questionable. The rank of forrna, which has 

been used to a lesser extent by some authors, has been 

rejected for use in this paper. Those diatoms which 

have been previously classified in the fornw. have been 

raised or restored to either varietal or speeific rank. 

A synonymy is presented for eaeh species of diatom 

identified in the Hixton deposit. First, the description 

by the founder of the species is eited; second, references 

to the genus and species are given, as accepted in this 

paper, in chronologie order; third, synonyms and misidentifications are given, also in chronologie order. The 

most common errors, those of incorrect attributions of 

authorship, have been placed in the third category. 

Referenees which have not been examined by the writer 

are marked by an asterisk. Complete synonymies have 

not been given in this paper, for they may be found in 

one or more of the references cited. Ineluded in the 

synonymies are references to descriptions in the more 

important and more recent and readily available works 

such as Boyer (1927) and either Hustedt (1927-30, 

1931-59) or Hustedt (1930). To keep the length of this 

paper within reason, repetitive descriptions of previously described species and varieties have not been made. 

Complete descriptions can be obtained by consulting the 

various referenees given in the synonymies. Most of 

the species and varieties are illustrated in this paper, 

however, except for a few rare ones for which no 

adequate speci1nens were found. 

Information on the ecology and distribution of living 

fresh-water diatoms is sparse and is widely disseminated 

in the literature. Many of the earlier writers gave 

only sketchy data on the occurrence of the various 

speeies, and most of this information is nearly useless in 

determination of geographic and ecologic distribution. 

Fortunately, more attention is paid to these subjects 

by most current workers. The information presented 

in this paper on ecology and distribution is somewhat 

generalized from Hustedt (1927-30; 1931-59) and 

Hustedt (1930). Hustedt's reports deal with a basically 

temperate environment, namely that of central Europe. 

Certain of his environmental interpretations, for example, his mountain environments, are clearly not applicable to the Hixton deposit. On the other hand, the 

mountain species may be eonsidered to occur in cool or 

colder waters, and a reevaluation of Hustedt's interpretations has been made in considering the local 

conditions in Wisconsin. 

Kingdom PROTISTA 

Subkingdom PROTOCTISTA 

Phylum CHRYSOPHYTA 

Class DIATO:MACEAE 

Order CENTRALES 

Suborder DISCINEAE 

Family COS,CINODISCACEAE 

Subfamily MELOSIROIDEAE 

Genus MELOSIRA Agardh, 1824 

Melosira italica (Ehrenberg) Kiitzing 

Plate 1, figures 1-3 

Gallionella Ualica Ehrenberg, 1836 ?, Kgl. preuss. Akad. Wiss. 

Berlin, Ber., 1836, p. 53.* 

Melosira italioa (Ehrenberg) Kiitzing, 1844, Die kieselschaligen 

Bacillarien oder Diatomeen, p. 55, pl. 2, fig. 6. 

Hustedt, 1927, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 1, p. 257-262, fig. 109. 

Gallionella cren.u.lata Ehrenberg, 1843, Kgl. preuss. Akad. Wiss. 

Berlin, Phys. Abh., 1841, p. 376, pl. 2, fig. I, 41; pl. 3, fig. 

I, 28; pl. 4, fig. I, 31. 

Melosira crenu,lata (Ehrenberg) Kiitzing, 1844, Die kieselsehaligen Baeillarien oder Diatomeen, p. 55, pl. 2, fig. 8. 

Meloseira crenula.ta (Ehrenberg) Kiitzing. Boyer, 1927, Acad. 

Nat. Sci. Philadelphia Proc., v. 78, surpp., p. 29. 

111. italica is very eommon in the deposit and shows 

great variation in external shape. Valves range from 

short cylinders of relatively large diameter to elongate 

eylinders of relatively small diameter. Most specimens 

eonsist of two adjacent valves held together by the den-
LATE PLEISTOCENE DIATOMS, TREMPEALEAU VALLEY, WISCONSIN All 

ticulate margin; chains of frustules are rare. Hemi-

,spherical terminal valves are frequently found; frustules of two such valves occur more rarely. The rows of 

puncta are consistently fine and very slightly spiraled. 

The puncta vary slightly in size and are somewhat elon-

;gate longitudinally. The hemispherical terminal valves 

lare somewhat more coarsely punctate. 

M. italica is a common and widespread fresh-water 

!species, occurring in littoral and shallow-water environlments. 

. Diameters of figured specimens (USGS diatom cat. 

IN OS. 3260-207' 3260-271, 3260-270)' 22ft, lOp., 7 p.. 

Subfamily COSCINODISCOIDEAE 

Genus :CYCLOTELLA Kiitzing, 1834 

Cyclotella meneghiniana Kiitzing 

Plate 1, figure 4 

1

Cyclotella meneghiniana Kiitzing, 1844, Die kieselschaligen 

Bacillarien oder Diatomeen, p. 50, pl. 30, fig. 68. 

Boyer, 1927, Acad. Nat. Sci. Philadephia Proc., v. 78, supp., 

p.38. 

Hustedt, 1931, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 1, p. 341-344, fig.174. 

0. meneghiniana is a littoral and shallow-water form, 

!occurring predominantly in fresh water but ranging inIto brackish environments. It occurs very rarely in the 

deposit and is represented by small specimens. 

i Diameter of figured specimen (USGS diatom cat. 

IN o. 3261-55)' lOft. 

Cyclotella comta (Ehrenberg) Kiitzing 

I 

Plate 1, figure 5 

IDiscoplea comta Ehrenberg, 1844, Kgl. preuss. Akad. Wiss. 

I Berlin, Ber., 1842, p. 267. 

I

Cyclotella comta (Ehrenberg) Kiitzing, 1849, Species Algarum, 

p. 20. 

Boyer, 1927, Acad. Nat. Sci. PhiladelpMa Proc., v. 78, supp., 

p.40. 

Hustedt, 1928, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt 1, p. 354-356. 

, 0. comta is a common and widespread fresh-watel! 

'!pelagic form, occurring in lakes and rivers. It is rarely 

'found in this deposit. Specimens range from 16ft to 

138ft in diameter. 

i, Diameter of figured specimen (USGS diatom cat. 1

No. 3410-62), 38ft. 

Order PENN ALES 

Suborder ARAPHIDINEAE 

Family FRAGILARIACE.AE 

Subfamily FRAGILARIOIDEAE 

Genus OPEPHORA Petit, 1888 

Opephora martyi Heribaud 

Plate 1, figure 6 

Opephora martyi Heribaud, 1902, Diatomees fossiles d'Auvergne, 

p. 43-44, pl. 8, fig. 20. 

Boyer, 1927, Acad. Nat. Sci. Philadephia Proc., v. 78, supp., 

p.183. 

Hustedt, 1931, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 135, fig. 654. 

0. nwrtyi is commonly found in standing fresh 

waters, especially in eutrophic lakes. It is reported to 

occur frequently with species of Fragilaria. It is frequent in this deposit. Individuals range from 14ft to 

35ft in length. 

Length of figured specimen (USGS diatom cat. No. 

3410-61) '35ft. 

Genus FRAGILARIA Lyngbye, 1819 

Fragilaria capucina Desmazieres 

Fragilaria capucina Desmazieres. 1825, Plantes Cryptogames de 

la France, ed. 1, no. 453. * 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 78, supp., 

p.187. 

Hustedt, 1931, Die Kieselalgen Deutschlands, ()sterreichs, 

und der Schweiz, pt. 2, p. 144, fig. 659. 

F. capucina is a common fresh-water diatom in littoral 

environments and the plankton of fresh-water lakes. It 

is very rare in this deposit. Length about 32ft. 

Fragilaria leptostauron (Ehrenberg) Hustedt 

Plate 1, figure 7 

Biblarium leptostauron Ehrenberg, 1854, Mikrogeologie, pl. 1, 

fig. 35, 36. 

Fragilaria leptostauron (Ehrenberg) Hustedt, 1931, Die Kieselalgeo Deutschlands, Osterreichs, und der Schweiz, pt. 2, 

p. 153-155, fig. 668. 

Odontidium harrisonii W. Smith, 1856, Synopsis of the British 

Diatomaceae, v. 2, p. 18, pl. 60, fig. 373. 

Fragilaria harrisonii (W. Smith) Grunow, 1862, Kaiserl.-kgl. 

zool.-bot. Gesell. Wien, Verb., v. 12, p. 368. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 78, supp., 

p.189. 

F. leptostauron is a fresh-water species common in 

littoral and moist soil environments, as well as in standing w~ters. It occurs frequently in this deposit as 

specimens 15ft to 30ft long. 

Length of figured specimen (USGS diatom cat. No. 

3260-36) ' 16ft· 

Fragilaria leptostauron var. rhomboides Grunow 

Fragilaria harrisonii var. rhomboides Grunow, 1862, Kaiserl.-kgl. 

zool.-~bot. Gesell. Wien, Verb., v. 12, p. 368. 

Fragilaria leptostauron var. rhomboides Grunow. 

Hustedt, 1928, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 154, fig. 668 g. 

Occurrence of F. leptostauron var. rhornboides is 

similar to that of the type variety. This variety is very 

rare in this deposit. 
A12 CONTRIBUTIONS TO PALEONTOLOGY 

Fragilaria construens var. venter (Ehrenberg) Grunow 

Plate 1, figure 8 

Fragilaria venter· Ehrenberg, 1854, Mikrogeologie, pl. 8, fig. I, 

12; pl. II, fig. 14; pl. 13, fig. I, 4; pl. 14, fig. 50. 

Fragilaria canstruens var. venter (Ehrenberg) Grunow, in Van 

Heurck, 1881, Synopsis des diatomees de Belgique, p. 156, 

pl. 45, fig. 21B, 22, 23, 24B, 26A, B. 

Hustedt, 1931, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 158, fig. 670 h-m. 

F. constru1ens var. venter occurs by far most abundantly of any form in this deposit. The bulk of the deposit is made up of this one variety, which probably 

constitutes 80 to 90 percent of the total diatom content. 

This variety ranges in length from about 15~-t to 3~-t and 

perhaps even smaller. The type variety of this species 

has not been observed in this deposit, and two other related varieties occur only rarely. 

F. const1"'Uens is a very common and widespread freshwater form. It is especially abundant in littoral or 

shallow standing water. 

Length of figured specimen (USGS diatom cat. No. 

3410-63)' 13,u. 

Fragilaria construens var. binodis (Ehrenberg) Grunow 

Plate 1, figure 9 

Fragilaria binodis Ehrenberg, 1854, Mikrogeologie, pl. 5, fig. II, 

26. 

Fragilaria canstruens var. binadis (Ehrenberg) Grunow, 1862, 

Kaiserl.-kgl. zool.-bot. Gesell. Wien, Verb., v. 12, p. 371. 

Hustedt, 1931, DiE~ Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 158, fig. 670 d-g. 

Fr·agilaria canstruens binadis (Ehrenberg) Grunow. Boyer, 

1927, Acad. Nat. Sci. Philadelphia Proc., v. 78, supp., p. 

188. 

Occurrence of F. construens var. binodis is similar 

to that of F. con.struens var. venter. A rare fonn in 

this deposit. 

Length of figured specimen (lTSGS diatom cat. No. 

3261-24)' 16~-t. 

Fragilaria construens var. subsalina Hustedt 

Plate 1, figure 10 

Fragilaria canstruen8 var. subsalina Hustedt, 1925, Mitt. geogr. 

Gesell, und naturh. Mus. LUbeck, 2 Reihe, no. 30, p. 106, 

fig. 5-8.* 

Hustedt, 1931, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 159, fig. 670 p--s. 

F. construens var. sub8alina occurs in fresh water as 

'\vell as in shallow slightly brackish water. It is rare 

in this deposit. 

Length of figured specimen (lJSGS diatom cat. No. 

3410-3)' 35,u. 

Genus SYNEDRA Ehren berg, 1830 

Synedra ulna (Nitzsch) Ehrenberg 

Plate 1, figure 11 

Bacillaria ulna Nitzsch, 1817, Naturf. Gesell. Halle, Neue Schr. 

v. 3, p. 99.* 

Synedra ulna (Nitzsch) Ehrenberg, 1838, Die Infusionsthierchen 

als vollkommene Organismen, p. 211, pl. 17, fig. 1.* 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 78, supp., 

p.l98-199. 

Hustedt, 1932, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 195-201, fig. 691 A. 

8. ulna is a very common and wjdespread fresh-water 

diatom, occurring in greatest abundance in shallow, littoral waters of pools, ponds, and lakes. It occurs commonly as fragments in this deposit, but whole specimens 

are comparatively rare. 

Length of figured specimen (USGS diatom cat. No. 

3260-69)' 157ft· 

Synedra capitata Ehrenberg 

Plate 1, figure 12 

Synedra capitata Ehrenberg, 1836, Poggendorf Annalen Physik, 

pt. 3, fig. 3. * 

Boyer, 1927, Aead. Nat. Sci. Philadelphi·a Proc., v. 78, supp., 

p. 203-204. 

Hustedt, 1932, Die Kieselalgen Deutschlands, Osterre1chs, 

und der Schweiz, pt. 2, p. 201, fig. 692. 

S. cap,itata occurs generally in shallow, littoral standing water usually in association with S. ulna though less 

abundant than that species. Rare in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

3410--41)' 197ft· 

Subfamily MERIDIONOIDEAE 

Genus MERIDION Agardh, 1824 

Meridion constrictum Ralfs 

Plate 1, figure 13 

Meridian constrictum Ralfs, 1843, Annals and Mag. Nat. History, 

v. 12, p. 458-459, pl.18, fig. 2. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proe., v. 78, supp., 

p.173. 

Meridian (circulare var. ?) constrictum Ralfs. Van Heurck, 1881, 

Synopsis des diatomees de Belgique, pl. 51, fig. 14-15. 

Meridian circulare v•ar. canstricta (Ralfs) Van Heurck. Hustedt, 1931, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 9-3-94, fig. 627. 

JJJ. con8tricttnn has gradually drifted to the rank of a 

variety of 11/. circulare in much of the recent literature. 

Following Boyer ( 1927), it is here returned to specific 

rank as designated by the original author. Obviously a 

close relative of M. circulare, it is distinguished by a 

constriction near the apex. Jl,f. constrictum is commonly found in association with M. cir(J1.J)are, but only 

11!. constricturn was observed in this deposit. 

This species is of common fresh-water occurrence, 

particularly in flowing waters. It occurs frequently in 

this deposit as specimens 24~-t to 43~-t long. 

Length of figured specimen (USGS diatom cat. No. 

3260-170)' 39~-t. 
LATE PLEISTOCENE DIATOMS, TREMPEALEAU VALLEY, WISCONSIN A13 

Subfamily TABELLARIOIDEAE 

Genus TABELLARIA Ehrenberg, 1840 

Tabellaria fenestrata (Lyngbye) Kiitzing 

Plate 1, figure 14 

'])iatom.a fenestratum Lyngbye, 1819, Tentamen Hydrophyto~ 

logtae DaniHe, p. 180, pl. 61. * 

Tabellaria fenestrata (Lyngbye) Kiitzing, 1844, Die kieselsehaligen Bacillarien oder Diatomeen, p. 127, pl. 17, fig. 22; pl. 

30, fig. 73. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 78, supp., 

p.151-152. 

Hustedt, 1931, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 26-28, fig. 554. 

1 

T. fenestrata is a fresh-water species, which ranges 

!into slightly brackish environments. Common and 

!widespread in standing or gently flowing waters, esipecially in eutrophic lakes. Rare in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

i3410-25)' 72p.. 

Suborder RAPHIDlOIDINEAE 

Family EUNOTIACEAE 

Genus EUNOTIA Ehrenberg, 1837 

Eunotia bidentula W. Smith 

Plate 1, :figure 15 

1

Eunotia bidcntula W. Smith, 1856, Synopsis. of the British Diatomaceae, v. 2, p. 83. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 78, supp., 

p.223. 

Hustedt, 1932, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 277-278, fig. 744. 

i E. bidentula is a widely occurring fresh-water dialtom common in cool or cold waters. It occurs rarely 

l

in this deposit. Specimens are 50p. to 60ft long. 

. Length of figured specimen (USGS diatom cat. No. 

!3260-256)' 51p.. I 

Eunotia praerupta Ehrenberg var. in:fl.ata Grunow 

IEunotia. p·raerupta. var. inflata Grunow in Van Heurck, 1881, 

Synopsis des diatomees de Belgique, p. 143, pl. 34, fig. 17. 

Husteut, 1932, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 280, fig. 24 7 A, f-g. 

1 

E. praeru.pta var. inflata is a widespread fresh-water 

'diatom occurring commonly in marsh and spring en-

,vironments and more abundant in cooler waters. It 

I is rare in this deposit. 

Eunotia impressa Ehrenberg 

Plate 1, figure 16 

'Eunotia impressa Ehrenberg, 1854, Mikrogeologie, pl. 14, fig. 66; 

pl. 3, fig. IV, 20. 

'EunoUa pectinalis var. impressa (Ehrenberg) 0. Miiller, 1896, 

Forsch. Biol. Stat. PIOn, v. 6, p. 12. * 

Eunotia. pectinalis var. minor fo. irnpressa (Ehrenberg). Hustedt, in Paseher, 1930, Die Siisswasser-flora Mitteleuropas, 

no. 10, p. 182, fig. 239. 

Hustedt, 1932, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 298, fig. 763 g, h. 

E. impressa has been lowered in taxonomic rank to 

variety and finally to form. It occurs in ~this deposit 

frequently as a distinctive species, having none of the 

relatives imputed to it by quadrinomial nomenclature. 

It seems more reasonable to restore this form to the 

specific rank than to perpetuate an implied relationship 

to other taxa that cannot be conclusively demonstrated. 

E. impressa is a widespread and common species 

occurring in standing water and small streams. It is 

frequent in this deposit, and specimens are very constant 

in length-29ft to 32,u. 

Length of figured specimen (lTSGS diatom cat. No, 

3410-58)' 32ft. 

Eunotia lunaris (Ehrenberg) Grunow 

Plate 1, figure 17 

Synedra lunaris Ehrenberg, 1831. Kgl. preuss. Akad. Wiss. 

Berlin, Abh., p. 87. * 

Eunotia lunaris (Ehrenberg) Grunow, in Van Heurck, 1881, 

Synopsis des diatomees de Belgique, p. 144, pl. 35, fig. 3, 4, 

6A. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 78, supp., 

p. 225. 

Hustedt, 1932, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 302-304, fig. 769. 

E. lu;naris is widespread in cool, fresh-water environ~ 

ments, and is especially abundant in pools of bogs and 

marshes. It is rare in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

3410-65)' 125ft. 

Eunotia gracilis (Ehrenberg) Rabenhorst 

Plate 1, figure 18 

Himati.dium gracile Ehrenberg, 1843, Kgl. preuss. Akad. Wiss. 

Berlin, Phys. Abh., 1841, p. 417, pl. 2, fig. I, 9 ; pl. 3, fig. I, 41. 

Eunotia gracilis (Ehrenberg) Rabenhorst. Boyer, 1927, Acad. 

Nat. Sci. Philadelphia Proc., v. 78, supp., p. 217. 

Hustedt, 1932, Die Kieselalgen Deutsehlands, Osterreichs, 

und der Schweiz, pt. 2, p. 305, fig. 771. 

Eunotia gracilis Ehrenberg. Rabenhorst, 1864, Flora Europaea 

Algarum, p. 72. 

E. graciU.r.; is a common and widespread species of 

fresh-water diaton1. It is rare in this deposit. Speci. 

mens range in length from 63ft to 129ft. 

Length of figured specimen (lTSGS diatom cat. No. 

3260-222)' 63ft. 

Eunotia monodon Ehrenberg 

Plate 1, figures 19, 20 

EunoUa monodon Ehrenberg, 1854, Mikrogeologie, pl. 2, fig. II, 

26. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 78, supp. 

p. 221. 
A14 CONTRIBUTIONS TO PALEONTOLOGY 

Hustedrt, 1932, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 305-306, fig. 772 a, b. 

E. rrwnodon is a widespread and common fresh-water 

species, frequently occurring in springs, pools, and 

marshes. It is found frequently in this deposit. It 

shows a great variability in length, from 38p. to lOOp.. 

Length of figured specimens (USGS diatom cat. Nos. 

3260-229 and 3260-134) lOOp., 66p.. 

Eunotia formica Ehrenberg 

Plate 1, figure 21 

Eunotia formica Ehrenberg, 1843, Kgl. preuss. Akad. Wiss. 

Berlin, Phys. Abh., 1841, p. 414. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 78, supp. 

p.220. 

Hustedt, 1932, Die Kieselalgen Deutschlands, Osterreichs, 

und der Sehweiz, pt. 2, p. 308-310, fig. 775. 

E. form,ica is a widespread fresh-water species occurring in standing waters but seldom found in abundance. 

The species closely resembles E. monodon in this deposit, 

but it is found only rarely. 

Length of figured specimen (USGS diatom cat. No. 

3260-232)' 103p.. 

Suborder :MONORAPHIDINEAE 

Family ACHNANTHACEAE 

Subfamily COCCONE'IOIDEAE 

Genus COCCONEIS Ehrenberg, 1838 

'Cocconeis placentula Ehrenberg 

Plate 1, figure 22 

Oocooneis plooentula Ehrenberg, 1838, Die Infusionsthierchen 

als vollkommene Organismen, p. 194. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp. 

p. 244. 

Hustedt, 1933, Die Kieselalgen Deutschlands, Osterreiehs, 

und der Schweiz, pt. 2, p. 347-350, fig. 802 a, b. 

C. placentula is very common and widespread, occurring in most fresh-water environments. Rare in this 

deposit. 

Length of figured specimen (USGS diatom cat. No. 

3261-106)' 34p. 

Cocconeis pediculus Ehrenberg 

Plate 1, figure 23 

Oocconeis pediaulus Ehrenberg, 1838, Die Infusionsthierchen 

als vollkommene Organismen, p. 194, pl. 21, fig. 11. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p.244. 

Hustedt, 1933, Die Kieselalgen Deutschlands, Osterreichs, 

und der Sehweiz, pt. 2, p. 350-351, fig. 804. 

0. pediculus is a common and widespread fresh-water 

species which ranges into saline-water environments. 

It is rare in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

3260-25)' 25p. 

Suborder BIRAPHIDINEAE 

Family NA VICULACEAE 

Subfamily NAVICUL,OIDEAE 

Genus DIPLONEIS Ehrenberg, 1845 

Diploneis ovalis var. oblongella (Naegeli) Cleve 

Plate 1, figure 24 

Navicula oblongella Naegeli, in Kiitzing, 1849, Species Algarum, 

p. 890.* 

Diploneis ovalis var. oblongella (Naegeli) Cleve. Hustedt, 1937, 

Die Kieselalgen Deutschlands, Osterreichs, und der 

Schweiz, pt. 2, p. 672, fig. 1065 f-k. 

Diploneis ovalis var. oblongella Naegeli. Cleve, 1894, Kgl. svenska 

vetensk. akad. Hftlldl., v. 26, no. 2, p. 93. 

D. ovalis is a common and widespread species occurring in fresh- and slightly saline-water environments. 

It also occurs under subaerial conditions in marsh and 

moist soil environments. It is rare in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

3260-165)' 29p.. 

Genus STAURONEIS Ehrenberg, 1843 

Stauroneis phoenicenteron (Nitzsch) Ehrenberg 

Plate 1, figure 25 

Bacillaria phoenicenteron Nitzsch, 1817, Naturf. Gesell. HaUe 

Neue Schr., v. 3, pl. 3, fig. 12, 14.* 

Stauroneis phoenicenteron Ehrenberg, 1843, Kgl. preuss. Akad. 

Wiss. Berlin, Phys. Abh., 1841, pl. 2, fig. V, I. 

Stauroneis phoenicenteron (Nitzsch) Ehrenberg. Kiitzing, 

1844, Die kieselschaligen Bacillarien oder Diatomeen, p. 

104, pl. 3, fig. 53. 

Boyer, 1927, Acad. Nat. Sci. Philadelphi:a Proc., v. 79, supp., 

p. 421. 

Hustedt, 1959, Die Kieselalgen Deutschlands, Osterreichs, 

und der Schweiz, pt. 2, p. 766-770, fig.1118. 

S. phoenicenteron is very widespread and occurs commonly in littoral fresh-water environments that range 

from alkaline to slightly acid. It is common in this 

deposit and ranges from 69~-t to 173p in length. 

Length of figured specimen (USGS diatom cat. No. 

3260-156)' 116p.. 

Genus NAVICULA Bory, 1822 

Navicula cuspidata var. ambigua (Ehrenberg) Cleve 

Plate 2, figure 1 

Navicula ambigua Ehrenberg, 1843, Kgl. preuss. Akad. Wiss. 

Berlin, Phys. Abh., 1841, p. 417, pl. 2, fig. II, 9. 

Navicttla cuspidata var. ambigua (Ehrenberg) Cleve. Hustedt, 

1930, in Pascher, Die Siisswasser-flora Mitteleuropas, no. 

10, p. 268, fig. 434. 

Navicula cuspidata var. ambigua Ehrenberg. Cleve, 1894, Kgl. 

svenska vetensk. akad. Hand!., v. 26, no. 2, p. 110. 

Navicula ouspidata ambigua (Ehrenberg) Cleve. Boyer, 1927, 

Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., p. 366. 

N. ouspidata is a shallow-water, littoral species of 

widespread and common occurrence in fresh water. 
LATE PLEISTOCENE DIATOMS, TREMPEALEAU VALLEY, WISCONSIN A15 I 

The variety is frequently found in this deposit. It 

ranges in length from 95ft to 130ft. 

• Length of figured specimen (USGS diatom cat. No. 

~260-180),113ft. 

Navicula bacill um Ehren berg 

Plate 2, figure 2 

Navicula bacillum Ehrenberg, 1843, Kgl. preuss. Akad. Wiss. 

Berlin, Phys. Abh., 1841, p. 418, pl. 4, V, fig. 8. 

Cleve, 1894, Kgl. svenska vetensk. akad. Handl., v. 26, no. 2, 

p.137. 

Boyer, 1927, Acad. Nat. Sci. PhHadelphia Proc., v. 79, supp., 

p. 371-372. 

Hustedt, in Pascher, 1930, Die Siisswasser-:tlora Mitteleuropas,no.10,p.280-281,fig.465. 

! N. bacillum occurs frequently in the deposit, and it is 

hsually similar in appearance to the figured specimen. 

!The valves are not markedly elliptical, and the sides are 

~1early parallel. The forms in this deposit resemble var. 

rrregoryiana in shape, but the lateral margins are not 

p.oticeably concave. Specimens range from 40,p. to 55ft 

~n length. N. bacillum is a common and widespread 

f

resh-water species. 

Length of figured specimen (USGS diatom cat. No. 

410-30)' 51p.. 

1 

Navicula radiosa Kiitzing 

I Plate 2, figure 3 I 

Navicula rad·iosa Kiitzing, 1844, Die kieselschaligen Bacillarien 

oder Diatomeen, p. 91, pl. 4, fig. 23. 

Cleve, 1895, Kgl. svenska vetensk. akad. Handl., v. 27, no. 

3, p.17. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p.397. 

Hustedt, in Pascher, 1930, Die Siisswass·er-:tlora Mitteleuropas, no. 10, p. 299, fig. 513. 

, N. radio8a is a common fresh-water diatom of widekpread occurrence. It is rare in this deposit. 

I Length of figured specimen (USGS diatom cat. No. 

~261-136) ' 66JL. 

Navicula reinhardtii (Grunow) Grunow 

Plate 2, figure 4 

~tauroneis reinhardtii Grunow, 1860, Kaiserl.-kgl. zool.-bot. 

; Gesell. Wien, Verh., v. 10, p. 566. 

!Navicula remhardtii Grunow. Grunow, in Van Heurck, 1880, 

Synopsis des diatomees de Belgique, p. 86, pl. 7, fig. 5, 6. 

Cleve, 1895, Kgl. svenska veteusk. akad. Handl., v. 27, no. 

3,p.20. 

Hustedt, in Pascher, 1930, Die Siisswasser-:tlora Mitteleuropas,no.10,p.301,fig.519. 

'!]{avioula reinhardtii (Grunow) Van Heurck. Boyer, 1927 

! Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., p. 393. 

N. reinh(J;rdtii is a fresh-water diatom of widespread 

k>ccurrence that is seldom found in abundance. It is 

lrare in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

3260-188),45p. 

Navicula dicephala (Ehrenberg) Kiitzing 

Plate 2, figure 5 

Pinnularia dicephala Ehrenberg, 1838, Die Infusionsthierchen 

als vollkommene Organism en, p. 185. * 

Ehrenberg, 1843, Kgl. preuss. Akad. Wiss. Berlin, Phys. Abh., 

1841, pl. 2, fig. I, 29 ; pl. 2, fig. II, 5. 

Nat,icula dicephala (Ehrenberg) Kiitzing, 1844, Die Kieselschaligen Bacillarien oder Diatomeen, p. 96, pl. 28, fig. 60, 62. 

Navicu.la dicephala Klitzing. W. Smith, 1853, Synopsis of the 

British Diatomaceae, v. 1, p. 53, pl. 17, fig. 157. 

Navicu-la dicephala (Ehrenberg) W. Smith. Cleve, 1895, Kgl. 

svenska vetensk. akad. Handl., v. 27, no. 3, p. 21. 

Hustedt, in Pascher, 1930, Die Siisswasser-:tlora Mitteleuropas, no. 10, p. 302-303, fig. 526. 

Navicu.la dicephala W. Smith. Boyer, 1927, Acad. Nat. Sci. 

Philadelphia Proc., v. 79, supp., p. 386. 

N. dicephala is a widespread fresh-water diatom, not 

usually found in great abundance. It occurs frequently 

in this deposit. Specimens range in length from 25ft to 

42ft. 

Length of figured specimen (USGS diatom cat. No. 

3260-80)' 39ft. 

Navicula oblonga (Kiitzing) Kiitzing 

Plate 2, figure 6 

Fr1tstulia oblonga Kiitzing, Dec. 8, 1833, Algarum aquae dulcis 

Germaniae. * 

Navi.oula oblonga (Kiitzing) Kiitzing, 1844, Die kieselschaligen 

Bacillarien oder Diatomeen, p. 97, pl. 4, fig. 21. 

Navicula oblonga Klitzing. Cleve, 1895, Kgl. svenska vetensk. 

akad. Handl., v. 27, no. 3, p. 21. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p.395. 

Hustedt, in Pascher, 1930, Die Slisswasser-:tlora Mitteleuropas, no. 10, p. 307-308, fig. 550. 

N. oblonga is a widespread fresh-waterspecies of common occurrence, which is also found in slightly saline 

environments. It occurs frequently in this deposit. 

Its length ranges from 95ft to 140ft. 

Length of figured specimen (USGS diatom cat. No. 

3261-127)' 125ft. 

Navicula amphibola Cleve 

Plate 2, figure 7 

Navicula amphibola Cleve, 1891, Soc. pro Fauna et Flora Fennica, Acta, v. 8, no. 2, p. 33. 

Cleve, 1895, Kgl. svenska vetensk. akad. Handl., v. 27, no. 3, 

p. 45. 

Boyer, 1927, Acad. Nat. Sci. Philadel'Phia Proc., v. 79, supp., 

p. 405. 

Hustedt, in Pascher, 1930, Die Slisswasser-:tlora Mitteleuro:::ms, no 10, p. 309-310, fig. 554. 

It is difficult to ascertain the limits of variability intended by Cleve for N. ampkibola. Two distinctive, 

but apparently related, forms occur in this deposit. N. 
A16 CONTRIBUTIONS TO PALEONTOLOGY 

mnphibola has here been restricted to the more elongate 

form having distinctive rostrate or subcapitate produced ends. The other related form, more rotund and 

having b1unt subrostrate apices, is herein described as 

N. rotunda. N. a:tnphibola occurs rarely in this deposit. 

Specimens range in length from 65p. to 77 p.. It is a 

common and widespread fresh-water species. 

Length of figured specimen (lTSGS diatom eat. No. 

3260-116)' 73p.. 

Navicula rotunda Andrews, n. sp. 

Plate 2, figures 8, 9 

Valve of N. rotunda elliptical, rotund, length less than 

twice the width. Ends of valve subrostrate with blunt 

rounded apices. Axial area narrow, central area cruciform, extending laterally in the middle of the valve by 

shortening of the striae. Shorter striae at the middle 

of the valve irregular in length. Transverse striae 

composed of distinct puncta, slightly uneven in lineation and spacing. Striae 4.5-7 in 10~-t in the center, 

10 in lOp. near the apices. Puncta about 12 in lOp., more 

closely spaced nea.r the apices. Raphe has the appearance of a flattened slightly twisted thread having conspicuous central pores and hook-shaped polar terminals. 

Length 30~-t to 40~-t, width 20p. to 22/L. 

Holot.ype: lTSGS diatom cat. No. 3260-196 (fig. 8), 

length 40p.. Figured specimen : USGS diatom cat. No. 

3260-199 (fig. 9), length 32ft. lTSGS diatmnloc. 5016. 

This species shows strong affinity to N. amphibola 

Cleve, which is somewhat more frequent in the sample. 

It is distinguished from that species on the basis of its 

more rotund shape, more specifically, its high width to 

length ratio. The apices of N. rotunda are blunt, 

rounded, and subrostrate, whereas those of N. amphibola 

are markedly rostrate and considerably more produced. 

The absence of intermediate forms in the sample suggests that N. rot~tnda should be treated as a separate 

species rather than as a variant form of N. mnphibola. 

N. rotunda is rare in the deposit. 

Genus PINNULARIA Ehren berg 1840 

Pinnularia interrupta W. Smith 

Plate 2, figure 10 

Pinnularla interntpfa W. Smith, 1853. Synopsis of the British 

Diatomaceae, v. 1, p. 59, pl. 19, fig. 184. 

Cleve, 1895, Kgl. svenska vetensk. akad. Handl., v. 27, no. 3, 

p. 76. 

Boyer, 1927, Aead. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 434. 

Hustedt, in Pascher, 1930, Die Stisswasser-flora Mitteleuropas, no. 10, p. 317-318, fig. 573. 

P. interrupta is a common and widespread fresh-water 

species. It is rare in this deposit. Specimens are about 

80p.long. 

Length of figured specimen (USGS diatom cat. No. 

3260-4)' 78p.. 

Pinnularia mesolepta var. angusta Cleve 

Plate 2, figure 11 

Pinnularia mesolepta var. angusta Cleve, 1895, Kgl. svenska 

vetensk. akad. Handl., v. 27, no. 3, p. 76. 

Pinnularia mesolepta fo. angusta Cleve. Hustedt, in Pascher, 

1930, Die Si:isswasser-flora Mitteleuropas, no. 10, p. 319, 

fig. 575 b. 

P. mesolepta is a common fresh-water species of widespread occurrence in standing and flowing waters. It is 

rare in this deposit. Specimens range from 45p. to 58p. 

in length. 

Length of figured specimen (USGS diatom cat. No. 

3260-82)' 58p.. 

Pinnularia lata (Brebisson) W. Smith 

Plate 2, figure 12 

Frustulia lata Brebisson, 1838, Mem. Soc. Sci. Falaise, p. 18. * 

Pinnularia lata (Brebisson) W. Smith, 1853, Synopsis of the 

British Diatomaceae, v. 1, p. 55, pl. 18, fig. 167. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 437-438. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas,no.10,p.324-826,fig.595. 

Pinnularia lata Brebisson. Cleve, 1895, Kgl. svenska vetensk. 

akad. Handl., v. 27, no. 3, p. 81. 

P. lata is common in cool, fresh waters, occurring in 

streams and ponds. It is rare in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

3260-269), about 104;u. 

Pinnularia borealis Ehrenberg 

Plate 2, figure 13 

P'innularia borealis. Ehrenberg, 1843, Kgl. preuss. Akad. Wiss. 

Berlin, Phys. Abh., 1841, p. 420, pl. 1, fig. II, 6. 

Cleve, ::! 895, Kgl. svenska vetensk. akad. Handl., v. 27, no. 

3, p. 80-81. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p.437. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas,no.10,p.326,fig.597. 

P. borealis is a widespread fresh-water species, more 

common jn cool waters. It is rare in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

3410-10) '38p. 

Pinnularia gibba (Ehrenberg) W. Smith 

Plate 2, figure 14 

Stauroptem? gibba Ehrenberg, 1843, Kgl. preuss. Akad. Wiss. 

Berlin, Phys. Ahh., 1841, p. 423, pl. 1, fi,g, II, 3. 

Pinnularia gibba (Ehrenberg) W. Smith, 1853, Synopsis of the 

British Diatomaceae, v. 1, p. 58, pl. 19, fig. 180. 

Cleve, 1895, Kgl. svenska vetensk. akad. Handl., v. 27, no. 

3,p.82. 
LATE PLEISTOCENE DIATOMS, TREMPEALEAU VALLEY, WISCONSIN A17 

Pinnularia gibba (Van Heurck) Boyer, 1927, Acad. Nat. Sci. 

Philadelphia Proc., v. 79, supp., p. 440. 

Pinnnlaria gibba Ehrenberg. Hustedt, in Pascher, 1930, Die 

Siisswasser-fiora Mitteleuropas, no. 10, p. 327, fig. 600. 

P. glbba is a common and widespread fresh-water 

~pecies. It occurs rarely in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

3261-62)' 77 fL· 

Pinnularia cf. P. stomatophora (Grunow) Cleve 

Plate 2, figure 15 

Navicula stomatophora Grunow, in Schmidt, 1876, Atlas der 

Diatomaceen-Kunde, pl. 44, fig. 27-29. 

~,innularia st01n.atophora Grunow. Cleve, 1895, Kgl. svensJm 

vetensk. akad. Handl., v. 27, no. 3, p. 83. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 439. 

Hust~dt, in Pascher, 1930, Die Siisswasser-fiora Mitteleuro,_ 

pas,no.10,p.327-328,fig.605. 

, This form of P. stornatophora falls somewhat below 

tihe recognized size for the species but conforms in all 

<)ther respects. It occurs rarely in the deposit. P. stomatophora is found most commonly in cool fresh waters. 

! Length of figured specimen (USGS diatom cat. No. 

~260c.-.129) '48fL. 

Pinnularia major (Kutzing) W. Smith 

Plate 2, figure 16 

I 

Ji'rustulia major Kutzing, 1833, Synopsis Diatomearum, Linnaea v. 8, p. 547, fig. 25. 

Finnularia major (Klitzing) W. Smith, 1853, Synopsis of the 

British Diatomaceae, v.1, p. 54, pl. 18, fig. 162. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 446. 

"Jfavi,oola major (Kiitzing) Klitzing, 1844, Die kieselschaligen 

: Bacillarien oder Diatomeen, p. 97, pl. 4, fig. 19. 

~innularia major Kiitzing. Cleve, 1895, Kgl. svenska vetensk. 

akad, Handl., v. 27, no. 3, p. 89. 

. Pinnularia major (Klitzing) Cleve. Hustedt, in Pascher, 1930, 

Die Slisswasser-flora Mitteleuropas, no. 10, p. 331, fig. 614. 

i P. 1najor is a common and widespread fresh-water 

~pecies. It occurs rarely in this deposit. Specimens 

~ange from 200/L to 210/L in length. 

I Length of figured specimen (USGS diatom cat. No. 

$260-96) '200,u. I 

Pinnularia esox Ehrenberg 

Plate 2, figure 17 

Pinnularia esom Ehrenberg, 1843, Kgl. preuss. Akad. Wiss. Berlin, Phys. Abh., 1841, p. 420-421, pl. 1, fig. II, 4. 

Cleve, 1891, Soc. pro Fauna et Flora Fennica, Acta, v. 8, no. 

2, p. 24, pl. 1, fig. 3. 

Cleve, 189fi, Kgl. svenska vetensk. akad. Handl., v. 27, no. 

3, p. 90. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas,no.10,p.334,fig.616. 

Nat'icula, esow (Ehrenberg) Kiitzing, 1844, Die kieselschaUgen 

BacilLarien oder Diatomeen, p. 94, pl. 28, fig. 53. 

Pinnularia eww Cleve. Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., p. 444. 

The illustrations of P. esow in Ehrenberg ( 1843) and 

l{iitzing ( 1844) leave much to be desired, and they raise 

a legitimate question concerning the placing of this species in the genus Pinnularia. The written descriptions 

of these authors, however, seem to be applicable to the 

P. esom of Cleve ( 1891) and later authors. This species 

is now well recognized and established in the literature 

as Cleve (1891) described it, and there seems to be no 

need to reject P. esow Ehrenberg on the basis of the 

questionable original figure. 

P. esow is widespread in cool, fresh-water environments but rarely found elsewhere. It is rare in this 

deposit. 

Length of figured specimen (USGS diatom cat. No. 

3410-27)' 138fL. 

Pinnularia viridis (Nitzsch) Ehrenberg 

Plate 2, figure 18 

Bacillaria viridis Nitzsch, 1817, Beitrage zur Infusorienkunde 

oder Natu:r<beschreihung der Zerkarien und B>azHlarien, 

pl. 4, fig. 1-3. * 

Pi1-mula,ria viridis (Nitzsch) Ehrenberg. Boyer, 1927, Acad. Nat. 

Sci. Philadelphia Proc., v. 79, supp., p. 446-447. 

Hustedt, in Pascher, 1930, Die SUsswasser-flora Mitteleuropas,no.10,p.334-335,fig.617. 

Pinnularia viri.dis Nitzsch. Ehrenberg, 1838, Die Infusionsthierchen als vollkommene Organismen, p. 182. * 

Cleve, 1895, Kgl. svenska vetensk. akad. Handl., v. 27, no. 

3, p. 91-92. 

P. 'Viridi,s occurs frequently in this deposit. It shows 

considerable variation in size and shape, ranging in 

length from 68/L to 170/L. It is a common and widespread fresh-water species. 

Length of figured specimen (USGS diatom cat. No . 

3260-186)' 98/L. 

Pinn ularia streptoraphe Cleve 

Plate 2, figure 19 

Pinnula.ria streptoraphe Cleve, 1891, Soc. pro Fauna et Flora 

Fennica, Acta, v. 8, no. 2, p. 23. 

Cleve, 1895, Kgl. svenska vetensk. akad. Handl., v. 27, no. 3, 

p. 93. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p.448. 

Hustedt, in Pascher, 1930, Die Slisswasser-fiora Mitteleuropas,no.10,p.337,fig.620. 

P. streptoraphe is a fresh-water species of somewhat 

restricted occurrence in cool waters. The species occurs 

rarely in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

3260-263) ' 17 4/L. 
A1.8 CONTRIBUTIONS TO PALEONTOLOGY 

Genus NEIDIUM Pfitzer, 1871 

Neidium bisulcatum (Lagerstedt) Cleve 

Plate 2, :figure :20 

Navicula bisulcatunz. Lagerstedt, 1873, Kgl. svenska vetensk. 

akad. H:mdl., Bihang, v. 1, no. 14, p. 31, pl. 1, :fig. 8. 

Xcidium bi8ulcatum (Lagerstedt) Cleve. Boyer, 1927, Acad. 

Nat. Sci. Philadelphia Proc., v. 79, supp., p. 323. 

Hustedt, in Pascher, 1930, Die Siisswasser-:flora Mitteleuropas, no. 10, p. 242, :fig. 37 4. 

N eidium bi8ulcatum Lagerstedt. Cleve, 1894, Kgl. svenska 

vetensk. akad. Handl., v. 26, no. 2, p. 68. 

N. bisulcatum is a fresh-water species occurring 1n 

streams and ponds, more commonly in cool waters. It 

is rare in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

3261-88)' 43p.. 

Neidium iridis (Ehrenberg) Cleve 

Plate 2, figure 21 

N avioola iridis Ehrenberg, 1843, Kgl. preus·s. Akad. Wiss. Berlin, Phys. Abh., 1841, p. 418, pl. 4, fig. I, 2. 

Neidium iridis (Ehrenberg) Cleve. Boyer, 1927, Acad. Nat. Sci. 

Philadelphia Proc., v. 79, supp., p. 321. 

Hustedt, in Pascher, 1930, Die Siis~swasser-:flora Mitteleuropas,no.10,p.245,:fig.380. 

N eidium iridis Ehrenberg. Cleve, 1894, Kgl. svenska vetensk. 

akad. Handl., v. 26, no. 2, p. 69. 

N. iridis is a common fresh-water species of widespread occurrence. It is found frequently in this deposit. Specimens range in length from 69p. to 108p.. 

Length of figured specimen (USGS diatom cat. No. 

3261-82)' 80p. 

Neidium iridis var. vernalis Reichelt, n. comb. 

Plate 2, figure 22 

Netazum i·ddis fo. vernalis Reichelt, in Hustedt, in Pascher, 

1930, Die Siisswasser-:flora Mitteleuropas, no. 10, p. 245, 

:fig.380. 

N. iridi;; var. vernali8 occurs rarely in the deposit. 

Length of figured specimen (USGS diatom .. cat. No. 

3260-43)' 60~-t. 

Genus CALONEIS Cleve, 1894 

Caloneis silicula (Ehrenberg) Cleve 

Plate 3, figure 1 

Navicula 8ilicula Ehrenberg, 1843, Kgl. preuss. Akad. Wiss. 

Berlin, Phys. Abh., 1841, p. 419. 

Oalonei8 8ilicula (Ehrenberg) Cleve. Boyer. 1927, Aead. Nat. 

Sci. Philadelphia Proc., v. 79, supp., p. 308--309. 

Hustedt, in Pascher, 1930, Die Siisswasser-:flora Mitteleuropas, no. 10, p.236-239,fig. 362. 

Oaloneis 8ilicula Ehrenberg. Cleve, 1894, Kgl. svenska vetensk. 

akad. Handl. v. 26, no. 2, p. 51-52. 

0. siUC'Ula is a common and widespread fresh-water 

diatom. It occurs frequently in this deposit. Specimens range in length from 56p. to 73p.. 

Length of figured specin1en (USGS diatom cat. No. 

3260-206) ' 73p.. 

Caloneis silicula var. truncatula (Grunow) Cleve 

Plate 3, figure 2 

Navicula 8ilicula var. truncatula Grunow, in Van Heurck, 1880, 

Synopsis des diatomees de Belgique, pl. 12, fig. 25. 

Oaloneis silicula var. truncatula Grunow. Cleve, 1894, Kgl. 

svenska vetensk. akad. Handl., v. 26, no. 2, p. 52. 

Hustedt, in Pascher, 1930, Die Siisswasser-:flora Mitteleuropas, no. 10,p.238, fig. 363-364. 

0. silicu.Za var. truncatula is differentiated from the 

type by its more blunt ends and its straight or faintly 

triundulate lateral margins. It occurs rarely in this 

deposit. The specimens observed were about 40p. long. 

Length of figured specimen (USGS diatom cat. No. 

3410-57)' 43,u. 

Caloneis trinodis (W. Smith) Boyer 

Plate .3, figure 3 

N av·icula trinodis W. Smith, 1856, Synopsis of the British 

Diatomaceae, v. 2, p. 94. 

Lewis, 1862, Aead. Nat. Sci. Philadelphia Proc., v. 13, p. 66, 

pl. 2, fig. 6. 

Oalonei8 schumanniana var. trinodi8 Lewis. Cleve, 1894, Kgl. 

svenska vetensk. akad. Handl., v. 26, no. 2, p. 53. 

Oaloneis trinodis (Lewis) Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., p. 309-310. 

The assignment of the authorship of 0. trinodi8 to 

Lewis ( 1862) rather than W. Smith ( 1856) in many reports seems puzzling, for Lewis himself gave credit of 

authorship toW. Smith. 

0. trinodi8 is a common fresh-water species, often 

occurring in a8$ociation with 0. silieula. It is frequent 

in this deposit and ranges from 3lp. to 41p. in length. 

Length of figured specimen (USGS diatom cat. No. 

3260-166), 40J.t. 

Family GOMPHONEMACEAE 

Subfamily GOMPHONEMOIDEAE 

Genus GOMPHONE.MA Agardh, 1824 

Gomphonema acuminatum Ehrenberg 

Plate 3, figure 4 

Gomphonetna acuminatum Ehrenberg, 1831 ?, Kgl. preuss. Akad. 

Wiss. Berlin, Abh., 1831, p. 86. * 

Cleve, 1894, Kgl. svenska vetensk. akad. Handl., v. 26, no. 2, 

p. 184--185. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 290-291. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas, no. 10, p. 370-372, fig. 683. 

G. aC'U'rninatu1n is a very common fresh-water species 

of widespread distribution. It is rare in this deposit. 

Length of figured specimen (TJSGS diatom cat. No. 

3~60-47)' 40p.. 
LATE PLEISTOCENE DIATOMS, TREMPEALEAU VALLEY, WISCONSIN A19 

Gomphonema acuminatum var. coronata (Ehrenberg) W. Smith 

Plate 3, figure 5 

(Jomphonema coronatum Ehrenberg, 1840, Kgl. preuss. Akad. 

Wiss. Berlin, Ber., p. 211.* 

Gomphonema acuminatum var. coronata (Ehrenberg) W. Smith. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mittel1 europas,no.10,p.370,fig.684. 

Gomphonema acuminatum var. coronata Kiitzing. W. Smith, 

1853, Synopsis of the British Diatomaceae, v. 1, p. 79. 

Cfomphonema acuminatum fo. coronata Ehrenberg. Cleve, 1894, 

Kgl. svenska vetensk. akad. Handl., v. 26, no. 2, p. 184. 

qomphonema acuminatum coronatum (Ehrenberg) Boyer, 1927, 

Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., p. 291. 

G. acuminatum var. coronata is usually found in 

association with the type. It is rare in this deposit. 

Specimens range from 49,u to 59,u in length. 

Length of figured specimen (USGS diatom cat. No. 

q410-43)' 49,u. I 

Gomphonema augur Ehrenbe·rg 

Plate 3, figure 6 

~omphonema augur Ehrenberg, 1840, Kgl. preuss. Akad. Wiss. 

I Berlin, Ber., p. 211. * 

Cleve, 1894, Kgl. svenska vetensk. akad. Handl., v. 26, no 2, 

p.185. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p.293. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas, no. 10, p. 372, fig. 688. 

G. augur is of widespread occurrence in fresh waters 

but is not as common as G. amlminatum. It is rare in 

this deposit. 

! Length of figured specimen (USGS diatom cat. No. 

3ii10-56)' 42,u. 

I 

I Gomphonema angustatum var. undulata Grunow 

I Plate 3, figure 7 I 

(J,omphonema angustatum var. undulata Grunow, in Cleve, 1894, 

Kgl. svenska vetensk. akad. Handl., v. 26, no. 2, p. 181. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas,no.10,p.373,fig.694. 

i G. angutStatum var. undulata is a common and widespread fresh-water form. It is rare in this deposit. · 

I Length of figured specimen (USGS diatom cat. No. 

3F60-19), 46,u. 

· Gomphonema intricatum Kiitzing 

I Plate 3, figure 8 

Gjomphonema intricatum Kiitzing, 1844, Die Kieselschaligen 

' Bacillarien oder Diatomeen, p. 87, pl. 9, fig. 4. 

Cleve, 1894, Kgl. svenska vetensk. akad. Handl., v. 26, no. 2, 

p.181-182. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p.295. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas,no.10,p.375-376,fig.697. 

i G. intricatum is a widespread fresh-water species occfrring commonly in standing water. It is frequent jn 

tris deposit. It ranges in length from 30,u to 74,u. 

Length of figured specimen (USGS diatom cat. No. 

3260-26) ' 54,u. 

Gomphonema gracile Ehrenberg 

Plate 3, figure 9 

Gomphonema grac·ile Ehrenberg, 1838, Die Infusionsthierchen 

als vollkommene Organismen, p. 217, pL 18, fig. 3. * 

Cleve, 1894, Kgl. svenska vetensk. akad. Handl., v. 26, no. 

2, p. 182-183. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p.296. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropa.s, no. 10, p. 376, fig. 702. 

G. gracile is widespread in standing fresh water, more 

abundant in warm climates, but ranges commonly into 

temperate environments. It is rare in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

3260-121)' 60,u. 

Gomphonema 1anceolatum Ehrenberg 

Plate 3, figure 10 

Gomphonema lanceolatum Ehrenberg, 1843, Kgl. preuss. Akad. 

Wiss. Berlin, Phys. Abh., 1841, pl. 2, fig. I, 37. 

Kiitzing, 1844, Die kieselschaligen Bacillarien oder Diatomeen, p. 87, pl. 29, fig. 73; pl. 30, fig. 59. 

Grunow, in Van Heurck, 1880, Synopsis des diatomees de 

Belgique, pl. 24, fig. 11. 

Gomphonema gracile var. lanceolata Kiitzing. Cleve, 1894, Kgl. 

svenska vetensk. akad. Handl., v. 26, no. 2, p. 183. 

Gomphonema graci.le var. lanceolata (Kiitzing) Cleve. Hustedt, 

in Pascher, 1930, Die Siisswasser-flora Mitteleuropas, no. 

10,p.376,fig.703. 

Cleve (1894, p. 183) bases both his G.lanceolatum and 

his G. grac-ile var. lanceola.ta on G. lanceolatum Ehrenberg. Examination of the original description and 

figures of Ehrenberg ( 1843) clearly indicates, however, 

that G. lanceolatum Ehrenberg pertains only to forms 

designated by Cleve (1894) and later authors as G. 

gracile var.lanceolata. G.lanceolatum of Cleve (1894), 

Boyer (1927), Hustedt (1930), and others is a separate 

and distinct species. Cleve's name is invalid and should 

be replaced. 

The distribution of this species is similar to that of 

G. grac·ile. It occurs rarely in this deposit. 

Length of figured specimen (USGS diatom eat. No. 

3410-11)' 61,u. 

Gomphonema constrictum Ehrenberg 

Plate 3, figure 11 

Gornphonema constricturn Ehrenberg, 1830, Kgl. preuss. Akad. 

Wiss. Berlin, Abh., p. 63. * 

Grunow, in Van Heurck, 1880, Synopsis des diatomees de 

Belgique, p. 123, pl. 23, fig. 6. 

Cleve, 18~1. Kgl. svenska vetensk. akad. Handl., v. 2'6, no. 2, 

p.186. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 292-293. 
A20 CONTRIBUTIONS TO PALEONTOLOGY 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas, no. 10, p. 377, fig. 714. 

G. constrictum is widespread and common in freshwater environments. It is frequent in this deposit. 

Specimens range from 32p. to 56p. in length. 

Length of figured specimen (USGS diatom cat. No. 

8~60-100)' 49p.. 

Gomphonema capitatum Ehrenberg 

Plate 3, figure 12 

Gornphonema cacpitaturn Ehrenberg, 1838, Die Infusions,thierchen 

a1s vollkommene Organism en, pl. 18, fig. 2. * 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 292. 

Gornphonerna ( constricturn var. ?) capitatum Ehrenberg. Grunow, in Van Heurck, 1880, Synopsis des diatomees de 

Belgique, p. 123, pl. 23, fig. 7. 

Gornphonerna constricturn var. capi.tata Ehrenberg . Cleve, 1894, 

Kgl. svenska vetensk. akad. Handl., v. 26, no. 2, p. 186. 

Gomphonenw. con8tricturn var. capitata (Ehrenberg) Cleve. Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas,no. 10,p.377,fig.715. 

Although G. capitatwrn is considered by some to be a 

variety of G. constrictum1, there is a notable lack of resemblance between the two forms. G. constrictum shows 

a marked constriction near the rounded apex. G. capitatuJn has lateral margins only slightly convergent toward the broad, blunt apex. G. cap,itatwm is not all 

capitate; and although the name is inappropriate, it 

cannot be rejected for this reason. Following Boyer 

(1927), the for1n has been restored to specific rank, 

rather than retained as a variety of G. constricttun. 

G. capcitatum is a common and widespread fresh-water 

species. It occurs frequently in this deposit. Specimens 

range from 35~-t to 53~-t in length. 

Length of figured specimen (USGS diatom cat. No. 

3260-147)' 49~-t. 

Family CYM:BELLACEAE 

Subfamily CYMBELLOIDEAE 

Genus AMPHORA Ehrenberg, 1840 

Amphora ovalis (Kutzing) Kti.tzing 

Pia te 3, figure 13 

Frustulia, ovalis Ki.ttzing, 1833, Synopsis Diatomearum, Linnaea, 

v. 8, p. 539, fig. 5. 

A_rnphora ovalis Kii.tzing, 1844, Die kieselschaligen Bacillarien 

oder Diatomeen, p. 107, pl. 5, fig. 35, 39. 

Cleve, 1895, Kgl. svenska vetensk. akad. Handl., v. 27, no. 

3,p.104-105. • 

Boyer, 1927, Acacl. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 254. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas, no. 10, p. 342-343, fig. 628. 

A. ovalis is a common fresh-water diatom of widespread distribution. It occurs frequently in this deposit. 

Specimens range in length from 32,u to 48,u. 

Length of figured specimen (USGS diatom cat. No. 

3260-152)' 48p.. 

Genus CYM:BELLA Agardh, 1830 

Cymbella ehrenbergii Kutzing 

Plate 3, figure· 14 

Cyrnbella ehrenbergii Kiitzing, Die kieselschaligen Bacillarien 

oder Diatomeen, p. 79, pl. 6, fig. 11. 

Cleve, 1894, Kgl. svenska vetensk. akad. Handl., v. 26, no. 

2, p.165. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 275. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas, no. 10, p. 356, fig. 656. 

0. ehrenbergii is a common fresh-water diatom of 

widespread occurrenee. It is eommon in this deposit. 

It ranges in length from 100~-t to 153p.. 

Length of figured specimen (lTSGS diatom cat. No. 

3260-237)' 147~-t. 

Cymbella turgida Gregory 

Plate 3, figure 15 

Cyrnbella turgida Gregory, 1856, Quart. Jour. Micros. Sci., v. 4. 

p. 5, pl. 1, fig. 18. * 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 283-284. 

Cyrnbella (Encyonerna) turgida Gregory. Cleve, 1894, Kgl. 

svenska veten~k. aka d. Handl., v. 26, no. 2, p. 168. 

Cymbella t1trgida (Gregory) Cleve. Hustedt, in Pascher, 1930, 

Die Siisswasser-ftora Mitteleuropas, no. 10, p. 358. fig. 660. 

0. turgida is found most commonly in the tropics; it is 

also widespread in temperate fresh-water environments 

but occurs mostly as small individuals. It is rare in this 

deposit. 

Length of figured specimen (USGS diatom cat. No. 

3410-67)' 45p.. 

Cymbella americana Schmidt 

Plate 3, figures 16, 17 

Cyrnbella americana Schmidt, 1875, Atlas der DiatomaceenKunde, no. 3, pL 9, fig. 15, 20. 

Cymbella heteropteu1·a var. minor Cleve, 1894, Kgl. svenska 

vetensk. akad. Handl., v. 26, no. 2, p. 167. 

Hustedt, in Schmidt, 1931, Atlas der Diatomaceen-Kunde, 

no. 94. pl. 374, fig. 11, 12. 

0. a1nericana has elli p1 ical-lanceolate valve with 

markedly rostrate obtuse apices. Nearly bilaterally 

symmetrical with ventral margin slightly convex. 

Axial area narrow. Transverse striae slightly convergent, shortened at the center to form a transversely 

elliptical central area. Striae composed of distinct 

puncta, slightly uneven in lineation and spaoing. 

Striae 7-10 in 10~-t near the center, slightly closer at the 

ends. Puncta 17-18 in 10~-t, somewhak more closely 

spaced near the apices. :Raphe nearly straight, oblique 
LATE PLEISTOCENE DIATOMS, TREMPEALEAU VALLEY, WISCONSIN A21 

t,o the plane of the valve, and having conspicuous central 

pores deflected toward the ventral margin. Raphe terminates in small hyaline nodules at the polar extremities. 

Length 55,p. to 82~-t, width 20~-t to 23p.. 

Length of figured specimens (USGS diatom cat. Nos. 

3260-64 and 3261-86) 62p., 68,u. 

C. americana, as figured by Schmidt (1875, pl. 9), 

~ppears to be substantially identical with 0. heterople1l·ra var. minor as figured by Hustedt (1931, pl. 94). 

'!rhe apices of the specimens figured by Hustedt are 

perhaps a bit 1nore rostrate and attenuate, but the differ-

~nce is trivial. Cleve (1894, p. 167) states that C. amer-

~cana seems to be intermediate between 0. cuspidata and 

his C. heteropZeu'ra var. m-inor, and that the latter form 

differs from 0. cuspidata only in the somewhat different 

~hape of the ends and the more coarsely punctate striae. 

:J3oyer (1927, p. 275) considers 0. americana to be a 

tariety of 0. ehrenbergii. 

1 

0. mnericana and C. heteropleu,ra var. minor seem to I 

~e identical in all essential characteristics, and the name 

r. a·mericana is adopted for the speeies in this report 

~n the basis of its priority. Beeause a written diagnosis 

+f this species was not made by Sehmidt, and beeause 

Cleve's C. heteropleura var. minor was deseribed in a 

perfunctory manner, a definition of the species as it 

bccurs in the Hixton deposit is given above. 0. amerieana is smaller in size than C. heterople1tra and larger 

~n size than 0. navimdiformis and differs in the spacing 

d.f the transverse striae, but otherwise it resembles these 

~pecies in general appearance. A close affinity is ap- 1 

parent between (}. mnencana, 0. cusp·idata, 0. hetero-

};leura, and 0. nazn:mtliforrnis, but these species seem to 

~e distinctively different from 0. ehrenbergii. 0. 

(~mericana, is frequent in this deposit. 

Cymbella cistula (Hemprich) Grunow 

Plate 3, figure 18 

~acillaria cistula Hemprich, in Ehrenberg, 1828, Symbolae 

phy,sicae ( Phytozoa) , pl. 2, fig. IV, 10. * 

&ymbella cist·ula (Hemprich) Grunow, in Van Heurck, 1880, 

Synopsis des diRJtomees de Belgique, p. 64, pl. 2, fig. 12. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 280. 

Hustedt. in Pascher, 1930, Die Siisswasser-flora Mitteleuropas,no.10.p.363,fig.676a. 

¢tyrnbella cistttla Hemprich. Cleve. 1894, Kgl. svenska vetensk. 

akad. Handl., v. 26, no. 2, p. 173. 

C. cistula is a common fresh-water species of widespread distribution. It occurs rarely in this deposit. 

Length of figured specimen (USGS diatom cat. No. 

3410-27)' 78p.. 

Family EPITHEMIACEAE 

Subfamily EPITHEM:IOIDEAE 

Genus EPITHEMIA Brebisson, 1838 

Epithemia zebra (Ehrenberg) Kiitzing 

P1ate 3, figure 19 

N a.vicula zebra Ehrenberg, 1834, Kgl. preuss. Aka d. Wiss. 

Berlin, Abh., 1834, p. 118. * 

Epithemia zebra (Ehrenberg) KiHzing, 1844, Die kieselschaligen 

Bacillarien oder Diatomeen, p. 34, pl. 5, fig. 12. 

Boyer, 1927. Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p.490. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas, no. 10, p. 384-387, fig. 729. 

E. zebra is a widespread and common fresh-water 

diatom. It occurs rarely in this deposit. 

Lengt,h of figured specimen (USGS diatom cat. No. 

3261-146), 23p.. This individual is short, not entirely 

typical of the species. 

Epithemia zebra var. porcellus (Kiitzing) Grunow 

Plate 3, figure 20 

Epithemia porcellus Kii.tzing, 1844, Die kieselschaligen Bacillarien oder Diatomeen, p. 34, pl. 5, fig. 18, 19. 

Epithemia zebra var. porcellus (Kiitzing) Grunow, 1862, 

Kaiserl.-kgl. zool.-bot. Gesell. Wien, Verh., v. 12, p. 328. 

Hustedt, in Pascher, 1930, Die Sii.sswasser-flora Mitteleuropas, no. 10, p. 385, fig. 731. 

E. zebr·a var. porcellus is of common occurrence and of 

widespread distribution in fresh-water environments. 

It is common in this deposit, and it is relatively much 

more common than the type. Specimens observed 

range in length from 38p. to 76~-t. 

Length of figured specimen (USGS diatom cat. No. 

3260-35) ' 70p.. 

Epithemia turgida (Ehrenberg) Kiitzing 

Pia te 3, figure 21 

Navicula turgida Ehrenberg, 1830, Kgl. preuss. Aka d. Wiss. 

Berlin Abh., 1830, p. 64. * 

Epithemia turgida (Ehrenberg) Kii.t~ing, 1844, Die kieselschaligen Bacillarien oder Diatomeen, p. 34, pl. 5, fig. 14. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 488. 

Hustedt, in Pascher, 1930, Die Siisswasser-flora Mitteleuropas, no. 10, p. 387, fig. 733. 

E. turgida is of common and widespread occurrence 

in fresh and slightly brackish waters. It is abundant 

in this deposit. Specimens range in length from 32p. to 

127 p.. 

Length of figured specimen (lTSGS diatom cat. No. 

3260-17)' 12Qp.. 

Epithemia turgida var. granulata (Ehrenberg) Brun 

Eunotin granulata Ehrenberg, 1837 ?, Poggendorf Annalen 

Physik, 1836, p. 220, pl. 4, fig. 2. * 

Epi.them.ia turgida var. granulata (Ehrenberg) Brun, 1880, Diatomees des Alpes et du Jura, p. 44, pl. 2, fig. 13. 
A22 CONTRIBUTIONS TO PALEONTOLOGY 

Epithemia granulata (Ehrenberg) Kiitzing, 1844, Die kieselschaligen Bacillarien oder Diatomeen, p. 35-36, pl. 5, fig. 

20. 

Epithemia turgida granulata (Ehrenberg) Brun. Boyer, 1927, 

Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., p. 488-489. 

Epithernia turgida var. granulata (Ehrenberg) Grunow. Hustedt, in Pascher, 1930, Die Siisswasser-fiora Mitteleuropas, no.10, p. 387, fig. 734. 

The occurrence of E. turgida var. grar~J~J,lata is the 

same as that of the type. This variety is distinguished 

from the type by its more nearly parallel ventral and 

dorsal margins as well as its less capitate ends. It occurs frequently in this deposit, and it ranges in length 

from lOltt to 147ft· 

Epithemia irregularis Andrews, n. sp. 

Plate 3, figures 22-25 

Valves of E. irregularis arcuate, terminating in 

bluntly rounded or subcapitate ends. Ventral margin 

characterized by a broad moderately deep rounded 

emargination, usually occurring slightly off center, but 

less commonly in the center or, more rarely, near an end. 

Transverse costae radiate, alternating with two or three 

rows of puncta. Costae 4-5 in lO,u, striae 9-10 in 10~-t, 

puncta 8-9 in 10~-t. Length 43,u to 75,u; width 16~-t to 20p.. 

Holotype: USGS diatom cat. No. 3260-265 (fig. 22), 

length 49~-t. Paratypes: USGS diatom cat. Nos. 3410-8 

(fig. 23), length 75,u; 3410-44 (fig. 24), length 60~-t; 

3260-24 (fig. 25), length 50,u. USGS diatom loc. 5016. 

This species is similar in many respects to E. turgida, 

which also occurs in the deposit. The main difference 

is the presence of the ventral emargination of the valve. 

This emargination may occur anywhere along the ventral margin, although it is most common near the center 

of the valve. In some specimens the indentation seems 

to distort or twist the valve, but only parallel to the 

plane of the valve. The frequent occurrence of E. irregularis in an assemblage of normal individuals of 

many genera and species appears to eliminate the possibility of it being a tautological form of E. turgida. 

Genus RHOPALODIA 0. Muller, 1897 

Rhopalodia gibba (Ehrenberg) 0. Muller 

Plate 3, figure 26 

1v avwula gibba Ehrenberg, 1830, Kgl. preuss. Akad. Wiss. Berlin, Abh., 1830, p. 35, pl. 4, fig. 22. * 

Rhopalodia gibba (Ehrenberg) 0. Miiller, 1897, Bot. Jahrb., v. 

22, p. 65, pl. 1, fig. 15-17. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p.491. 

Hustedt, in Pascher, 1930, Die Siisswasser-fiora Mitteleuropas,no.10,p.390-391,fig.740. 

Eunotia gibba (Ehrenberg) Ehrenberg, 1843, Kgl. preuss. Akad. 

Wiss. Berlin, Phys. Abh., 1841, pl. 3, fig. I, 39. 

Epithemia gibba (Ehrenberg) Kiitzing, 1844, Die kieselschaligen 

Bacillarien oder Diatomeen, p. 35, pl. 4, fig. 22. 

R. gibba is a common fresh-water diatom of widespread occurrence. It is frequent in this deposit and 

shows great variation in length, ranging from 48p. to 

190p.. 

Length of figured specimen (USGS diatom cat. No. 

3260-101)' 58~-t. 

Family BACILLARIACEAE 

Subfamily NITZSCHIO·IDEAE 

Genus HANTZSCHIA Grunow, 1880 

Hantzschia amphioxys (Ehrenberg) Grunow 

Plate 3, figure 27 

Eunotia amphioxys Ehrenberg, 1843, Kgl. preuss. Akad. Wiss. 

Berlin, Phys. Abh., 1841, p. 413, pl. 1, fig. I, 26; pl. 2, fig. I, 

15; II, 16; pl. 3, fig. IV, 9; pl. 4, fig. V, 7. 

Hantzschia amphioxys (Ehrenberg) Grunow, in Cleve and 

Grunow, 1880, Kgl. svenska vetensk. akad. Handl., v. 17, 

no. 2, p. 103. 

Boyer, 1927, Acad. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 528. 

Hustedt, in Pascher, 1930, Die Siisswasser-fl:ora Mitteleuropas, no.10, p. 394-395, fig. 747. 

Nitzschia amphioaJys (Kiitzing) W. Smith, 1853, Synopsis of the 

British Diatomaceae, v. 1, p. 41, pl. 13, fig. 105. 

Hantzschia amphioxys var. major Grunow, in Van Heurck, 1881, 

Synopsis des diatomees de Belgique, 1885, p. 169, pl. 56, 

figs. 3, 11. 

Boyer, 1927, Aead. Nat. Sci. Philadelphia Proc., v. 79, supp., 

p. 529. 

Hustedt, in· Pascher, 1930, Die Siisswasser-fiora Mitteleuropas, no. 10, p. 394, fig. 749. 

H. ampkiowys has been revised in this report. to include H. amphiowys var. major Grunow. Study of this 

assemblage and of the pertinent literature suggests that 

var. major differs from the type only in size, and that 

the forms have been separated arbitrarily at the length 

of lOOp.. It seems more useful for one to treat these 

forms as a single taxon, recognizing a considerable 

variation in size and in coarseness of the transverse 

striations. 

H. amphlowys is of widespread occurrence, and it is 

found commonly in nearly all fresh-water environments. It is frequent in this deposit, and specimens 

range in length from 53~-t to 129p.. 

Length of figured specimen (USGS diatom cat. No. 

3260-107)' 72,u. 

Hantzschia amphioxys var. capitata Pantoesek 

Plate 3, figure 28 

H antzschia amphioxys var. capitata Pantocsek, 1901, Die 

Kieselalgen oder Bacillarien des Balaton, p. 83, pl. 9, fig. 

243. 

Hantzsohia amphioxys forma capitata 0. Muller. Hustedt, in 

Schmidt's, 1921, Atlas der Diatomaceen-Kunde, pl. 329, 

figs. 13, 14. 

Hustedt, in Pascher, 1930, Die Siisswasser-fiora Mitteleuropas,no.10,p.394,fig.748. 
LATE PLEISTOCENE DIATOMS, TREMPEALEAU VALLEY, WISCONSIN A23 

Hantzschia arnphioxys var. major fo. capitata Hustedt, in 

Schmidt's, 1921, Atlas der Diatomaceen-Kunde, pl. 329, 

fig. 3. 

Hustedt, in Pascher, 1930, Die Siisswasser-fl.ora Mitteleuropas, no. 10, p. 394. 

H. amphiowys var. cap-itata is here restored to the 

tank of variety. and it is considered to include the capitate individuals of II. arntphiowys in the broad sense in 

which that species is defined in this report. Although 

the original designation of var. capitata has been imputed to 0. Muller, reference has never been made to the 

{>ublication, and it has not been located. Authorship is 

here attributed to Pantocsek (1901), who established 

var. capitata as a new variety of the species. 

This variety is of widespread occurrence in freshWater environments and is often found in association 

ivith the type. It is rare in this deposit. 

Length of figured specimen (lTSGS diatom cat. No. 

~260-244)' 117,p. 

Genus NITZSCHIA Hassan, 1845 

Nitzschia thermalis (Ehrenberg) Grunow 

f'innularia thermalis Ehrenberg, 1841 ?, Kgl. preuss. Akad. 

I Wiss. Berlin, Ber., 1841, p. 21.* 

Ni.tz8chia therrnalis (Ehrenberg) Grunow, 1862, Kaiserl.-kgl. 

zool.-bot. Gesell. Wein, Verb., v. 12, p. 568-569, pl. 12, fig. 

22. 

S11trirella thermalis (Ehrenberg) Kiitzing, 1844, Die kieselschaligen Bacillarien oder Diatomeen, p. 60, pl. 3, fig. 46. 

]iritzschia thermalis Kiitzing. Hustedt, in Pascher, 1930, Die 

Siisswasser-fl.ora Mitteleuropas, no. 10, p. 403, 405, fig. 

771. 

: N. thermalis is a widespread fresh-water species of 

frequent occurrence. It is rare in this deposit. 

Suborder SURIRELLINEAE 

Family SURIRELLACEAE 

Subfamily SURIRELLOIDEAE 

Genus CY:MATOPLEURA W. Smith, 1851 

Cymatopleura solea (Brebisson) W. Smith 

$urirella .<wlea Brebisson, 1838, Considerations sur les dia1 tomees, p.17.* 

fJ(ymatoplettra solea (Brebisson) W. Smith. Boyer, 1927, Acad. 

Nat. Sci. Philadelphia Proc., v. 79, supp., p. 532. 

Hustedt, in Pascher, 1930, Die Siisswasser-fl.ora Mitteleuropas,no.10,p.425-426,fig.823a. 

f)ymatopleura solea (Kiitzing) W. Smith, 1851, Annals and 

I Mag. Nat. History, ser. 2, v. 7, p. 12-13, pl. 3, fig. 10-11. 

I 0. solea is a common fresh-water species having a 

widespread distribution. It is rare in this deposit. I 

REFERENCES CITED 

)?laek, R. F., 1959, Friends of tb(~ Pleistocene: Science, v. 130, 

p. 172-173. 

Boyer, C. S., 1927, SynopSJis of North American Diatomaceae: 

Acad. Nat. Sci. Philadelphia Proc., v. 78, supp., p. 1-228; 

v. 79, supp., p. 229-583. 

Chamberlin, T. C., and Salisbury, R. D., 1885, Preliminary paper 

on the Driftless Area of the Upper Mississippi Valley: U.S. 

Geol. Survey 6th Ann. Rept., p.199-322. 

Cleve, P. T., 1891, The diatoms of Finland: Soc. pro Fauna et 

Flora Fennica, Acta, v. 8, no. 2, 68 p., 2 pls. 

--- 1894, 1895, Synopsis of the naviculoid diatoms: Kgl. 

svenska vetensk. akad. Handl., v. 26, no. 2, 194 p., 5 pls., 1894; 

v. 27, no. 3, 219 p., 4 pls., 1895. 

Ehrenberg, C. G., 1843, Verbreitung und Einfl.uss des mikroskopischen Lebens in Siid- und Nord-Amerika: Kgl. preuss. 

Akad. Wiss. Berlin, Phys. Abh., 1841, p. 291-445,4 pls. 

Hendey, N. I., 1937, The plankton diatoms of the southern 

seas: Discovery Reports, v.16, p.151-364, pls. 6-13. 

Hole, F. D., 1943, Correlation of the glacial Border drift of north 

central Wisconsin: Am. Jour. Sci., v. 241, p. 498-516. 

Hustedt, Friedrich, 1927-30, 1931-59, Die Kieselalgen Deutschlands, Osterreichs, und der Schweiz, Band 7 of Rabenhorst, 

G. L., Kryptogamen-fl.ora * * *: Leipzig, Ak·ademiscbe 

Verlagsgesellschaft, pt. 1, 920 p., 1927-30; pt. 2, 845 p., 

1931-59. 

Hustedt, Friedrich, 1930, Bacillariophyta (Diatomeae), Heft 10 

of Pascher, Adolf, ed., Die SUsswasser-:tlora Mitteleuropas: 

Jena, Gustav Fischer, 466 p. 

Karsten, George, 1928, Bacillariopbyta (Diatomeae) in Engler, 

Adolf, Die natiirlicben Pfl.anzenfamilien. Band 2, Peridineae (Dinofl.agellatae), Diatomeae (Bacillariopbyta), 

Myxomycetes : Leipzig, Wilhelm Engelmann, p. 105-303. 

Kiitzing, F. T., 1844, Die kieselschaligen Bacillarien oder Diatomeen: N ordhausen, 152 p., 30 pls. 

Lewis, F. W., 1862, Notes on new and rarer species of Diatomaceae of the United States sea board: Acad. Nat. Sci. 

Philadelphia Proc., v. 13, p. 61-71, pls. 1-·2. 

Moore, R. C., 1954, Kingdom of organisms named Protista : Jour. 

Paleontology, v. 28, p. 588-598. 

Pantocsek, Josef, 1901, Die Kieselalgen oder Bacillarien des 

Balaton : Resultate der wissenschaftliche Erforscbung des 

Balatonsees, v. 2, sec. 2, 112 p., 15 pls. 

Patrick, Ruth, and Freese, L. R., 1961, Diatoms (Bacillariopbyceae) from northern Alaska: Acad. Nat. Sci. Philadelphia Proc., v. 112, p. 129-293, 4 pls. 

Schmidt, Adolf, 1875, Atlas der Diatomaceen-Kunde, Heft 3: 

Leipzig, 0. R. Reisland, pls. 9-12. 

Schutt, Franz, 1896, Bacillariales, in Engler, Adolf, and Prantl, 

K. A. E., Die natiirlichen Pfl.anzenfamilien : Leipzig, pt. 1, 

Abt.lb, p. 31-153. 

Smith, William, 1853, 1856, A synopsis of the British Diatomaceae: London, v. 1, 89 p., pls. 1-31, 1853; v. 2, 104 p., pls. 

32-52, A-E, 1856. 

Sovereign, H. E., 1958, The diatoms of Crater Lake, Oregon : Am. 

Micros. Soc. Trans., v. 77, no. 2, p. 96-134,4 pls. 

Stanier, R. Y., 1959, Introduction to the Protista, in Edmonson, 

w. T., Fresh-water biology, 2d ed.: New York, John Wiley 

and Sons, p. 7-15. 

Van Heurck, Henri, 1880-85, Synopsis des diatomees de Belgique: 

Anvers, 235 p., pls. 1-132, A-C. 

Weidman, Samuel, 1907, The geology of north central Wisconsin: Wisconsin Geol. and Nat. History Survey, v. 16, 697 p. 

INDEX 

[Italic page numbers indicate major references and descriptions] 

A 

Page 

Aichnanthaceae________ ____ ___________ ____ ____ A14 

Aicknowledgments ___________________________ _ 

a4uminatum coronata, Gomphonema __ __ 8, 18, 19, pl. 3 

j Gomphonema ____________ __________ 8, 18, 19, pl. 3 

Age determination of deposits, paleoecologicaL 1 

radiocarbon ____________________________ 1, 2, 7, 9 

Ajge of deposits _______________________________ 2, 3, 4 

a1[ibigua, Navicula____________________________ 11;. 

' Navicula conspidata ___________________ 8, 11;., pl. 2 

at,nericana, Cymbella ___________________ 8, 20, 21, pl. 3 

amphibola, Navicula ___________________ 8, 15, 16, pl. 2 

a1:(!phio.rys capitata, Hantzschia _______ 8, 9, 22, 23, pl. 3 

E·unotia_ _____________ _ ________________ 22 

Hantzschia_ ----------------------- 8, 22, 23, pl. 3 

major capitata, Hantzschia_ _______________ 23 

Hantzschia_____________ ___ ____________ 22 

Nitzschia_________________________________ 22 

A,mphora_ ____________________ ___ __________ ___ 20 

1 ovalis _________________________________ 8, 20, pl. 3 

ai(gusta, Pinnularia mesolepta ____________ 8,16,pl. 2 

a·~gustatum undulata, Gomphonema _______ 8, 19,pl. 3 

~;:~~::*:;;;~~~~~~ ~ ~~ ~ ~~~ ~ ~~ ~ ~~~ ~ ~~~ ~ ~~ ~ ~ ~~ ~ 4, 5~~ ai:gus, Epithemia______________________________ 9 

aftgur, Gomphonema _____________________ 8, 19, pl. 3 

B 

~acillaria cistula __________ _ 21 

i phoenicenteron____________________________ 11;. 

ulna______________________________________ 12 

viridis_____ _ _ ___ _ _ __ _ __ _ ___ _ __ _ __ _ _ __ _ __ _ _ _ 17 

~acillariaceae______________ _____________ ______ 22 

bfcillum.gregoryiana, Navicula________________ 15 

~ibl:,~~~u::;;~;;;l~;~~~~ ~ ~~ ~ ~ ~~ ~ ~~~~~~~~ ~- ~~: :· p\ ~ bidens, E·unotia praerupta__ _ _ _ _ ___ _ ___ _ _ _ ____ _ 9 

btdentula, Eunotia _______________________ 8, 13, pl. 1 

bl'nodis, Fragilaria_____________________________ 12 

Fragilaria construens _________________ 8, 12, pl. 1 

~iraphidineae_ _ _ __ _ __ _ _ __ _ __ _ _ __ _ _ _ _ _ __ _ ___ _ _ 14 

~::~:i~7f:~:a····················· ~ 17, 18, p/: bprealis, Pinnularia _______________________ 8, 16, pl. 2 

~oyer, C. S., cited____________________________ 10 

! 

! c 

(faloneis _ ___________ _ __ __ ____ ___ _ ___ _________ 18 

! schumanniana trinodis _ _ __ _________________ 18 

siliwla_ --------------- ______________ 8, 18, pl. 3 

truncatula __ ______________________ 8, 18, pl. 3 

1 

trinodis _______________________________ 8,18,pl. 3 

*pitata, Gomphonema constrictum_ _ _ _______ __ 20 

Hantzschia amphiorys ___________ 8, 9, 22, 23, pl. 3 

amphiorys major______________________ 23 

Synedra ________________________________ 12,pl. 1 

CfPifat·um, Gomphonema __________________ 8,20, pl. 3 

, Gomphonema constrictum_________________ 20 

c~pucina, Fragilaria________________ _______ ____ 8,11 

tary glacier _________________________________ _ 

cpary outwash ____________ _ 

¢entral Lowland physiog-ra;~~~-;;~~~~~~~~~~~ Cfentrales___ ____________________ ____________ 10 

Page 

Chamberlin, T. C., quoted___________________ A1 

Chert ________________________________________ _ 

Chippewa lobe __ ----------------------------- Chrysophyta_________________________________ 10 

circulare, 1\.Ieridion_____ _________ _ ___ __________ 12 

constrict a, 1\,feridion___ _ __ __ _ _ _ _ _ __ _ __ _ ____ 12 

cistula, Bacilluria_____________________________ 21 

Cymbella ------------------- __________ 8, 21, pl. 3 

Clay ____ ------------------------ ______ _ _ _____ 5 

Cocconeis __ _ ___________ _______ _____ _ ___ ___ ____ 11;. 

Cocconeis pediculus _______________________ 8, 11;., pl. 1 

placentula ---------------------------- 8, 11;., pl. 1 

comta, Cyclotella -------------------------- 8.11, pl. 1 Discoplea ____ __ ________ _ ___ _ _ __ _ ______ _ __ _ 11 

constricta, 1\.Ieridion circulare ------------------ 12 

constrictum capitata, Gomphonema _ _ __________ 20 

capitatum, Gomphonema ------------------ 20 

Gomphonema ---------------------- 8, 19, 20, pl. 3 

~Meridian----------------------------- 8,12, pl. 1 

construens binodis, Fragilaria _____________ 8,12, pl. 1 

Fragilaria_________ _ __ _______ ____ ______ _ __ _ 12 

subsalina, Fragilaria __________________ 8,12, pl. 1 

venter, Fragilaria __ ---------------- 7. 8, 9,12, pl.1 

coronata, Gomphonema acuminatum ____ 8, 18, 19, pl. 3 

coronatum, Gomphonema______________________ 19 

Cortland School District_____________________ 3 

Cortland Terrace_____________________________ 3, 4 

Coscinodiscaceae __ ------------------ _________ 10, 11 

crenulata, Gallionella__________________________ 10 

Meloseira ___ _ _ ___ __________ ___ _______ __ __ _ 10 

Melosira---------------------------------- 10 

cuspidata ambigua, Navicula ______________ 8, 11;., pl. 2 

Navicula-------------·--------------------- 14 

Cymbella --------------------------------- 21 

Cyclotella __________________ --------- _ ___ _ __ _ __ 10 

comta -------------------------------- 8, 11, pl. 1 

meneghiniana -----------------------· 8, 11, pl. 1 

Cymatoplt;ura _ --------------- ____ ------------ 23 

solea ------------------------ ------------ 8, 23 

Cymbella __ -----· --------------- ------------ ~0 

americana------------------------ 8, 20, 21, pl. 3 

cistnla_ ---------------- ______________ 8, 21, pl. 3 

cuspidata _____________________ . _ __ _ ___ _ __ _ 21 

ehrenbergii__ ______________________ 8, 20, 21, pl. 3 

heteropleura --------------- -----~---------- 21 

minor--------------------------------- 20.21 

naviculiformis ----------------------------- 21 

turgida _________ --------------------- 8, 20, pl. 3 

(Encyonema) turgida______________________ 20 

Cymbellaceae _ _ _ _______________ _ ___ _ _________ 20 

Cymbelloideae _ _ _ ___________ _____ ______ ______ 20 

D 

Denny, Charles S., cited ________________ _ 

Diatnma fenestratu-m__________________________ 13 

Diatomaceae _ -------------------------------- 10 

Diatomite_---------------------------- 1, 3, 4, 6, 7,10 

Diatoms.------------------------------------- 8 

Diatoms, ecology_____________________________ 10 

frr,quency of occurrence___________________ 8 

pH ranges ____ ------------- ______________ _ 

temperature ranges_______________________ 8,10 

Page 

dicephala, Navicula __ -----------------__ AS, 15, pl. 2 

Pinnularia __ ------------------ _____ __ __ __ 15 

Diploneis________ __ _____ _ __ _ __ ___ ___ ____ ___ __ 11;. 

oval is __ --_________________________________ 11;. 

oblongella ________________________ 8, 11;., pl. 1 

Discineae__ __ ____ __ __ ____ _ ___ _ _____ _____ __ ___ _ 10 

Discoplea comta __________________ ------------ 11 

Dolomite ______________________ ---- ________ --_ 2 

Drainage_------------------------------------

Driftless Area ________________________________ 1, 2, 5 

E 

ehrenbergii, Cymbella __ ---------------- 8, 20, 21, pl. 3 

(Encyonema) turgida, Cymbella_______________ 20 

Eptthemia __________________ --------------- _ _ _ 21 

argus ____________________________________ _ 

gibba ____________________________ ------.- 22 

gran.ulata __ ---------------------- _________ 21, 22 

irregularis _________ ----------------- 8, 2~, pl. 3 

porcellus ____ _____________ ------- _ _ _ __ _ _ _ __ 21 

turgida _____________________________ 8,9,21,pl. 3 

granulata ___________________________ 8, 21, 22 

zebra _________________________________ 8, 21, pl. 3 

porcellus _______________________ 8, 9, 21, pl. 3 

Epithemiaceae _______________________ ------- 21 

Epithemioideae ____ -------------------- ·----- 21 

Erosion _____ --------------------------------- 2, 5 

esox, Navicula _______________________ ·--------- 17 

Pinn-ularia ___________________ -------- 8, 17, pl. 2 

Eunotia _ _ _ _ _ _ __ ______ __ __ ____ ____ ___ __ _ _ ____ _ 9, 13 

amphioxys_ ___ ____ ---~--------------- ____ 22 

bidentula _____________________________ 8, 13, pl. 1 

formica _______________________________ 8,14, pl. 1 

gibba ______________________________ ·------- 22 

gracilis _______________________________ 8, 13, pl. 1 

granulata ___________________ ------------- 21,22 

impressa ______________________________ 8, 13, pl. 1 

lappnnica ____ __________ ------ __________ --- 9 

lunaris ___ ________________________ -- 8, 9, 13, pl. 1 

monodon ___ -------------- ___________ 8, 13, pl. 1 

pectinalis impressa________________________ 13 

minor impressa_______________________ 13 

praerupta __________________ --------------- 9,13 

bidens _ _ _ _ ___ __ ___ __ _ _ __ _ ____ __ _ __ ____ 9 

in/lata ____ -------------------------- 8, 9,13 

robusta _______________ -----· _______ -- __ _ _ _ 9 

Eunotiaceae ____ --------- _______ _ _ ___ ___ _ _ _ __ _ 13 

F 

jenestrata, Tabetlaria __________ -------- ____ 8, 13, pl.1 

jenestratum, Diatcma ___ ---------------- _ _ _____ 13 

Fieldwork, summary __ -- ____________ ----_----

forma _________ ------------------------------- 10 formica, Eunotia __________________________ ~. 11;., pl. 1 

Fragilaria ______________________________ -- __ --- 11 

binodis ___________________________ ------- 12 

capucina ______________________ ----- __ __ __ _ 8, 11 

constmens ______ . ________________ - _- _ __ _ __ 12 

binodis ________ ·----------------- 8,12, pl. 1 

subsalina _________________________ 8,12, pl. 1 

renter ___________ -----· ______ 7,8, 9, 12, pl.1 

lwrrisonii -------------------------------- 11 

leptostauron __________ ___ ----------- 8,11,pl.1 

rhomboides ____________________________ 8,11 

venter_____________________________________ 12 

sp ___________ _ 9 

A25 
A26 

Fragilarioideae_ 

Freese, L. R., cited __________________________ _ 

Fru.~tulia lata ____________ --------------------

major _____________ ----------- ___ ---- _____ _ oblonga __________________________________ _ 

ova lis 

G 

Gallionella crenulata _______ _ 

Page 

All 

9 

16 

17 

15 

20 

10 

italica___ __ __ _____ _ _ _ _ ______ _ _ _ _ __ _ _ __ __ _ _ _ 10 

Geologic history, Quaternary_________________ 4 

Geology of region _______________ -------------- 2 

gibba, Epithemia______________________________ 22 

Eunotia ___ ------------------------------- 22 

linearis, Pinnularia_______________________ 9 

Navicula__________________________________ 22 

Pinnularia ______________________ __ 16. 17, pl 2 

Rhopalodia _________________________ 8, 22, pl. 3 

Stauroptera_ _ ___ _ __ __ __ _ __ _ ____ _ __ _ ___ _ __ _ 16 

Glaciation________________________________ 2 

Gomphonema_ ----------------- ___ ------------ 18 

acuminatum _____________________ 8, 18, 19, pl. 3 

act~minatum coronata ___________ 8, 18, 19, pl. 3 

angustatum undulata _______________ 8, 19, pl. 3 

augur ____________ ------------------ 8, 1&, pl. 3 

capitat1tm __________________________ 8, 20, pl. 3 

cons'trictum ______________________ 8, 1P, 20, pl. 3 

cvnstrictu.rn capitata__ _ __ _ _ _ _ _ __ ___ _ _ _ __ _ __ 20 

constricturn capitaturn._____________________ 20 

coronatum ___________ --------------------- 19 

gracile_------------------------------ 8, 19, pl. 3 lanceolata__ _____ ___ _ __ _ __ ____ _ __ _ ___ __ 19 

intricaturn _________________________ 8, 9, 19, pl. 3 

lanceolaturn __________________________ 8, 19, pl. 3 

Gomphonemaceae___ ________ __ _ ____ ____ __ _ _ __ 18 

Gomphonemoideae___________________________ 18 

gracile, Gomphonerna _____________________ 8, 19, pl. 3 

Himatidium ____________ ------------------ 13 

lanceolata, Gomphonema__________________ 19 

gracilis, Eunotia _________________________ 8, 13, pl. 1 

gramtlata, Epithernia __________________________ 21, 22 

Epithernia turgida ______________________ 8, 21,22 

Eunotia ________________ ------------------ 21, 22 

gregoryiana, Navicula bacillurn________________ 15 

H 

Hanson, George F., eited ____________________ _ 

Hantzschia_____ _ __ _ ______ _ _ _ _ _ ___ ______ _ _ __ ___ 22 

arnphioxys ________________________ 8, 22, 23, pl. 3 

capitata ____________________ 8, 9, 22, 23, pl. 3 

major_________________________________ 22 

capitata____ ___ _ _ _ _ ____ ___ __ _ _ __ _ __ 23 

harrisonii, Fragilaria__________________________ 11 

Hendey, N. I., cited__________________________ 23 

heteropleura, Cymbella________________________ 21 

minor, Cymbella_ ------------------------- 20.21 

Himatidium gracile __ ------------------------- 13 

Hixton, Wis __________ ------------------------

Hixton diatom assemblage ____________________ 1. 7, 9 

Hixton diatom.ite _____________________ 1, 3, 4, 5, 7, 8, 9 

Hole, F. D., cited ___________________________ _ 

Hustedt, Friedrich, eited_____________________ 23 

Hydrogen sulfide_____________________________ 5, 7 

impressa, Eunotia ________________________ 8, 13, pl. 1 

pectinalis _ _______ _ __ _ _ __ _ __ ____ __ __ _ __ 13 

pectinalis minor----------------------- 13 

in/lata, Eunotia praerupta ____________________ 8, 9,13 

interrupta, Pinnularia ___________________ 8, 16, pl. 2 

intricatum, Gornphonema ______________ 8, 9, 19, pl. 3 

iridis, Neidiurn_ ------------------------- 8, 18, pl. 2 

vernalis, Neidium ____________________ 8, 18, pl. 2 

Iron oxide____________________________________ 5, 7 

irregularis, Epithemia ____________________ 8, 22, pl. 3 

italica, Gallionella_____________________________ 10 

Aielosira ______________________________ 8, 10, pl. 1 

INDEX 

K 

Karsten, George, cited _______________________ _ 

Krome, Herman, cited ______________________ _ 

L 

Page 

A10 

1 

lanceolata, Gomphonema gracile________________ 19 

lanceolatum, Gomphonema ________________ 8, 19. pl. 3 

lapponica, Eunotia____________________________ 9 

lata, Frustulia ____ ---------------------------- 16 

Pinnularia ___________________________ 8, 16, pl. 2 

leptostanron, Biblariurn_______________________ 11 

Fragilaria ________________________ ____ 8, 11. pl. 1 

rhomboides, Fragilaria _____________________ 8,11 

linearis, Pinnularia gibba______________________ 9 

Loess __________________________________ ------- 2, 3 

Lohman, Kenneth E., cited---------- __ _ 

lnnaris, Eunotia ________________________ 8, 9, 13, pl. 1 

Synedra ___ ------------------------------- 13 

M 

major capitata, Hantzschia amphiorys__________ 23 

Fmstulia _______________ ------------------ 17 

Hantzschia amphio.cys_____________________ 22 

Naviwla _________ ________ --- _ ------------- 17 

Pinnularia ___________________________ 8, 17, pl. 2 

Mankato glacier______________________________ 2 

Mankato outwash ___________________________ _ 

Mankato Stade ___________ --------------------

MarL ____________________ --------------------

martyi, Opephcra ________________________ _ 8, 11, pl. 1 

Meander scars________________________________ 5. 6 

JHeloseira crenulata___________________________ 10 

Aielosira _________ _________________ -------- ___ _ 10 

crenulata ______________________ ------- ____ 10 

italica _____________________ ---------- _ 8, 10, pl. 1 

Melosiroideae __________________ -------------- 10 

meneghiniana, Cyclotella __________________ 8,11,pl.1 

Aferidion_ _ _ ___ ___ _ _ ___ _ __ _ ___ ___ _ ___ ___ _ ____ _ 12 

circu.Zare___ __ _ ____ _ _ _ _ ___ _ __ _ ___ _ ____ __ ___ 12 

cirwlare constricta________________________ 12 

constricturn ___________________________ 8.12. pl. 1 

Mcridionoideae____ _ _ __ _ __ _ ____ ____ _____ _ _ _ _ __ 12 

mesoleptaangusta, Pinnularia ____________ 8,16,pl. 2 

Pinnnlaria __ ----------------------------- 16 

minor, Cymbella heteroplenra __________________ 20,21 

impressa, Eunotia pectinalis_______________ 13 

Mississippi Valley outwash trains ___________ _ 

monodon, Ennotia ___ --------------------- 8, 18, pl. 1 

Monoraphidineae______ _ _ _ __ _ __ _ __ _ __ _ _ __ _ ____ 14 

Moore, R. C., cited___________________________ 10 

N 

Navicula __________________________ ------------ 14 

ambigua _________________ ----------------- 14 

amphibola _________________________ 8, 15, 16, pl. 2 

bacillum ______________________________ 8, 15, pl. 2 

gregory lana___________________________ 15 

bisulcatum___ __ ________ __ __ __ _ _ _ _ __ _ __ _ ___ 18 

cuspidata ____________ --------------------- 14 

ambigua __________________________ 8,14. pl. 2 

dicephala ___ ------------------ ________ 8, 15, pl. 2 

eso.r -------------- ___ _ _ ___ ___ _ __ _ _ __ _ __ _ ___ 17 

gibba_____ ________ ___ ________ _ _ _ __ __ ___ ___ _ 22 

major_____________________________________ 17 

oblonga _________ ---------------- ______ 8, 15, pl. 2 

oblongella____ _ ___ ___ ____ _ __ _ ___ __ __ __ _ ____ 14 

radiosa _______________________________ 8, 15, pl. 2 

reinhardtii_ ___________________________ 8, 15, pl. 2 

rotunda _______________________________ 8,16, pl. 2 

siUwla_ _ _ _ ___ _ _ _ __ _ __ _ __ _ _ _ _ __ __ __ __ _ ___ _ 18 

stomatophora_____ ___ _ ___ _ __ _ ___ __ __ __ ____ _ 17 

trinodis __ _ ____ ___ _ _ _ ____ _ __ _ __ _ _ _ ____ ____ _ 18 

turgida__ _____ _ ___ _ __ _ _ __ _ ___ __ _ __ ________ _ 21 

zebra_____________________________________ 21 

Naviculaceae_________________________________ 14 

naviculijormis, Cymbella ___ ------------------- 21 

Page 

N aviculoideae___ __ _ __ _ __ __________ ___ _ ___ _ ___ A14 

Neidium____ _ __ __ __ _ __ _________ ___ _ _ __ ________ 17 

bisulcatnm _________________________ 8, 17, 18, pl. 2 

iridis _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 8, 18, pl. 2 

vernalis ___________________________ 8, 18, pl. 2 

Nitzschia _____________ ------------ ______ --____ 23 

amphioxys _________________ --------------- 22 

thermalis __________ ------------------------ 8, 23 

Nitzschioideae_____ _____ _ ______ _ __ _ ____ __ _ __ __ 22 

0 

oblonga, Frustulia_____________________________ 15 

Navicula ______________________________ 8.15, pl. 2 

oblongella, Diploneis ovalis ________________ 8, 14, pl. 1 

Navicula _____________ ------- ________ --____ 14 

Odontidium harrisoniL----------------------- 11 

Oneota Dolomite_____________________________ 2 

Opephora____ _ __ _____ ___ ___ __ __ ___ ____ __ __ _ ___ 11 

martyi_ _____________________________ __ 8, 11, pl. 1 

Outwash _____________________________ -------- 2 

ovalis, Amphora_------------------------- 8, 20, pl. 3 

Diploneis ___ _____ ------------------------- 14 

Frustnlia_ __ ___ _ _________ _ _______ __ _ __ _ ___ 20 

oblongella, Diploneis __________________ 8, 14, pl. 1 

p 

Paleoecologic interpretation ___ --------------- 8 

Patrick, Ruth, cited__________________________ 9 

Peat ________________________ ------ _______ -_____ 5, 6 

pectinalis impressa, Eunotia _______ ------------ 13 

minor impressa, Eunotia__________________ 13 

pediculus, Cocconeis ______________________ 8, 14, pl. 1 

Pennales -------------------------------------- 11 

phoenicenteron, Bacillaria_____________________ 14 

Stauroneis ____________________________ 8, 14, pl. 1 

Picea sp ___________ --------------------------- 7 

Pigeon Creek _____ ----------------------------

Pinnnlaria ____________ ----------------------- 16 

borealis _______________________________ 8, 16, pl. 2 

dicephala ______ --------------------------- 15 esor_ _________________________________ 8, 17, pl. 2 

gibba ________________________________ 16, 17, pl. 2 

linearis ________ ----------------------- 9 

interrupta ____________________________ 8, 16, pl. 2 

lata __________________________________ 8, 16, pl. 2 

major-------------------------------- 8,17, pl. 2 

me sole pta ___________ ------- _________ ------ 16 

angusta ___________________________ 8, 16, pl. 2 

stomatophora _________________________ 8.17, pl. 2 

streptoraphe __________________________ 8, 17, pl. 2 

thermalis______ __ _ _ ___ _ __ _ ___ _ __ _ __ _ ___ __ _ _ 23 

viridis ________________________________ 8, 17, pl. 2 

sudetica _______ _ ------- ________ ----- _ __ 9 

sp _________________ --- ________ -------- _ _ _ _ 9 

placentula, Cocconeis _____________________ 8, 14, pl. 1 

Pleistocene terraces _____________ ----------____ 1 

porcellus, Epithemia __ ------------------------ 21 

zebra __________________________ 8, 9, 21, pl. 3 

praempta, Ennotia ____________________________ 9, 13 

bidens, Ewnotia___________________________ 9 

infl,ata, Eunotia _________________________ 8, 9, 13 

Protista _________________ ---- ____________ -____ 10 

Protoctista_ __ ___ _ __ _ ______ ____ __ _ ______ _ __ _ __ 10 

Q 

Quaternary sequence_-------- ____ ------------

R 

Radiocarbon chronology ___________________ 1, 2, 7, 9 

radiosa, Navicula _________________________ 8, 15, pl. 2 

Raphidioidineae ______ ------------------------ 13 

reinhardtii, Navicula _____________________ 8, 15, pl. 2 

8tauroneis ___________ ---- ________ ----- _ --- 15 

rhomboides, Fragilaria leptostauron ____________ 8, 11 

Rhopalodia ___ -------------------------------- 22 

gibba _________________________________ 8, 22, pl. 3 
INDEX 

Page Page 

r:obusta, Eunotia_ -------------- _______________ 9 subsalina, Fragilaria construens __________ 8, 12, pl. 1 

riotunda, Navicula _________________________ 8, 16. pl. 2 sudetica, Pinnularia viridis________ ____________ 9 

rrupestris, Tetracyclus_________________________ 9 Summary of investigation __ --------------- __ _ 

Surierlla solea__________ _ _ _ ___ __ __ ____ _ _ _ __ _ _ _ _ 23 

s thermalis________________________ __________ 23 

Surirellaceae____________________________ __ _ ___ 23 

&alisbury, R. D., quoted ____________________ _ Surirellineae _____________ -------- ______ _ _ __ _ _ _ 23 

Sample contamination_ ______________________ _ Surirelloideae ______ ----------------------- _ ___ 23 

$ample preparation__________________________ 7 Synedra ___________________ ---------------- ___ 12 

8ampling, Hixton diatomite__________________ 1, 7 capitata __ _ ----------------------------- 12, pl. 1 

radiocarbon_-------------- ______________ _ lunaris_ _ _ _ ___ ________ __ _ ______ _________ __ 13 

$andstone ___________________________________ _ ulna __________________________________ 8,12, pl. 1 

~chumanniana trinodis, Caloneis_______________ 18 Systematic descriptions __ -------------------- 10 $chiitt, Franz, cited__________________________ 10 

4cctt, R. A., quoted__________________________ 7 

~ettling time of diatom suspensions _________ _ 

~ilicula, Caloneis __________________________ 8, 18, pl. 3 

1' 

Tabellaria _______ ----------------- __ _ _ ________ 13 

fenestrata __ --------------------------- 8, 18, pl. l 

Navicula ___ -------------------____________ 18 Tabellarioideae__ _ _ _ _ _ _ _ ___ ___ _ __ __ _ _ __ _ ___ _ _ _ 13 

, truncatula, Caloneis __________________ 8, 18, pl. 3 Terrace deposits, formation________________ __ 4 

~olea, Cymatopleura___________________________ 8, 28 'ferraces____ _ ____ __ _ _ _ _ _ _ ____ ________ _ _ _ _ __ _ _ _ 1, 8 

Surirella_ ___ _ _ ___ _ ___ ___ __ _ _ __ _ _ _ _ __ _ _ ___ _ 23 Tetracyclus rupestris ____ -------------------- $overeign, H. E., cited ______________________ _ thermalis, Nitzschia __________ ---------------- 8,28 

Stanier, R. Y., cited__________________________ 10 Pinnutaria_ ----------------------- _ _ ____ 23 

,~tauroneis__ ___ ________ _____ __ ____ __ __ ___ _ _ _ _ _ 14 Surirella______________________________ __ __ 23 

phoenicenteron ______ __ -------- ________ 8, 14. pl. 1 Thickness of strata _____________ ------------- 2, 7 

reinhardtiL _ _ ___ _ _ ___ ______________ ___ ____ 15 Trempealeau Valley terraces ________________ _ 1, 8 

&tauroptera gibba_ __ ____ _ _ __ __ __ _ ___ __ __ _ _ _ _ _ _ _ 16 trinodis, Caloneis _________________ _______ 8, 18, pl. 3 

~tomatophora, Na~icula_ ___ _ ____ _ __ _ __ __ _ _ _ _ __ _ 17 Caloneis schumanniana___________________ 18 

i Pinnularia ___________________________ 8, 17, pl. 2 Navicula _______________ ------------ ______ 18 

~treptoraphe, Pinnutaria _________________ 8,17,pl. 2 truncatula, Caloneis silicula______________ 8, 18, pl. 3 

i 

0 

A27 

Page 

turgida, Cymbella ________________________ 8, 20, pl. 3 

Cymbella (Encyonemal_____ ______ _ ______ 20 

Epithemia _______ ----------------- 8, 9, 21, pl. 3 

granulata, Epithemia ____ ---------------- 8, 21,22 

Nal'iwla. _____________ _______ -------------- 21 

1'wo Creeks Interstade _____ __ _ ___ 5, 7, 9 

u 

ulna, Bacilluria_ ------------- ______________ 12 

Synedra _____________________________ 8, 12, pl. 1 

1tndulata, Gomphonema ang·ust!ltum ______ 8, 19, pl 3 

v Valders Stade_________ ---------------- 5, 9,10 

venter, Fragilaria________ _________ ___________ 12 

construens ______________________ 7, 8, 9, 12, pl.1 

vernalis, Neidlum iridis __ ---------------- 8, 18, pl. 2 

viridis, Bacilluria______________________________ 17 

Pinnularia ___________________________ 8, 17, pl. 2 

sudetica, Pinnularia_________ _____________ _ 9 

w Weathering _________________________________ _ 

Weidman, Samuel, cited______________________ 23 

Whitehall Terrace ____________________________ 4, 5, 9 

Wisconsin Glaciation ________________________ 2, 4, 7 

z zebra, Epithemia ____ ______________________ 8, 21, pl. 3 

Navicula ___________ ----------------------_ 21 

}}orcell·us, Epithemia ________________ 8, 9, 21, pl. 3 

PLATES l-3 
PLATE 1 

FIGURES 1-3. Melosira italica (Ehrenberg) Ki.itzing, X 960 (p. AlO). 

1. USGS diatom cat. No. 3260-207. Diameter, 22p.. 

2. USGS diatom cat. No. 3260-271. Diameter, lOp.. 

3. USGS diatom cat. No. 3260-270. Diameter, 7 p.. 

4. Cyclotella meneghim'ana Ki.itzing, X 960 (p. All). 

USGS diatom cat. No. 3261-.55. Diameter, lOp.. 

5. Cyclqtella conda (Ehrenberg) Ki.itzing, X 960 (p. All). 

USGS diatom cat. No. 3410-62. Diameter, 38p.. 

6. Opephora martyi Heribaud, X 960 (p. All). 

USGS diatom cat. No. 3410-61. Length, 35p.. 

7. Fragilaria leptostauron (Ehrenberg) Hustedt, X 960 (p. All) 

USGS diatom cat. No. 3260-36. Length, l6p.. 

8. Fragilaria construens var. venter (Ehrenberg) Grunow, X 1870 (p. Al2). 

USGS diatom cat. No. 3410-63. Length, l3p.. 

9. Fragilaria construens var. binod1:s (Ehrenberg) Grunow, X 1870 (p. Al2). 

USGS diatom cat. No. 3261-24. Length, l6p.. 

10. Fragilaria construens var. subsalina H ustedt, X 960 (p. Al2). 

USGS diatom cat. No. 3410-3. Length, 35p.. 

11. Synedra ulna (Nitzsch) Ehrenberg, X 475 (p. A12). 

USGS diatom cat. No. 3260-69. Length, 157p.. 

12. Synedra capitata Ehrenberg, X 475 (p. A12). 

USGS diatom cat. No. 3410-41. Length, 197 p.. 

13. Meridian constrictmn Ralfs, X 960 (p. Al2). 

USGS diatom cat. No. 3260-170. Length, 39p.. 

14. Tabellaria fenestrata (Lyngbye) Ki.itzing, X 960 (p. A13). 

USGS diatom cat. No. 3410-25. Length, 72p.. 

15. Eunot£a bidentula W. Smith, X 960 (p. A13). 

USGS diatom cat. No. 3260-256. Length, 5lp.. 

16. Eunotia impressa Ehrenberg, X 960 (p. A13). 

USGS diatom cat. No. 3410-58. Length, 32p.. 

17. Eunotia lunar-is (Ehrenberg) Grunow, X 610 (p. A13). 

USGS diatom cat. No. 3410-65. Length, 125p.. 

18. Eunotia gracilis (Ehrenberg) Rabenhorst, X 960 (p. A13). 

USGS diatom cat. No. 3260-222. Length, 63p.. 

19-20. Eunotia monodon Ehrenberg, X 475 (p.,A13). 

19. USGS diatom cat. No. 3260-229. Length, lOOp.. 

20. USGS diatom cat. No. 3260-134. Length, 66p.. 

21. Eunotia formica Ehrenberg, X 475 (p. A14). 

USGS diatom cat. No. 3260-232. Length, 103p.. 

22. Cocconeis placentula Ehrenberg, X 960 (p. A14). 

USGS diatom cat. No. 3261-106. Length, 34p.. 

23. Cocconeis pedt'culus Ehrenberg, X 960 (p. A14). 

USGS diatom cat. No. 3260-25. Length, 25p.. 

24. Diploneis oval is var. oblongella (Naegeli) Cleve, X 1870 (p. Al4). 

USGS diatom cat. No. 3260-165. Length, 29p.. 

25. Stauroneis phoenicenteron (Nitzsch) Ehrenberg, X 960 (p. A14). 

USGS diatom cat. No. 3260-156. Length, ll6p.. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 523- A PLATE 1 

2 3 

11 

~ g 

8 

[j 

B 

17 

12 

14 

DIATOMS FROM HIXTON DEPOSIT, TREMPEALEAU VALLEY 
Fraun~1 1. 

2. 

3. 

4. 

5. 

6. 

7. 

8-!J. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

17. 

18. 

19. 

20. 

21. 

22. 

PLATE 2 

Navicula cuspidata var. ambigua (Ehrenberg) Cleve, X 960 (p. A14) . 

USGS diatom cat. No. 3260-180. Length, 113}l. 

Navicula bacillum Ehrenberg, X 960 (p. A15). 

USGS diatom cat. No. 3410- 30. Length, 51}l. 

Navicula mdiosa Ki.itzing, X 960 (p. A15). 

USGS diatom cat. No. 3261-136. Length, 66}l. 

Navic1tla reinhardtii (Grunow) Grunow, X 960 (p. A15). 

USGS diatom cat. No. 3260-188. Length, 45}l. 

Navicula dicephala (Ehrenberg) Ki.itzing, X 960 (p. A15). 

USGS diatom cat. No. 3260-80. Length, 39,u. 

Navicula oblonga (Kiitzing) Ki.itzing, X 475 (p. A15). 

USGS diatom cat. No. 3261-127. Length, 125,u. 

Navicula amphibola Cleve, X 960 (p. A15). 

USeS diatom cat. No. 3260-116. Length, 73,u. 

Navicula rotunda Andrews, n. sp., X 960 (p. A16). 

8. Holotype. USGS diatom cat. No. 3260-196. Length, 40,u. 

!J. USGS diatom cat. No. 3260-199. Length, 32,u. 

Pinnularia interrupla W. Smith, X 960 (p. A16). 

USeS diatom cat. No. 3260-4. Length, 78,u. 

Pinnularia mesolepta var. angusta Cleve, X 960 (p. A16). 

USeS diatom cat. No. 3260-82. Length, 58,u. 

Pinnularia lata (Brebisson) W. Smitb, X 475 (p. A16). 

USeS diatom cat. No. 3260-269. Length, about 104,u. 

Pinnularia borealis Ebrenberg, X 960 (p. A16). 

USGS diatom cat. No. 3410-10. Length, 38,u. 

Pinnularia gibba (Ehrenberg) W. Smith, X 960 (p. A16). 

USGS diatom cat. No. 3261-62. Length, 77,u. 

Pinnularia cf. P. stomatoph01'a (Grunow) Cleve, X 960 (p. A17). 

USGS diatom cat. No. 3260-129. Length, 48,u. 

Pinnularia major (Kutzing) W. Smith, X 475 (p. A17). 

USGS diatom cat. No . 3260-96. Lengtb, 200,u. 

Pinnularia esox Ehrenberg, X 475 (p. A17). 

USGS diatom cat. No. 3410-27. Length, 138,u. 

Pinnularia viridis (Nitzsch) Ehrenberg, X 475 (p. A17). 

USGS diatom cat. No. 3260-186. Length, 98,u. 

Pinnularia streptoraphe Cleve, X 475 (p. A17) . 

USGS diatom cat. No . 3260-263. Length, 174,u. 

Neidium bisulcatum (Lagerstedt) Cleve, X 960 (p. A18). 

USGS diatom cat. No. 3261- 88. Length, 43,u. 

Neidium iridis (Ehrenberg) Cleve, X 960 (p. A18). 

USGS diatom cat. No. 3261- 82. Length, 80,u. 

Neidium iridis var. vernalis Reicb elt, X 960 (p. A18). 

USGS diatom cat. No. 3260-43. Length, 60,u. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 523-A PLATE 2 

6 

12 

19 21 

DIATOMS FROM HIXTON DEPOSIT, TREMPEALEAU VALLEY 
PLATE 3 

FwunE 1. Caloneis silicula (Ehrenberg) Cleve, X 960 (p. A18). 

USGS diatom cat. No. 3260-206. Length, 73/J.. 

2. Caloneis silicula var. truncatula (Grunow) Cleve, X 960 (p. A18). 

USGS diatom cat. No. 3410-57. Length, 43/J.. 

3. Caloneis trinodis (W. Smith) Boyer, X 960 (p. A18). 

USGS diatom cat. No. 3260-166. Length, 40/J.. 

4. Gomphonema acuminatum Ehrenberg, X 960 (p. A18). 

USGS diatom cat. No . 3260-47. Length, 40/J.. 

5. Gomphonema acuminatum var. coronata (Ehrenberg) W. Smith, X 960 (p. A19). 

USGS diatom cat. No. 3410-43 . Length, 49/J.. 

6. Gomphonema augur Ehrenberg, X 960 (p. A19). 

USGS diatom cat. No . 3410-56. Length, 42/J.. 

7. Gomphonema angustatum var. undulata Grunow, X 960 (p. A19). 

USGS diatom cat. No. 3260-19. Length, 46/J.. 

8. Gomphonema intncatum Kutzing, X 960 (p. A19). 

USGS diatom cat. No . 3260-26. Length, 54/J.. 

9. Gomphonema gracile Ehrenberg, X 960 (p. A19). 

USGS diatom cat. No. 3260-121. Length, 60/J.. 

10. Gomphonema lanceolatum Ehrenberg, X 960 (p. A19). 

USGS diatom cat. No. 3410-11. Length, 61/J.. 

11. Gomphonerna constricturn Ehrenberg, X 960 (p. A19). 

USGS diatom cat. No. 3260-100. Length, 491J.. 

12. Gornphonerna capitaturn Ehrenberg, X 960 (p. A20). 

USGS diatom cat. No. 3260-147. Length, 491J.. 

13. Amphora oval is (Kutzing) Kutzing, X 960 (p. A20). 

USGS diatom cat. No. 3260-152. Length, 48/J.. 

14. Cyrnbella ehrenbergii Kutzing, X 475 (p. A20). 

USGS diatom cat. No. 3260-237. Length, 147/J.. 

15. Cyrnbella turgida Gregory, X 960 (p. A20). 

USGS diatom cat. No. 3410-67. Length, 45/J.. 

16-17. Cyrnbella americana Schmidt, X 960 (p. A20). 

16. USGS diatom cat. No . 3260-64. Length, 62/J.. 

17. USGS diatom cat. No. 3261-86. Length, 68/L. 

18. Cyrnbella cistula (Hemprich) Grunow, X 960 (p. A21) . 

USGS diatom cat. No. 3410-27. Length, 78/L. 

19. Epithernia zebra (Ehrenberg) l{i.itz ing, X 960 (p. A21). 

USGS diatom cat. No. 3261- 146. Length, 23/L. 

20. Epithernia zebra var. parcel/us (Kutz ing) Grunow, X 960 (p. A21). 

USGS diatom cat. No. 3260- 35. Length, 70/L. 

21. Epithernia turgida (Ehrenberg) Kutzing, X 475 (p. A21). 

USGS diatom cat. No. 3260-17. Length, 120/L. 

22-25. Epithemia. irregularis Andrews, n. sp., X 960 (p. A22). 

22. Holotype, USGS diatom cat. No. 3260-265. Length, 491J.. 

23. Paratype, USGS diatom cat. No . 3410-8. Length, 75/L. 

24. Paratype, USGS diatom cat. No. 3410-44. Length, 75/J.. 

25. Paratype, USGS diatom cat. No. 3260-24. Length, 50/L. 

26. Rhopalodia gibba (Ehrenberg) 0. Muller, X 960 (p. A22). 

USGS diatom cat. No. 3260- 101. Length , 58/L. 

27. Hantzschia arnphioxys (Ehrenberg) Grunow, X 960 (p. A22). 

USGS diatom cat. No. 3260- 107. Length, 72/L. 

28. Hantzschia amphioxys var. capitata Pantocsek, X 960 (p. A22). 

USGS diatom cat. No. 3260- 244. Length, 117/L. 
GEOLOGICAL SURVEY 

13 

PROFESSIONAL PAPER 523- A PLATE 3 

r 

7 

18 

•. 15 

23 

DIATOMS FROM HIXTON DEPOSIT, TREMPEALEAU VALLEY 

19 

=- = · =- = 

====: 

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= 

=