IMAGE EVALUATION
TEST TARGET (MT-3)
li
/.
{./
A
I
I
Q-
C/a
fA
1.0
I.I
1.25
If: iia
■^ IIIIIM
IIM
IIIW
118
U llllli.6
d
w/
Photograpliic
Sciences
Cornoration
23 WEST MAIN STREET
WEBSTER, NY. 14580
(716) 872-4503
A
■17
,\
iV
\\
"%
V
*>
*>
^.
u ..■sis- *
.«^
7v \*^'
/.
**
<?
<^ .%' ids i
r'^
V
^.
'^'fe^
CIHM/ICMH
Microfiche
Series.
CIHM/ICMH
Collection de
microfiches.
Canadian Institute for Historical Microreproductions / Institut canadien de microreproductions historiques
Tachnical and Bibliographic Notes/Notes techniques et bibliographiques
The Institute has attempted to obtain the best
original copy available for filming. Features of this
copy which may be bibliographically unique,
which may alter any of the images in the
reproduction, or which may significantly change
the usual method of filming, are checked below.
n
D
D
D
D
D
D
D
D
D
Coloured covers/
Couver'ture de couleur
Covers damaged/
Couverture endommagee
Covers restored and/or laminated/
Couverture restaur^e et/ou peliicul^e
Cover title missing/
Le titre de couverture manque
Coloured maps/
Cartes g^ographiques en couleur
Coloured ink (i.e. other than blue or black)/
Encre de couleur (i.e. autre que bleue ou noire)
Coloured plates and/or illustrations/
Planches et/ou iliustrations en couleur
Bound with other material/
Relii avec d'autres documents
Tight binding may cause shadows or distortion
along interior margin/
Lareliura serree peut causer de I'ombre ol de la
distorsion le long de la marge interieure
Blank leaves added during restoration may
appear within the text. Whenever possible, these
have been omitted from filming/
II se peut que certaines pages blanches ajout^es
lors d'une restauration apparaissant dans le texte.
mais, lorsque cela dtait possible, ces pages n'ont
pas 6ti film^es.
L'Institut a microfilme le meiileur axemplaire
qu'il lui a ete possible de se procurer. Les details
de cet exemplaire qui sont peut^tre uniques du
point de vue bibliographique, qui peuvent modifier
une image reproduite. ou qui peuvent exiger une
modification dans la m^thode normale de filmage
sont indiqu^s ci-dessous.
D
n
n
Coloured pages/
Pages de couleur
Pages damaged/
Pages endommagees
Pages restored and/or laminated/
Pages restaurees et/ou pelliculees
Pages discoloured, stained or foxed/
Pages d^colorees, tachetdes ou piquees
Pages detached/
Pages detachees
Showthrnugh/
Transparence
□ Quality of print varies/
Qualite indgale de I'impression
□ Includes supplementary material/
Comprend du materiel supplementaire
□ Only edition available/
Seule ddit.ion disponible
D
Pages wholly or partially obscured by errata
slips, tissues, etc., have been refilmed to
ensure the best possible image/
Les pages totalement ou partiellement
obscurcies par un feuillet d'errata. une peiure.
etc., cnt 6te fiim^es d nouveau de facon a
obtenir la meilleure image possible.
I 7] Additional comments:/
i^LJ Commentaires supplementaires;
Pa<)lnation is as follows : [137] ■ 157 p.
This item is filmed at the reduction ratio checked below/
Ce document est film6 au taux de reduction indiqu^ ci-dessous.
10X 14X 18X 22X
26X
30;
y
12X
16X
20X
24X
28X
32X
The copy filmed hora has baan raproducad thanks
to thw ganarosity of:
Library,
Geological Survey of Canada
Tha imagaa appaaring hara ara the bast quality
possibia considartng tha condition and lagibiiiiy
of tha original copy and 'n Icaaping with tha
filming contract spacifications.
Original copies in printed paper covers are filmed
beginning with tha front cover and ending on
the last page with a printed or illustrated impres-
sion, or the bacic cover when appropriate. All
other original copiea are filmed beginning on the
first page with a printed or iiluatratad impres-
sion, and ending on the last page with a printed
or illustrated impression.
The last recorded frame on each microfiche
shall contain the symbol —^(meaning "CON-
TINUED"), or the symbol V (meaning "END"),
whichaver applies.
Maps, plates, charts, etc.. may be filmed at
different reduction ratios. Those too large to be
entirely included in one axpoaure are filmed
beginning in the upper left hand corner, left to
right and top to bottom, aa many frames as
required. The following diagrama illuatrate the
method:
L'axemplaire t'\]mi fut reproduit grice d la
g^nirositA de:
Biblioth^que,
Commission G6oloqique du Canada
Laa imagea suivantea ont iti raproduitas avec le
plua grand soin. compta tenu de la condition at
da la nettet* de I'exemplaire film*, at an
conformity avec las conditions du contrat de
filmage.
Laa axempiairea originaux dont la couvarture an
papier eat impri.mte sont IWmin an commandant
par la premier plat et en terminant soit par la
darniire page qui compone une empreinte
d'Impreasion ov d'illustration, soit par !e second
plat, salon le eaa. Tous las autres sxampiairss
originaux sont filmte an comcnan^ant par la
premiere page qui comporte une empreinte
d'impression ou d'illustration at en terminant par
la derniire page qui comporte une telle
empreinte.
Un dee symboles suivants apparaitra sur la
domiire image de cheque microfiche, selon le
caa: le symbols — »■ signifie "A SUIVRE", le
symbole V signifie "FIN".
Las cartea, planches, tableaux, etc., peuvent dtre
film^e i dee taux da rMuction diffirents.
Lorsque le document est trop grand pour dtre
reproduit an un seul clichil. il est filvni i partir
da I'angle sup^rieur gauche, de gauche i droite,
at da haut en baa. an prenant le nombre
d'images nteeaaaira. Lea diagrammes suivantb
illustrent la m^thode.
1 2 3
4 5 6
M
p
KCBl
V/19
i.'vM
h
-AM
CLASSIFICATION OV THE (^\MH1IIAN SYS-
TEM ov Noirrrr America.
By C. I). Walcott.
IKuoM Till.; AMKiiiCAN JoKUNAi, DK SciKscK, Voi,. X X X 1 1 , Ar.irsT, issr,
\
Art. XYL~ Clossi/icafiov of thr Camhrim, System of North
America f"^- by Charles I). Wai.cott.
The formations included within the Cambrian system in
this p.per ;ne those characterized by the predominence of the
ty[.es of the "Pirsi Fauna "f of Barrande and such additional
2.1,*,'58Sr,.'"^"''' "'" ^'■''*'°"'' '^'"'''"'^' "^ '''"'"""" ""' Wnahington. D. C, April
is Jinr^.uS'o!]' hv .!' Irii'TT'"'' '''"'"V- '^^ "''•'™^'^^' '^^^ f"""'^ '" ^"'•I'l Arnoricn,.
Li- V ^"^ "'"t','' '•"'"" wlHcli, in Uie presence of tl,,. oonera Am.o'^-
,1 «;,-. "" r;-' "'^'"'■""■^' "i<'olIneepI,Mhis. PUehoparin nnd their MJlie,! .enon
(listing.ushes it fn.n, the siiecoe.iinK Lower Sihirian OnlovieiMu) fauna
,
4
!l
'i
C. D. Walcott — Gamhricm System of North America. 139
strata, not characterized by the presence of fossils, as are strat-
igraphically and structurally connected with Cambrian strata
identified by organic remains.
Professor Geikie, in the last edition of his Manual of Geology
(1885, p. 65), has included the Cambrian as a subdivision of
the Silurian system. 1 do not now wish to question the wis-
dom of this for the geologic section as it occurs in England and
the Continent; but of the presence of a well-defined geologic
system beneath the Lower Silurian (Ordovioian) strata charac-
terized by the Second fauna of Barrande, or the Trenton fauna
(including the Upper Calciferous) on the North American con-
tinent, there is little doubt. The geologic sections, given in
this paper, show that it has a total thickness of over 18,000
feet and contains a known fauna of 92 genera, including 393
s|)ecies; that but very few of these species pass up into the
Calciferous horizon of the Lower Silurian (Ordovif^ian), and
that the faunas of the two systems are so distinct in their' gen-
eral facies and also in detail, that they are quite as readily sep-
arated as the Lower and Upper Silurian, Silurian and Devon-
ian, or Devonian and Carboniferous faunas. There is no doubt
that in certain areas the faunas of the Cambrian and Lower
Silurian (Ordovician) systems are intermingled in the passage
beds between the two systems, but the same is more or less
true of all the great divisions of the entire geologic series, from
the Archean to the Quaternary.
Strata of the Cambrinu System.
In beginning the study of the Cambrian system, I looked for
well-defined Paleontologic horizons with relation to which the
various local sections and their contained faunas could be com-
pared. It was evident that the Potsdam faunas of New York
and the Mississippi Valley were at or near the summit of the
Cambrian, but further than that there was little data. Mr. E.
Bilhngs called the Georgia or Olenellus fauna "Lower Pots-
dam," and considered the Paradoxides fauna as of older date :
but, as late as 1885, one of our best-known paleontologists
wrote: "my own impression, at the present, is that tne New
York typical Potsdam is about equivalent to the lower portion
of the Wisconsin areas, and that the Acadian beds of Canada
and V ermont, and perhaps the other Atlantic areas, are not
appreciably different in age, but that the difference in faunas is
more the result of conditions upon which life depended than a
difference in time." (Bull. Amer. Mus. Nat. Hist., vol. i, p.
140, 1885.)
The results of the study of the Middle Cambrian faunas will
appear in Bulletin 30, of the U. S. Geological Survey, and I
have taken much of the data of this paper from the introduc-
UO a D. Walcoit^Caialrian System of North America.
tion of that bulletin. In establishing the strutigraphic position
and paleontologic characters of the Georgia or Olenellus fauna
of th^eM^dSe Cambrian, the key to the succession of the Cam.
briln faunas was obtained, and the sections that are correlated
Table showing the correlationa of typical Cambrian Sections vrtth
referenclto the Potsdam and Georgia faunas of the Cambrian.
ORDOVICIAN or
LOWER SILURIAJJ.
upper I imit of
U p pe r >,ambrian or Potsdam horizo n
UPPER CAMBRIAN
= POTSDAM OR
DICELLOCEPHALUS.
MIDDLE CAMBRIAN
Cer>tral horirnn of Middle Cambrian
.= GEORGIA OR OLENELLUS
LOWER CAMBRIAN
= ST. JOHN SERIES.
NEWFOUNDLAND AND
BRAINTREE, MASS.. OR
PARADOXIDES.
Base of Cambriar<
PRE- CAMBRIAN and ARCHEAN:
1 J- ca^ i\ovpnl'ifpd on the general section with
in the diagram (fig. 1) aie piacea on "^"^ & ,, , Dj^^ello-
relation to the stratigraphic position of Olenellus and uiceiio
cephaluB, or Georgia and Potsdam faunas.
C. D. Walcott — Cambrian Syatem of Worth AineHca. 141
>n
la
n-
The first section (fiff. 2) to which I wish to direct your atten-
tion is that of the Wasatch Mountains, in Utah, where the
Cambrian is well shown in Big Cottonwood Caflon. The
section is described in the reports f>f the Geologists of the
.-l-s-go-^is
with
cello-
.m
o.S
5 ^ "^ o c g *
c 2 ^ •=. s, i (^ '^
■5 = >&^ 22. a
KJ 9. O a >ar3<u
-. m «"-) .s ^^ o
.< •^ C3 a -, , ' CD _c —
3
w cs O „
■!-> q I- a
41 X 5
■s
a • "a -
S2 2^ CjS -cii
<u'a'*a2~££,
„. ^ J JS fe ^ K ~
.S .2 t*,!^ te a .2 5
== t:3 « <? c ifS
afe a-5 .« o fe
o - r — ' -^ P —
00^ a*S
; o =f a > ^
a a- m
a fc- ~ c
o t^ ^^ a
o.s
a o S:5
>,ji
O <-i
•^ .M .M ^ '— t^ **
ao
S§2-
.£ a .
a [J- "^ ^— <:^
c a
SB
o o
Sort •-— S ■"
" V. 9,A 05 S a
a, "- ■ — O _:- rj c3
CO „ - St.
tj a o jS 'E
P -c o c
SsCC
01
CC
i;HK)^C ii^
Fortieth Parallel Survey (Geol. Expl. 40tli Par., vol. i, p. 229 ;
vol. ii, p. 366), but I had the opportunity of examining it more
in detail during the summer of 1885, and through finding the
U2 a D. Wah'ott—CamhHan Si/stem of Nortf, America.
Olenellus or Middle Cambrian fauna, located its upper horizon
and ascertained that the entire Upper Cambrian was absent by
non-deposition, the Silurian resting eonformal.ly on strata of Mid-
die Cambrian age. The section at the base resls on granite near
Hl'^
£5^
. ^ o •- -f .2
"a '^ _. ^ 2 "^
" * » "p ^ ,3
._-o o
<^ * >
= = Q » C ip
~ 3 O _ *
-, ^^ • •- j^ O
.r '"' m o al 0)
- s ■> 5 5?
S ta cs
got
a>
r. S u.
.-2! «r
C - J "■ -="
S- 3 2
■— o c,
- _- © -o 5*2
a - P
■S rt a 5 Q .
^ " « 2 *s u
•S: o S g S t>
•:- ^ « - g
_ 2 3 o
^ « . •- o o
o ra <j< a I- CO
a
o
^ .5 K
i- 5 o
m (a,
a !>0 es
S rr -t
§r^'l|-i
•r -e
S^
CO
.2 -3 « h ■■« :
-«-- 5 CO a
- ^ n o '-i 3 <u
^ " O -^ CO &i *^
^ " = 2 ® § 2
2 ir* ^ - $ -s
O CO ■- g > ~ 5
„ o a> -J i; P S
?^ a a a <^ tt; ~
fcN a y )r tz; ^^ _J^
a *. 2 £ ® .2 iJ
a as K a o CO
the mouth of Big Cott^ mwood Cafion, and the strata continue up
tbe caSon in an unbroken, conformable series of siliceous rock
snales, quartzites and sandstones, until 12,000 feet in thickness
I
* 1
oa.
C. D. WuJcott—Cuinhrian Si/stcm of North Am
erica.
143
rizon
tit by
Mid.
near
up
ck,
ess
IS passed through. In the upper 250 feet of silieo-arcrillaceous
shales that rest on a massive band of quartzite, 8,0n0 feet in
thickness, the following fossils occur: Cmziana?, Linrfulella
Ella, Kutorgina pannula, Ilyolithes BilUnr/si\ Leptrdltia Argenta,
Oloiellus OUhertl, Plychoparia nuadrans and liath>i>inscus pro-
duda. This fauna is also found at a similar horizon in several
localities in Nevada; and the lithologic, stratigraphic and
paleontologic evidence, as found in the Oquirrh and Tintic
ranges of Utah and the House, Eureka and Highland ranges
of Central Nevada, extends the same horizons throughout the
western and southern portions of the Great Basin area.
The entire absence of fossils in the lower portions of the
Wasatch section may be owing to the character of tlie sedi-
ments ; but an attempt is made further, to explain the absence
of the Lower Cambrian fauna of the Atlantic area.
The second section (fig. 3), that of the Eureka* District, by
Mr. Arnold Hague, stratigraphically overlaps that of the
Wasatch, the lower 1,500 feet of quartzite corresponding to the
upper-half of the 3,000 feet of quartzite of the Wasatch sec-
tion, and the Olenellus shales occurring at the same horizon on
the summit of the quartzite; but here the Lower Silurian
(Ordovician) strata do not rest on the siliceous Olenellus-bear-
ing shales, but are separated by over 6,000 feet of limestone
that carries a fauna uniting the Middle Cambrian fauna with
the Upper Cambrian or Potsdam fauna, which begins in its
characteristic forms 4,500 feet above the 01enellu°s horizon.
One hundred miles south of Eureka, in the Highland Range, f
found the Eureka section essentially repeated and identical spe-
cies occurring at the same relative horizons in each section.
The vertical range of the Eureka section embraces the corres-
ponding strata of the Highland Range section and several sec-
tions that occur in Nevada and Western Utah,
Section No. 3, fig. 4, is unlike either of the first two sections '
in having the Upper Cambrian well developed, and the Middle
and probably the Lower Silurian (Ordovician), entirely absent!
This section is beautifully exposed in the deeper portions of
the Grand CaSon of the Colorado, Arizona, and was first made
known in a general way, througli the explorations of Major J
W. Powell in 1875. During the winter of 1882-83, Major
Powell instructed me to make a detailed section of the strata
in the depths of the cafion, and fig. 4 is one of the results of
tue work. The Upper Cambrian, or Tonto formation is 1,000
feet m thickness, composed of siliceous and calcareous strata
and carries a fauna that unites it closely with that of the Upper
Cambrian of Nevada, Texas and the Upper Mississippi Valley.
Beneath the Tonto there is a great mass of strata, over 12,000
feet in thickness, that are unconformable to the horizontal Tonto
U4 a D. Wahoti-Camh'ian Sudem of Sorih America.
1 ♦» « Ki.rVilv.inclinea (Huroninn?) strata beneath,
strata above and the J^'K'h^ " "^^^^^^^^^ ■ ^ ^\,^ Cambriun
I have hereto ore re; er d ^^^^^^^ J^" ,^ W scor.sin and LUuio
1.2 11111
_ O tn as
55
' -, S ft tf. _!
5 ,2
B Zi j: -z --^ '" ^
5 >. 3 >. 5 7 ®
f.'TS
O - *j £ O 3
s' « i y r-r = ii
b M B ^ U = .C
3 -C — t ' J3 — -^
■if-^^;: 2 2
*j c: ^ 'X3 <i.
- -o ^ § "^ S -2 2
"« '-' o '-S H '►^ ■?: 'b
- H ►■ -^
o ^ OS P -^
- -> r^ _ g
P « 2 'S :S ■'
a o "-^ *
1 ts X e
9
•« :; s ii -S - ^-
_os®;S"5aJ„^
5 2 c! "" c 3 3
^ a 'S 2 5 2 2 ?,
^ " S( o
I JO 2 ^ o K-<
Or
'- a - >, 2 ^ 2 o
5 '2 o S ^, ~ « o
Mo jjji a g 5 o
^ I? S ?§ J "s -i I
i
(
<< „„i AocTVPP with the Cambrian,
pre-Cambrian and a system of equal ^^SJ^^/^^^'^^.e the strata
Lwer Silurian (Ordovician), etc J^ JJ^^ ^^ ,,ith theHuro-
below the Grand CaSon senes will be ^one\^l\^^^^^^^ ,^ .gain
nian of the Wisconsm section, i his wu
' C
\'
h.
in
no
6
! 2
i
-»
ibrian,
1 strata
! Huro-
» again.
C. I). Walcott^Camhnan Syatem of North Anurloa, 145
The Grand Canon section is typical and iticludos with it the
Cambrian section of Central Texas and Northern Wisconsin
(see figures 5, ♦»).
Crossing to the eastern side of tlie Continent, our next sec-
tioii (fig. 7, p. 148) of the Cambrian strata is taken in North-
western Vermont, and its contained faunas icrvo to connect the
distant Nevada sections and the group of Cambrian sections
along the St. Lawrence, Champlain, and Hudson River Valleys.
At the base of the section a massive belt of limestone, 1,000
feet in thickness, carries in its upper portions the Olenellus
fauna which, in the argillaceous shales capping the limestonch,
attains an extensive development. Continuing up in the sec'
tion through the argillaceous shales, about 2,000 feet, masses
■ <^^^.
Fig. 5.— Section in Llano County, Tcxns, sliowin^ W\v, rolationH of tlio Upper
Cambriiin (Potsiiatn) and the pre-Cambrian Llano Series.
of limestones are found interbedded in the shales, and in the
limestone fossils that show tbe near approach of tl e Upper
Canibrian or Potsdam fauna. The section gives the same suc-
cession of fauna as the sections of Nevada, where we find posi-
tive stratigraphic proof of the great difJ'erence in age of^ the
Middle and Upper Cambrian faunas.
The Georgia, Vermont, section includes, in its vertical range,
the sections about and below Troy, N. Y., in the Hudson Rivet-
Valley, and those of Northwestern Newfoundland and the
Straits of Belle Isle.
Directly east of the Adirondack Mountains of New York,
t!ie ''otsdam sandstone is overlaid by a stratum of shaly
arenaceous rock full of fucoidal, or annelid markings, and there
the Chazy limestones appear resting on the latter.* Tracing
the sandstones south, a fine exposure is seen at Ausable Chasm,
and continuing south a limestone is found coming in on top of
the sandstone that, in Saratoga County, contains a well-marked
fauna of twelve species, four of which are identical with species
in the upper beds of the Wisconsin Potsdam sandstone. The
calcareous layers of the Potsdam also occur at Whitehall, and
Professor Dwight has found them near Poughkeepsie.
* The unconformity, by non-deposition, noticed by Sir William LoKfii:, is
nowhere better illustrated than at this point, the Calcifcroua forinuti.)n beinir
absent from the section.
■
146 C. D. Wahott—Camlmcm System of Is^'oHh America.
>, <
\
Durincr the deposition of the Potsdam sand-
stone the shore-line was close at hand, and the
Adirondack area famished material for the
formation. Out from the shore-lme the mud
and sand were mixed, and stdl farther out,
over the present area of the Georgia section
the shales with interbedded limestones po; it
to deeper, quieter waters. I have yet faiied
to find in Vermont any Potsdam sandstone
north of Burlington; and the evidence goes
to prove that the ui)per portion of the Teor-
cia section, with its shales and "lentiles
of limestone, is equivalent to the Potsdam
sandstone about the Adirondacks.
We have now hastily reviewed the princ ■
pal sections of the Cambrian under which
all the others now known can be groupea
except those of Braintree, Massachusetts, bt.
John New Brunswick and the southeastern
Newfoundland sections. These are not con-
nected paleontologically with the more west-
ern section and we distinguish them as the
Atlantic border sections, and mostly ot older
date-- than the strata of all but tl^e lower
■ portions of the Wasatch, and perhaps the ien-
i nessee sections. As the position of the At-
i lantic border Paradoxides fauna is determined
^1 on paleontologic evidence, the discussion oi it
"^ ? will be taken up later.
•il In the following table, the writer expresses
- II his view of the dassification of the various
M^ formations that go to make up t^e Cam-
s '; s brian system of North America. It is hub-
Sitlject to revision in details, but the main
t? 1 -= divisions are based on pa eontologic and
^-1 stratigraphic data, that I think w^"/'.^/'/
-I them of service in the permanent classihca-
t § % tion of American Paleozoic rocks.
2 1^ It is not claimed that the arrangement of
e ^ " the formations in the following table is orig-
I -^1 inal with me, as, with some changes in nomen-
8 ^ -o clature, it is the same as that to be found
I on page 40 of the Report of the Geological
of the Cambrian ^^l^tem. fo'i^; ' - J'''l '^^^^^ predominates^, and the upper faunas
-•^^^ '""; ^T'^^^^^Z^^W^^oC^^^^ Atlantic than to the interior
Si,i:7uSi;^.-;'!x;::" l nnd a numher of species common to each.
o
\
C. D. Walcott— Cambrian System of North America. 147
Classip'catiou of North American Cambrian Rocks.
Lower Calcifer-
ous.
ri'CKR CAMBHIAN-.
Lower portion of the Calciferoua ibrnintiou of
New York and CannJa. Lower Magnesiaii
_oMVisoonsin, Missouri, etc.
Potsdam of New York, Canada, Wisconsin,
Texas, Wyoming. Montana and Xpvada :
Tonto of Arizona : Kno.x Slialos of Ten-
nessee, Georgia and Aialiama. The Ala-
bama section may extend down into the
Middle Cambrian.
Georgia formation of Vermont, Canada and
New York.
Minni-K CAMiiRi.w.^'-'^"'^'^ '^" ^°"P- Limestones of L'Anse an Loup, Labrador.
Lower part of Caiiil)rian section of J'hireka,
and Highland Range, Nevada. Upper Por-
tion of Wasatch Cambrian section, Utah.
Paradoxides beds of BraintreeTMassTTsr.
John. New Brunswick. St. John's area of
Newfoundland. Lower portion of Wasatch
section, Utah.
The Ocoeo conglomerate and slates of East
Tennessee a re doubtfully included.
LOWER C.VMIiKI.V.N'.
Prospect.
8t. John.
Braintree,
Newfoundland.
Wasatch.
Tennessee.
Survey of Newfoundland for 18<i5, published in 1866, by Sir
William Logan, and based largelv on the paleontological work
of Mr. E. Billings.
Fauna of the Cambrian Syi^ton.
As has long been well known, ihe Trilobita form by far the
largest portion of the Cambrian fauna. Of the ninety-two
genera and three hundred and ninety-three species known to
nie at present from the American Cambrian, 31 genera and 226
species are pla-ed under the Trilobita, and 61 genera and 167
species under all the other classes. The Brachiopoda come
next with 15 genera and 67 species ; Crustacea with 10 genera
and 15 species, etc.
In the accompanying table a summary is given of the Cam-
brian faunas of North America, as far as known to me, up to
the present date. A critical study of the Upper Cambrian
taunas will eliminate some of the genera and species and, also,
add others. The study of the Lower Cambrian fauna of New
Brunswick is now being carried forward by Mr. Ct. F. Matthew,
and that of the Upper Cambrian by myself; and probably
within two years the Cambrian fauna of North America will
include more than 100 genera and -100 species, as to-dav there
are 92 genera and 398 species published, that I have included
in the fauna. There are a number of genera and species not
included that do not appear to be based on organic remains, or
are synonyms of some of those that are included.
A.M. Jouii. Sci.- Third Series, Vol. XXXII, No. 188.— Aro.rsT, 188(1.
10
148 C D. WaJcott — Camhrian System of North America.
Geologic lilsionl.
l'l)ix'r Cambrian .
Middle C'aiiibriai)
Lower Cambrian
Rcap})oarances
Total i'auna
(ieiicra.
52
43
32
J27
35
02
i-'pecies
213
107
tt
3116
3
393
\
C D. Walcott—Camhrian System of Xorth A
Zooloiilc lilisiime.
Algie *^'^°f ""a
^I'ono-ijD i
Hydrozoa "
Ci'liioidefi "" ,
Annelida ^
Brachiopoda "
Lanu'IIibranc'liiata ...^ ...'"!.. \
Gasteropoda , .
Pteropoda *
Crustacea n f
Pnecilopoda i]
m erica. 149
species.
9
13
6
3
5
67
1
29
20
15
226
9'' SO'^
There are 14 genera common to the Lower and Middle Cam
hr,nn : lo common to the Mi.ldle and Upper a'rabr an il
cc.mmon to the Lower, Middle and Upper Cambrhnond M
common to the Lower and Upper Cambrian. ' '"^ ^^
( )f he 52 genera in the Upper Cambrian, 17 are much more
strongly represented m the second fauna, viz : Lin.ula Zs
Leptaena Tr,ples,a, Bellerophon, Euomphalus, HolopVi Ma
of !ts^?au„a"''""'' "' "°' '"""■''''"'' "^ " »" "l^^^cleHllic
mn!l''^f"^."°™'''"^",'■'"'^"'^''''= »"'' paleontologio study is
m. vie of the passnge beds between the Cambrian and Lowe?
zti^^. '"If" "pf^-.'>^hVi^re't'he%r.r-^^
the two systems. At present it is to a large extent wanting
6nf»i fawjia^.-Tha the stratigraphic position of the Mh die
of the Potsdam fauna is shown by the Eureka and Hicrhi.nd
monf '^n'^ '' d" ^'"^'^' "^^ '''' ^^<^'-«-^ section i'°''C
mont. In Nevada, in two sections unbroken by faulting or
o e'hLlr'r ^nd'^^trVT^'^^'-^ a geographi; dTsi^nc^e o
9nnn f innn'r ,^"enty-five miles, the fauna ranaes from
2,000 to 4 000 feet below strata carrying a typical UpSer Cam
b nan, or Potsdam fauna. But threi species, Voto^Ca % "
estrata, Acrotreta gemma and Stenotheca elougata !4eTnown o
Fss up to the Upper Cambrian or Potll m horizoT I,i
the Georgia, Vermont, section, one of the sj^ecies P/^coVa
150 6'. D. Walcott—Camhr'um System of North America.
\,h,,„,i -.nnears to pass ui) into the Potsdam horizon of the
; Son ;E",e\lna is ^more like that of the Potsclan^ and
of the other species, Orthishm Orientahs is niuch ike 0. Fepom
of the Potsdam sandstone of AV^seonsin : b^^^the fauna a. a
whole IS so clearly distinct from the typical Potsdam of ^ew
Yo?10Visconsin, 'Tennessee, Alabama, Texas, An.ona Nevada
and Montana that, even without any section to show their rela-
tions to each other, I should not think of correlating them as
contemporaneous faunas. ,,.,■,, /->, • c v^
The stratigraphic relations of the Middle Cambnan fauna to
the Paradoxkles fauna of St. John Braintree and Newfound-
and are not so clearly proven as for the Middle, and Lpper
Cambrian faunas. Tlie only locality known - -- jhe two
faunas are in the same geographic area is about Concep tion
Bav Newfoundland. At Topsail Head abou UHJ_ teet ot
Sstone is exposed, overlaid by dark shale. AH stratigra,^iic
connection with other sections in the vicinity is broken. The
fossils in the umestone are not numerous, but Mr. Bdbngs pio-
nou need them Potsdam (Geol. Newfoundland p. lob, repnn
o^Tport for 1868), and identilied Saltereda Cr«;ua (prolmbly
Kutoljma) Lahvadoriccu and I found, m the col ection of the
Geological Survey of Canada, SceneVa reliculata, ^^tenoth^
rugosa, Iphidea bella and Protypus senectus ^^%.^f ^/f "^j;^;^^^^
gives six species that are also known from the Middle 0am
b 'an horizon of L' Anse au Loup.^ Special stress is placed by
the writer on the occurrence of these fossils at Topsail Head
as it is in the midst of the Paradoxides basin. Mr. Alexande
Murray correlated the Topsail Head limestone w i h that of
ot er localities, and places it beneath the Paradoxides-bearing
shales of St. Mary's Bay (on the page cited above), but without
p'deontologic or stratigra, c evidence that can authorize him
to ^ay more than that a supposed connection is indicated.
Not having stratigraphic evidence o the relation of tlie
Geoi-ia or Middle Cambrian fauna and the Paradoxides or
Lower Cambrian (Ordovician) fauna other than that they occur
Tn the same area and are not in the same stratum of rock, we
turn to the faunas to aid us in the settlement of the question.
Of the thirty-two genera of the American Paradoxides hori-
7on fifteen pass up into the Olenellus horizon, viz: Arenico-
mes, Ssi^ongia,^rch.eocyathns?, Eocv-stites ? ?, Linguel o,
Ac otreta, Acroihele, Kutorgina, Orthis, Stenotheca, Ilyolithes
Aonostus Microdiscus, Solenopleura, and Piychopar.a. Of
these, eleven, Arenicolites, Protospongia, Lingulella, kutorgnia,
A^otreta, Orthis, Hyolithes,. Stenotheca,. AgnostusM^^^^^^^^
cus? and Ptychoparia, continue on up into the I otsdam oi
* \[r BiUines ealkMl all the Mi(Mle Ca.ubrmn fauna - Lower I'oisclam/
explains his rcfernng the Topsail Head fossils to the Potsdam.
which
\
C. 1). Walcott—Camlrian System of North Amerim. 151
Ui.l)er Cambrian honpcon, leaving but four genera that are
alone common to the Middle and Lower horizons. One genus
Dendrograptus, is doubtfully identified in the ParadSxides
lon^ion ot New Brunswick thai occurs in the Upper Cam-
brian, and is, as yet, unknown in the Middle Cambrian The
genus Agraulos IS also found in the Lower and Upper, but
not in the Middle Cambrian. Of species, not one of the 76
. ^ ^r"\®!','^"^ ^°'''^'' Cambrian fauna are known to occur
111 the Middle Cambrian fauna, which, with its 107 species
stands out clearly from the older fauna and also from the more
recent Potsdam fauna, as but three of its species, Protosponaia
/enestraia, Stenotheca elongata and Acrotrela qemma, are known
to occur in the Upper Cambrian, and l(i of the genera in the
Middle Cambrian are not known to pass up into the Upper
Cambrian or into the Lower Silurian (Ordovician) faunas Not
one species is known to be common to the Lower and Umer
Cambrian horizons.
Having studied the Middle Cambrian fauna more thoroucrhly
thiin that of the lower and upper horizons, I will speak of it
on that account and, also, from the fact that its character and
geographic distribution is not as well known as the other two
As a whole, we notice that it combines the characters of the
Lower Cambrian and Upper Cambrian faunas and yet is dis-
tmct from each of them. There does not appear to be an
equivalent fauna in the Cambrian system of Europe either in
Jiohemia the Scandinavian area, or in Wales; but from the
Island of Sardinia, Dr. Bornemann has described a groui^ of
sponge-like bodies closely related, if not identical with Ethmo-
phtjUumiiwd ArchcBocyathus of the American Middle Cambrian
fauna; be also names Kuiorgina cingulata which is found at
this horizon both in Vermont and Labrador. A species of
tnlobite IS referred to Olenellus, but I have not seen any illus-
tration of it.
Tlie conditions that developed the Middle Cambrian fauna
ai^pear to have been largely peculiar to the American continent.
i)unng the depo.sition of the St. John's series of the Lower
Cambrian, or the Paradoxides strata, we learn from the Euro-
pean and Eastern American sections, that the fauna was essen-
tially of the same type over the entire basin (Atlantic), and
from evidence known to date, that the fauna did not extend
west of a line passing northeast through f:astern Massachusetts
to A'ew Brunswick and Newfoundland.
That there were deposits of sediment to preserve the fauna,
if it extended westward, is shown by the thousands of feet of
sediments below the Middle Cambrian faunas of Utah and
Nevada.
From the data we now have, I think that during the exist-
152 C. D. Walcott — Caiabrian System of North Amerioa.
ence of the greater portion of the Lower Cambrian (Parudox-
ides) fauna, a barrier existed that prevented its extension west-
ward of the line mentioned ; that towards the close of the time
of the Paradoxides fauna that barrier was removed to the
northeast, in the vicinity of Newfoundland, and the descend-
ants from the Paradoxides fauna entered the westward seas and
spread to tiie eastern and western ])asius and formed the Middle
Cambrian fauna. What route was taken by the Middle Cam-
brian fauna after passing to the western side of the outer
barrier is not yet traced, but I think from the indications we
now have of a continental area, during Lower and Middle
Cambrian time, in the central portion of the continent, that the
fauna passed to the south around the southern end ot the then
existing land, and thence north along the west shore. In the
Atlantic basin, the Paradoxides fauna persisted to a greater or
less extent and mingled with the types of the Upper Cambrian
fauna as in the Upper Lingula Flags of Wales.
If this is a correct interpretation of the evidence now known,
we may look in vain in the central interior basin for the Para-
doxides fauna of the Atlantic basin.
That there was life in the older Cambrian or pre-Cambrian
seas of the central interior basin, there is no doubt, as we have
found traces of it in the Grand Canon section of Arizona ; and
the development of that fauna which from the stratigraphy is
pre-Cambrian, is one of the problems awaiting solution.
During the Upper Cambrian (Potsdam of America; Upper
Lingula Flags ot Wales), the Atlantic and Pacific basins ai)pear
to have had free communication with each other, and the
faunas now have a facies of the same general character.
The above views are, to a certain extent, theoretical, but the
facts demand an explanation other than that the faunas of the
Lower, Middle and Upper Cambrian were contemporaneous
but in different geographic areas. That the upper and middle
faunas were separated by a great interval, is shown by the sec-
tions in Nevada and Vermont; and that the middle and lower
faunas were not contemporaneous is shown by the biologic
evidence and the indirect evidence of the absence of the lower
fauna in association with the middle fauna in the Newfound-
land area, where they are now found in different strata, but a
short distance from each other.
A diagram illustrating the Cambrian sections of America and
Lurope would show, in the former, that the sequence of life is
divided more sharply into three great groups that, in the
latter, are more or less broken up. First: by the nearly entire
absence of the middle group, and secondly, by the commingling
of the upper and lower groups in the European strata and pos-
sibly in the Atlantic border sections of New Brunswick and
a D. Walcott- Camhrian System of NoHh America. 153
Newfoundland This subject will be treated in detail after the
con^leuon ot the study of the Upper Cambrian faunas now in
a..tfrl 'p''^:''^"^^^^, mentioned, I have heretofore included the
Grand Oauon and Llano series as, in part, of Cambrian -ure and
correlated them with the Keweenaw series (Bull YI Phfl'soo
I"e'm?f b'e'nWed''''.^- '" ^'^P'^"^' ^'^ vieV't^it'alfo'f
cnese may be placed under a system of preCaml)rian ipp t
tlnnk there ,s good reason for ft in the pWnce o the Irkt
s" en *Tn f 'th^ ero^on, between the strala of the KeweeTaw
^e^of tt utt r' T'^' ^^^t^overlaid^VthTh'^rfzSS
Grand C.LnTV ^^.7'"' ^"'^ '" the Keweenaw, and the
separated ?rom h.'T'' r' ^^f '^[^'^ °^ ^'^'^^^ ^^ i» ^"rn
nT Srand r.Hn" ^ ^'^°'" V "" ""conformity that,
o?.o i " °'^"' .^.^ ''^'■^ g''®^*' and in the Lake Suoerior
area sufhc.ent to indicate an orographic movement Sous
sec 'oL rf r\' n''' """"^"f %«• ^^^ three'^^JZ
sections (tigs. 4, 5, b) agree in the evidence of an extended
orographic movement and a great period of erosion at the close
of deposition of tlie Keweenaw series; and I am now of the
opinion that the Keweenaw system should be considered as
pi^-Cambnan. The correspondence in the position of the pr^
Grand Canon strata, separated from the Grand CaSon series Tv
a grea unconformity, to the Huronian as described ^^0^
IS so striking that more than calling attention to it is LneceS
The presence of organic remains does not necessarilv implv
Uiat the strata are of Cambrian age except they show amLXd
Cambrian facies; and unless this is the case I shouTd "orcon
tend for a moment against well-proved stratigraphic evidence
of greater age and marked structural breaks in the stiati" aphic
succession. It may be asking too much for the period ifem
to say that 12,000 feet of mechanical sediments and 4 000 fee
of limestone accumulated in the Utah-Nevada basin while this
erosion was taking place: but, if we look higher up n the
?00"ee?ofsir''^'"' 'ri'^^' "^ ^^"^'-^l ^^^^^''^' ^-- fin " tha?
200 .eet of Silurian and Devonian strata in the former is repre-
TotJS^ Keweenaw system is here used to include the Keweenaw series of thp
Lake Superior region, the Llauo series of Texas and the Chnnr «nH r! ^ n *
154 v. D. Walcott—Camhrlan System of North America.
sentative of the 13,000 feet of limestone of the same formations
in Nevada, and no unconformity, by any extensive erosion, is
indicated ; and, again, the 9,000 feet of limestone of the Upper
Cambrian and Lower Silurian (Ordovician) of the Central
Nevada section is unrepresented in the Wasatch section of
L, tah. 1 hese facts readily prepare us to believe that the hiatus
between the Keweenaw and lJi)per Cambrian is fully equiva-
lent to the period of the Lower and Middle Cambrian
Another reason is that from the extended orographic move-
ment preceding the erosion of the Cambrian, we should expect
to hnd evidence of that erosion in the Cambrian of Utah and
iNevada, but, as vet, none such is known
Thus far the question of the existence of the Keweenaw sys-
tem has been treated from a purely structural basis,* but in
the course of my study of the distribution of the Cambrian
faunas I have met with some facts that require an explanation
and the most plausible one demands the existence of an ex-
tended orographic movement, prior to the deposition of the
Cambrian strata of the western side of the Continent, that raised
a land area over the central portion of the Continent which
T^\t p V° l^' PT^^ °^. *^^" beginning of the deposition of
t P wS nf T """^ ^°™f ons, when it was depressed beneath
o^er^ortionsof r '"' ^^^ ^PP- ^-brian strata deposited
The facts demanding explanation are: 1st. The entire ab-
sence as far as known to drite, of the Lower Cambrian or Para-
H?;^Mn li"n '1'' ""^ ^'^^.^tlantic border: 2d. The absence of
by the formations of the Keweenaw system
• If we accept the view that the Keweenaw, Grand Canon, and
Llano strata are outcrops of a system of strata of pre-Camhrian
age that extended, in connection with the Huronian and Lau-
rnHv'nf r'f >\^»^, P'-oJecting up through it, from the great
body of Archean land on the north, southward over the area
now occupied by the central portions of the Continent, or the
Mississippi Ya ley and westward to the area occupied bv sedi-
ments accumulated on the western side of the Keweenaw svs-
tem of strata when the latter formed a land area, then the ex-
planation asked is given. The pre-Keweenaw portion of this
tZTl r^- """'i have been extensive as, in the Missouri
aiea at fet. Lou,s and the Ozark Mountains, the Arcnean ap-
pears beneath the Upper Cambrian ; and all ihe eastern slopes
=»rir'*!?f •*^'" ^; C- pli'-J'^'jerlain gives a most excellent summary of the Keweenaw
series and its strat.graphic position in vol. i, of the Geology of WisconsTn la
the ection, on page 65, it is placed as a distinct system, Sting unconfora^ibly
fornitv C'r" T'"^""'-'" turn, is separated from the L^urenti^n by 4 mS
J
j
f
V. D. Walcott-CunMun iiystan „f North America. 155
»ame i, tme in ti.e Black Uilis:;""T„^l"„f^;;S;. ™%t
s &.
5i;i!!'iiiiiiii!!iiii^:: s ■■ ,
eastern belt is strongly imlcSibv the' J^po^ 1. ' ' •^"•'*' P'"^'^"^'' "^ "^^
faunas. L, Laurentia'n and ot Ir Vr LTu S ' b^^^ "' *^ ^^^'^^'^^
formation; C, Grand Canon formatio V v v ' Keweenaw; T, Llano
land surface but now oonee'SeS b^tl^Vd^^po.^ts ' ''"'' "''^^'''^ *° '^'^^'^ '^^^^
existence Of these Archean areas with the U", -r Cumbrian
deposits proves the early date of their elevation, .d tL^t the?
15(5 C. D. Wdlroft — CtDnh'lan System of Xorth AtneHca.
were the shore line of the pre-Canibrian Keweenaw sea. What
the eastern boundaries of this sea were, we do not now know,
but the inference, from what is known
of the Archean of the Appalachian
system, is that portions of the latter
were above the ocean during the depo-
sition of the Keweenaw system.
The traces we now have of this Ke-
weenaw land point to its exteiision
from the Lake Superior region soutii
to Central Texas and westward to
Central Northern Arizona. A glance
at the map (fig. S) shows how far
apart the relatively small exposures
are; but, the great similarity of the
sections and their position in relation
to the Upner Cambrian that rests on
the eroded surface of each visible area,
points to a wide spread orographic
movement that raised the entire cen-
tral portion of the Continent and again
depressed it at the termination of the
period of erosion preceding the deposi-
tion of the Upper Cambrian or Pots-
dam sediments of the Upper Missis-
sippi Valley, Central Texas and Ari-
zona.
The existence of such a land over
the area mentioned, is shown by the
sections we now know; and I think
that, when the areas of Cambrian and
Archean rocks in Missouri and also
along the Southern Appalachian chain
come to be studied with the view that
such a land existed during the period
of the deposition of the earlier deposits
■^ a g J . of the Cambrian system, evidence will
•|l^g be forthcoming to show its former
^■i^Z presence over a large area. On the
-i'lJs;^ "orth it probably joined the Archean
|2|§.a continent and thus gave a greater ex-
^ j.3bc| tension of the pre-Cambrian continent
^ti|lf *^ ^^® south that, during the early
'*'"'' I i [history of the Cambrian period, fur-
'^-^ ished more or less of the sediments of
the strata of the Lower and Middle Cambrian. The Archean
boundaries of the Keweenaw sea continued after the elevation
^ 'i i
at? =s
^i a
K ^ " a
4> C " -2
3 M 2 j;
y
(' J). Wolroff~(',ti,ih,-;,ni St/Mfr7n of Novih A
nwnco.
ir.7
./
o( I.Im« Iscvv.'ennvv liin.l. When Kowccnjiw land is spoken of
I n'l.i- to that fonnwl of the strata of tlio Kciwoonavv systiim
and t ic Ar(rli(>!in n.cks with vvliicli it was associatcid.
He. ore tlio K(nv(u>naw hmd was dnprcsscd the MiddU; Cam-
hnan fauna passed through or around the barriers hotween the
Ath.ntic and western seas, and, as tl)e Keweenaw land was dia-
!'PI"'-i]'"'M hen.'ath the waters, the Ui)per Cainhria!. fauna
spread .)ver the area oeeuj.ied by it and l(>ft its record to aid
lis 'u fixing the geologic date of the sui)niergen(!e < f the
Kevvej-naw land and to ex|)]ain the absence of the l'ara(h)xides
or Atlantic laiina in the earlv ( 'ambrian strata of the western
sule of the Continent. In ti.e diiigrainatie section (fi<^ !>) J
hnvo eiideayore.1 to show the relations of the Potsdam 'or
Upper Carnbriaii to the Keweenaw land.
'I'he evidence of tli(! existcM.ce of the Keweenaw land i.s both
alratigraphic a.nd paieontologie. ^IMiat life existe<l in the seas
at the tune o( the deposition of the sediments of the Keweenaw
system IS shown by its presence in the Chuar formation of the
(jrand Cafion series.
It may be urged that there is too much theorizing, on insuffi-
cient datn, in the f)receding statements, but, while waitin«' the
acciimuialion of evirlence it is well to have a workincr theory
and as such the " pre-Cambrian Keweenaw land " is m-oposed
and th.! fragmentary remains, less the Archean r)ortions, called
a '•iM-e-Caiiibrian i'aleoj^oic System."