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Art. XI. — The Occurrence of Coral Reefs in the Triaesic
of North America ;* by James Peerin Smith.

The occurrence, in the strata of past ages, of reef-building
corals of modem groups gives us our best record of climatic
conditions in those times. The modern reef-builders are now
confined to the tropics, and it is only reasonable to assume that
they have always been confined to regions where the waters
had a tropical temperature.

No corals of any sort are known as yet in the Lower Triassic,
unywhere in the world, although the Hexacoralla must have
lived somewhere during that time, since they are known before
and after it. In the Middle Triassic of the Alpine province
reef-building corals occur, but are not abundant enough to
form reefs. They are not yet described from any other region.
Towards the end of the Upper Triassic reef-building corals
became abundant in the Alps, where they have long been
known, and where they formed genuine reefs that had an
important influence on the topography. There they extend up
to latitude 45° N., showing that in this epoch the Alpine
province enjoyed a warm climate. The chief coral zone of
the Alpine province occurs in the Noric epoch of the Upper
Triassic, not far above the rich ammonite limestone of the
Karnic epoch. The occurrence of this same coral fauna, in the
same stratigraphic position, in localities far removed from the
Meditermnean Region would be ample proof that the favor-
able conditions were widely distributed over the earth in this
epoch. This would also tend to show the probability of the
amelioration of the general temperature, at least over the
northern hemisphere, during this epoch.

Reef-building corals have been found in the Himalayas in
India in the Noric beds, but are not yet described ; their evi-
dence as to physical conditions is just as positive, even though
we do not yet know by what names they should be called.

In his studies of Triassic stratigraphy in northern California
the writer was long ago impressed by the fact that the lime-
stone there resembles coral rock, and fragments were found
that suggested remains of corals. Several years ago this was
confirmed by the discovery of abundant corals in many places
on the limestone ridge between Squaw Creek and Pitt Kiver,
and on Cow Creek south of Pitt River. The general section
of the Triassic of Shasta County is given below, to show the
position of the coral zone.

In the section given above, the thickness of the beds is only
approximate, varying from the maximum near the junction of

* Published with permission of the Director of the U. S. Geological Survey.

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in the Triassic of North America.


TVtaMie Section of Shasta County j California.


5 «


Black slates, with Piseiuiomonotis guheireularia.

Spiriferina beds, hard siliceous limestone, full of

Coral zone, with nnmerons reefs, of Astneidce,
l8€utr€Ba, Stepkanocoeniat Aatrocoenia^ Tkam-
nastroBa, and Theeosmilia,

Juvavitea beds, hard limestone, with abundant
ammonites, Juvavites, QonionotiteSf Disco-
phyllites, Tropites TeUeri, T. laestrigonus^

TrackyceroA beds, shaly limestone, with Trop-
ites ttubbullattiSf T. torquilltis, T. Dilleri,
Discotropites sandlingensia, Paratropites,
Traehyeeras Leeonteiy T. shastensSj etc.

Halobia superha shales, calcareous shales, full of
Halobia superba, and a few crushed Traehyeeras.

Halobia rugosa slates, black argillites, with Halo-
bia rugosa, and crushed Traehyeeras.

1800 ft.

100 ft.

50 ft.

50 ft.

100 ft.

1150 ft.

Unconformity !


Black siliceous shales, altered tuffs, and igneous
rocks, with Ceratites conf. humboldtensis.
PtychiteSj etc.

11500 ft.



NoBoni tnffs and shaly limestones, with Fusulina
eUmgata, etc.

McCloud limestone, with Fusulina robusta, F.
cylindrica, etc.

Squaw Creek and Pitt River, to less than half bo much on the
North Fork, 15 miles to the north, where the limestone
almost disappears entirely.

The Tropites auhbvUatus beds are divided into two zones, each
about fifty feet thick. In the lower are numerous Tropites
svbhullatus^ T torquillus, T Dilleri, T, Morloti^ T. fueo-
hvUatus^ Discotropites sandlingensis^ Traehyeeras Lecontei^
T. shastefhsCy Arcestes paci^ous^ ClioniteSy Halobia superha^
and many undescribed species of Tropites^ Tra^chyceras^ etc.

In the higher division, the Juvavites or Atractites beds are

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94 Smiih — The Occurrence of Coral Reefs

many, Juvavites suhinterrupttLS, J. subintermittensy J. Edgari^
Tropites laestrigonuSj T. TeUeri^ Homerites semiglobosusy
Discotropites 2%sron, D. Lawrae^ Pinacoceras rex^ Margor
rites senilis^ GonionoHtes^ Metasibirites, Choristoceras^ and
many other species, new and old, Tropites of the group of T.
TeUeri^ Discotropites^ of the group of T ZauraCj Atractites
and Dicl/yoconites.

A few feet above the highest Juvavites beds lies the coral
zone with reefs made up chiefly of Astraeidae^ Iso-straea pro-
ftmda, PhyUocoenia cf . decussata^ MonUvoa/uUia cf . Mojsvari^
TAecosmilta cf. fenestrata^ Stephanoooenia cf. Juvavica^
Thamnastraea cf . rectilamellosa ISpongiomorpha cL ramosa^

This coral zone was found from near Pitt Eiver, east of
DeLamar, northward to the North Fork, always in the same
horizon, between the Tropites limestones and the Pseudo-
monotis shales.

A few miles south of Pitt River, near the junction of Cedar
Creek with Little Cow Creek, the Hosselkas limestone out-
crops again, and the coral zone is here well developed. The
thickness is not so great as north of Pitt Biver, being reduced
to not much more than one hundred feet, the Tropites beds
having almost disappeared. Here the writer found in the
coral zone banks or reefs of Thecosmilia cf . fenestrata^ Isas-
i/raeaprofunda Reuss, Stephanocoenia ci.juvavieay Latimadan-
dra CT. eucystis^ and Thamnastraea cf . rectilamellosa.

At this localitv, as on Squaw Creek, the coral zone lies well
up in the Hosselkus limestone, and below the Pseudomonotis

In the Blue Mountains of northeastern Oregon, in Baker
County, at Martin's bridge, near the junction of Paddy Creek
with tagle River, the writer discovered in 1908 a small coral
reef in the Upper Triassic limestones, of which a section is
given below.

It will be noted that this section is entirely diflEerent, in the
lithologic sequence, from that of Shasta County, California.
Nothing lower than the Halohia shales was found, and the
writer could not determine just what part corresponded to the
Hosselkus limestone, since the Tropites beds were not exposed,
if they are present in that region. Nor could the Pseudo-
monotis shales be found above the coral zone, probably being
represented by the barren limestone. The lower shales, with
Malohia cf. superha^ were also found at the junction of the
two forks of Eagle River, at Anthony's hydraulic mine, but
there the limestones that should contain the coral reef are
crystalline, and the fossils destroyed. Massive limestone is
abundant on the North Fork of Eagle J4iver, but they are
everywhere changed to marble.

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in the Triassic of North America. 95

Section on Eagle River^ Baker County, Oregon.





ICaasiye limeetone without visible f oaails.

Dark brown argillaceous shales, with Halobia of. auetriaca,
and other species of Halobiay and Daonella f

Thin bedded limestone, with banks of corals, Theeoemilia
noriea Freeh, Spongiomorpfia cf . a4!ycliea Freeh, MonU
livaMia noriea Freeh, Hetercutridium conglohatum

Barren shales.

Massiye limestone without fossils.

Calcareous shales, with Halobia cf. tuperba, H, cf. scUina-
rum, H, cf . austriaea, Dittmarites sp. f etc.


100 ft.

40 ft.

800 ft.

100 ft.

80 ft.

Some years ago Mr. H. W. Turner discovered some corals
in limestone in T>unlop Canyon, Pilot Mountain, near Mina,
Esmeralda County, Nevada. These were sent to the writer,
who pronounced them Jurassic, as reported by J. E. Spurr*
upon this identification. A recent examination of these corals
has shown them to be more probably of Upper Triassic age,
which is in perfect accord witn the stratigraphy. The species
determined are : MontlivavUia cf. marmorea^ Astrocoenta cf .
Waltheriy and Pentacrinue sp. indet. The two species of
coral are well known forms in tne Noric beds of the Alps, and
Astrocoenta Waltheri occurs also in the Noric coral zone of
Shasta County, California. The Lower and Middle Jurassic
of the Great ISasin area are not known in the coral-reef facies

A few years ago Dr. G. C. Martin, of the U. S. Geological
Survey, discovered in the region of Cook's Inlet, Alaska, some
coral-bearing limestones. Among the specimens sent by Dr.
Martin from this locality the writer has determined : leastraea
cf . prqfimdaj Thecoemilia cf. fenestrata^ Phyllocoenia cf.
decussata^ P. cf. incrassata, Astrocoenta cf. Waltheri^ Mont-
livauUia cf. Mojevari^ and Spongiomorpha sp. indet.

This coral fauna is undoubtedly the same as that in the
lower Noric zone of Shasta County, California, and has several
species in common with that fauna.

This discovery of reef-building corals in Alaska extends
their range northward from 45° in the Alps, and in the Blue
Mountains of Oregon, to 60° N. Lat. The coral zone in Cali-
fornia, Oregon, Nevada, and Alaska belongs to the same hori-

♦BuU. 208, U. S. Geol. Survey, p. 102, 1908.

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96 Smith — JTie Occurrence of Coral Beef 9^ etc,

zon, and contains the fanna of the classic Zlarabach beds of
the Fischerwiese in the Tyrolian Alps, that is of the Noric
horizon of the Upper Triassic.

The group of Astraeidae is abundant in all these localities,
except in the Blue Mountains, and since they are still impor-
tant reef-builders, and now confined to the hottest parts of the
tropics, where the temperature does not fall below 74° F., it is
reasonable to suppose that in Triassic time they lived under
approximately the same conditions. This makes it probable,
if not certain, that the sea had a tropical temperature up to
60° N. Lat., at least in the Pacific Ocean.

Speculations as to ancient temperatures of the sea are inter-
esting, but of much more importance to geologists is the fact
that this Noric coral fauna gives us a new and distinct bench-
mark, which in its marked characters and wide distribution
equals that of the zone of Tropitea euhbidlcUus^ and enables
the positive correlation of strata that heretofore have been a
puzzle to stratigraphers.

Stanford Uniyersity, California.

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Dale — Ordovician OnUier at Hyde Ma/nor in Sudbury. 97

Art. XII. — The Ordovician Outlier at Hyde Manor in
Sudbury^ Vermont; by T. Nelson Dale *

In a paper on the geology of the north end of the Taconic
Rangef the writer called attention to the generally divergent
strikes of the Lower Cambrian and Ordovician in the town of
Sudbury, Vt., as a key to the perplexing geology of the western
side of the Taconic Range. These were regarded as pointing
to a crustal movement at the close of l-iower Cambnan time
which raised the Cambrian beds, west of the later formed axis
of the range, above water, and to their submergence in Ordo-
vician time, which was followed, at the close of Ordovician
time, by another movement which refolded the Cambrian beds
with the Ordovician, in places producing a folded overlap pos-
sibly accoinpanied by minor faulting. One of the pieces of
evidence offered was a small outlier of Ordovician limestone
in Avhat was then the golf course of Hyde Manor, about IJ
miles SSE. of Sudbury village and 6^ miles about WSW. of
Brandon, in Rutland (jounty, Vt.$

Dr. Rudolph Ruedemann, Assistant Paleontologist of New
York State, in a recent paper§ reproduced a part of the
writer's plate from this Journal and referred to the outlier in
these words:

"It is there quite probable that the whole folded plate of
Cambric rocks has been pushed along a slightly inclined fault
plane from the east over the Lower Siluric rocks, and that the
outlier of Stockbridge limestone does not rest in a small syn-
cline of the Cambric, as it would seem, but protrudes from
below the Cambric or is a " Fenster," as the European geolo-
gists term it (an outlier of younger rock protruding through
older rock in consequence of extensive overthrust and partial
weathering away of the overthrusted mass)."

In July and August, 1910, the writer spent a few days at
Hyde Manor in order to determine the real relations of the
outlier and with the aid of two men and dynamite four exca-
vations were made. The distances between outcrops and
excavations were measured with a steel tape. Thin sections
of the schist underlying the outlier on the north side and
overlying it on the east were examined microscopically to fix
the directions of bedding and cleavage. In May, 1911, the

• PnbUshed by permission of the Director of the U. S. Geol. Survey.

+ This Journal, Ser. 4, vol. xvii, pp. 185-190, pi. xi, 1904.

1 Ibid., p. 187, footnote, also p. 189, middle, pi. xi, black dot on section.

§ Rudolph Ruedemann: Types of inliers observed in New York, N. Y.
State Museum Bull. No. 188, 5th Rept. of the Director, 1908, Albany, 1909,
pp. 190, 191, fig. 88.

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98 Dale — Ordovieian Outlier at Hyde Manor in Sudbury.

Fio. 1.


. , *. * .\ ^T^**l Ft between: v'.;"^
. * limt^b.^ScKifCoutc







•O V
^ • /


•• *. o/


'0y -4-



5 10 ZO 30 40 50 Feet

T 1 CLEAVAGiE. , .





owjDov.LiHnr T ^ . i ^


V pT« O «OIY I I «• IMI <ll,UilJU<v'v^|l III

locality was a^aiii visited and in company with Messrs. Arthur
Keith, E. O. Ulrich, and C. W. Hayes of the U. S. Geol. Sur-
vey. More dynamiting was done at one old point and two

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DaU — Ordovidcm OutUer at Hyde Manor in Sudbury. 99

new ones. The Ordovician age of the outlier was definitely
established by the admission b;^ Mr. Ulrich of the finding of a
Streptelasma and crinoids in it on a previous visit. Knalljr
through the kindness of the late Mr. Fletcher Proctor, Presi-
dent of the Vermont Marble Co., the writer was also enabled
to have some core-diilling done, which was accomplished in
December 1911.

The results of all the excavations and of the core-drilling,
and the structure at the important outcrops, are shown on the

Fig. 2.




rs Inches ,


Tbt. 13 fV 6 iTi.





map (fig. 1) and also in the diagrams of fig. 2. The details are
given in the following paragraphs.

Eccavation 1 (fig. 2, A). — A trench was first dug from a large
outcrop of Cambiian schist east of the northeast comer of the
outlier, and a continuous exposure of the schist obtained to its
eastern edge on the north. Then blasting was resorted to. The
schist was found to overlie the limestone and to dip 35° E. The
limestone surface dips about the same, but at one point 45"^ E.
Further blasting to a depth of 5 ft. below rock surface reached a
small cave with water which stopped operations. The foliation
of the limestone here dips about 35 ** E.

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100 Dale — Ordovician Outlier at Hyde Mamyi* in Sudhv/ry.

Bxcavation 2 (fig. 2, B). — At the northern edge and near its
western side schist and limestone were found in contact along a
steep E.-W. line, but at a depth of 5 ft the schist was found to
underlie the limestone. Both rocks have a cleavage foliation
dipping 55^ roughly E. But that of the schist clips 8E. while its
bedding dips 75 ]N W. and the lower contact surface of the lime-
stone about 8° E. That this probably corresponds to bedding is
shown at a point east of one of the elms, where a small plicated
bed of dolomite in the limestone is about horizontal and its plica-
tions strike N. 16° W., which is one of the strikes typical of the
Ordovician in Sudbury. Near the elm this horizontal bedding
crosses a low easterly dipping cleavage, but on the east side of
the outlier the small dolomite beds dip east, about with the

MRcavation S. — Here a trench was dug 3 ft. deep through soil
to the schist and this was exposed by blasting to a depth of 14
inches. The schist foliation dips 40° eastward.

Mtcavation 6 (fig. 2, C). — A trench was dug from the Cam-
brian schist north or northeast of the northeast comer of outlier,
and the contact of schist and limestone was exposed by blasting.
Both rocks were found to be interfolded in a direction at right
to the strike but their relations deeper down were not determined.

Outcrops near elms (fig. 2, D).— These elms are on the west
side of the outlier. One is growing on it, and schist crops out
in contact with limestone and has a foliation dipping east under
it. South of the other elm the two rocks are within a few inches
of each other.

Excavations 4 and 5 (fig. 2, E). — Here a little trenching
exposed a surface of schist 10 ft. long doubled on itself and
embracing on the south a limestone, fold, 5 ft. thick at its widest
part. Two openings were made : one on the line of section
showed the limestone dipping about 46° E. between two schist
masses to a depth of at least 5 ft. The other exposed the apex
of the fold with an axial plane dipping 46° E. The bed surface
of the apex (not its solution surface) lies in a vertical E.-W.
plane and the schist surrounds the apex. The strike is N.20E.

Limestone ledge west of outlier, — ^This contains crinoids and
has a marked foliation dipping eastward and entered on map as
cleavage. The course of bedding is not clear.

Core-drill hole {fig. 2, F). — In May, 1911, one or two charges
of dynamite were put in at the point indicated on the map by a
star which is about 10 ft. NE. of the northern elm. The lime-
stone became exposed to a depth of 2 ft. 1 in. At this depth
Mr. Charles E. Connell, Supt. Brandon Marble Co., on Dec. 1,
191 1, had a core drill put in, using crushed steel for an abrasive.
After penetrating 5 inches of limestone the drill crossed 9 ft. of
soft rock, which it ground up mostly into sand. This effervesces
strongly with dilute HCl and under the microscope shows parti-
cles of calcite, quartz and schist. The magnet extracts consider-
able fine steel due to the abrasive. On Dec. 2 the drill struck

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Dale — Ordovician Outlier at Hyde Mano7* in Sudbury, 101

solid schist and went a foot into it. At the end of another foot
the core barrel became clogged and was left in the hole with its
core. As the limestone of the outlier contains some dark sericitio
streaks, the calcitic, quartzose sand with schist particles, brought
up by the drill, is evidently finely ground weathered limestone.
The cores obtained consist of 4*4 inches of limestone, and 4*5
inches of schist in 9 pieces. The pieces of schist all have a
marked easterly dipping cleavage and one piece, an inch thick,
has a quartz lamina crossing the cleavage. The diameter of this
core along the cleavage is 2^ by 2^ in.*

Conclv^(yn8, — The isolated mass of Ordovican limestone on
the old golf course of Hyde Manor in Sudbury, Vt, is sur-
rounded and underlain by schists of Lower Cambrian age upon
which it rests unconformably and with which it is interfolded in
synclinal attitude, and with which it is also interfolded on a part
of its northern side in a direction at right angles to the strike,
as shown in the section of fig. 1 and diagrams A-F and It
of fig. 2. This interfolding of the two formations reappears
40 ft. northwest of the outlier, where a small limestone fold
with an axial plane dipping 45° E. has a pitch lying in an
E.-W. vertical plane.

In view of the evidence, the application of the "Fenster"
theory of Alpine geologists to the relations in Sudbury as
shown in diagram G of fig. 2 is quite untenable. Valuable as
is the use of the imagination in geological investigations, geo-
logical science is still best advanced by careful observation and
induction. In this instance the induction has been verified by
physical demonstration through core-drilling.

The main mass of Ordovician limestone west of the outlier
is probably continuous with that interfolded with the Cam-
brian schists at excavations 4 and 5, and was, of course, once
continuous with the outlier or the beds adjacent to it. A little
north of the latitude of the outlier a well marked anticline
appears in the Ordovician limestone and the alternation of
tongues (synclines) of Hudson schist and of Ordovician limestone
shown on the map of the original article on this localityf
calls for such an anticline at that point, but the outlier is so
near a Hudson schist tongue on tne southwest that the anti-
cline can hardly be developed there nor is evidence of its pres-
ence obtainable. •

The general importance of the outlier is that it is as yet the
only point iu Western Vermont and Eastern New York where
the Ordovician can be seen unconformably on the Lower

* As qnestioiiB may arise as to this drining the names of the workmen are
given : Qeo. Mc Bride of Brandon and Dennis SnUivan of Sndbnry. Mr. C. E.
Connell of Brandon was also present when the solid slate was stmck at depth
of 11 ft. 6 in. from surface.

fThis Jonmal, vol. xvii, pi. xi, 1904.

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102 Dale— Ordovician Outlier at Hyde Manor in Sudhury.

Cambrian, the refolding of these fonnations at the close of
Ordovician time having in other places obscured any original
divergence in their strike. As on the eastern side of the Cam-
brian belt, 2 miles nearly ENE. of the outlier, Cambrian and
Ordovician are also in marked unconformity, a westward thrust
of the Cambrian on the west side is not consistent with an
eastward thrust of it on the east side, which the proposed
"Fenster" theory would involve. Minor faulting may well
have occurred on both sides in the refolding of two unconform-
able formations, but it was a secondary element. The prime
factors in the relations of the two formations are : a crustal
movement at the close of Lower Cambrian; emergence and
erosion of the Cambrian beds, followed by their submerg-
ence and the transgression of the Ordovician, and finally
another crustal movement, but at a slightly different angle
from the earlier one, which refolded both formations.

The little outlier is a structural specimen, still in situ and
small indeed, but preserving the record of one transgression,
two crustal movements, and two periods of erosion which
affected several hundred square miles of the Taconic region.

Pittsfield, Mass.,

Dec. 16, 1911.

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H, Z. WdU — GoZar-Effect of IsomorpJioue Mixture, 103

Art. XIII. — On a Color-Effect of horrwrphouB Mixture ; by
Horace L. Wells.

It appears to be a general rule that crystals composed of iso-
morphous substances, in case either or each of these is colored,
assume a color intermediate between the colors of the com-
ponents, and so far as the writer is aware, no unexpected
colors have, been observed in such mixtures. For instance, it
was found in this laboratory several years a^o* that the yellow
salt OSjPbCle and the deep blue salt Cs,8bCl, gave green mix-
tures, as would be expected.

I have recently observed a curious color-effect when the
Cs,PbCl„t which was mentioned above, crystallizes with
CSjTeCl,.:^ Both of these salts form bright yellow crys-
talline precipitates. The lead compound has the color of sul-
phur, while the tellurium compound has a slightly brighter
tint, but their colors are so nearly alike that they can hardly be
distinguished without direct comparison. Both of the salts
crystallize in isometric octahedra, like K,Pt01, and many other
compounds of the same type.

These two yellow salts of lead and tellurium are sparingly
soluble in hydrochloric acid, and, therefore, are easily prepared.
When the conditions are such that both are deposited at the
same time from a solution, the product always has a bright

Online LibraryJohn Elihu HallThe American journal of science → online text (page 10 of 61)