(Lancian)
fromtheMcRae
LateCretaceous
dinosaurs
Formation,
NewMexico
Sierra
County,
Resources,
byRichard
P.Lozinsky,
Adrian
P.Hunt,andDonald
L. Wolberg,
NewMexico
Bureau
of MinesandMineral
Albuquerque,
NM
Socorro,
NM,andSpencer
G Lucas,
University
of NewMexico,
Introduction
Identifiable skeletal elements of Late Cretaceous dinosaurs are known from three formations in New Mexico: the Fruitland
Formation and Kirtland Shale of the SanJuan
Basin, and the McRae Formation in and
around the Elephant Butte Reservoir area.
This is the second published description of
dinosaur remains from the McRae Formation. The first report was published by Lee
(1905). Recent discoveries of McRae dinosaurs began in 1981when Lozinsky observed
the presence of dinosaur-bone fragments
duriig geologic studies in the Elepharit Butte
area (Lozinsky, f982). Subsequent fossil
prospectinghas yieldedadditional dinosaurbearing localities (Fig. 1). In this paper we
describethe dinosaurand fossil-plantoccurrences,we review previous studies of the
McRaeFormation,and we discussthe age of
the McRae and its oossible correlation to
stratigraphicunits in the WesternInterior.
McRae Formation
Although recognizedas a discrete stratigraphic unit since the early twentieth cent u r y ( e . g . , L e e , 1 9 0 5 , 1 . 9 0 7 ) t, h e M c R a e
Formation was first named by Kelley and
Silver (1952).This unit consistsof a thick sequenceof nonmarine clastic rocks exposed
in the Cutter sag and Jornada del Muerto
(Fig.2). Bushnell(1953,1955)recognizedtwo
McRaemembers, the lower JoseCreek and
the upper Hall Lake, and he suggestedthat
the McRaeFormationmay approach1,000m
in thickness(Fig.3). Becausepart of the section is submergedbeneath the waters of Ele o h a n t B u t t e R e s e r v o i r a n d b e c a u s eo f
pronounced faulting, measurement of a
completesectionis not possible.
The fose Creek Member restsunconformablv uoon rocksof the MesaverdeGroup and
consisisof a sequenceof sandstone,shale,
conglomerate,and an unusual brecciaconglomerate (Bushnell, 1953;Lozinsky, 1982,
1984).This member is 120m thick at its type
locality.
The Hall Lake Member conformablyoverlies the JoseCreek and is distinguished by
its abundanceof purple and maroon shales.
The boundary between the two membersis
marked by a basal conglomerate.When the
conglomerate is absent, the boundary is
marked by the first purple or maroon shale.
The top of the Hall Lake Member is absent
in all areasand is unconformablyoverlainby
variousCenozoicunits.
Paleobotany
Megascopicplant remainsappearto be restricted to the Jose Creek Member and are
most common in the finer grained sandstonesand siltstones.Fossilleavesalso have
been reported from the underlying upper
CrevasseCanyon Formation (Table 1; Lozinsky, 1982;Wallin, 1983).Despite difficulties
that arise from comparing CrevasseCanyon
and fose Creek fossil floras to floras elsewhere, the assignmentof a Late Cretaceous
age to the CrevasseCanyon and McRae is
consistentwith available data as indicated
below.
In addition to fossil leaves,abundant petrified wood fragments and occasionalfragmentary logs and in situ stumps occur in the
JoseCreek Member. Some of the stumps are
of substantialsize ( t 1 m in diameter)and
appearto be in growth position.
FIGURE 1-Generalized geologic map of the Elephant Butte Reservoir area; dinosaur-bearing localities
are highlighted in blue.
November
1984
Nm Mexico Geology
Vertebratepaleontology
Lee (1905)reported dinosaur bonesin rocks
at or near Elephant Butte. Two additional
collectionswere made in the areaduring the
next eight years (Kelley and Silver, 1952),
and these fossils were referred to the ceratopsian genusTricuatopsby I . W. Gidley (Lee,
1907;LulI,1933).The fossilmaterialcollected
during the 1905-1913period was included
in the collectionsof the U.S. National Museum. Today, this material consists of two
dinosaur vertebral centra and other bone
-
o
_c.
C)
3
()
o
.9
a
FIGURE4-Anterior viewsof USNM2437(x tlz\,
possiblyby
dorsalcentrareferredto Triceratops,
J. W. Gidley (Lee,1907;Lull, 1933;bar is 10 cm
long).
t-
S\8
6ptslr'7:\+\
i*l
',
/
s\
\te\
o
o
25mi
25km
FIGURE 2-Tectonic setting of the Elephant Butte area. Hatched lines are normal faults with hatchures
on the downthrown side; the lines are dashed where faults are buried or inferred. Solid lines delineate
major uplifts (after Woodward and others, 1978).Shaded portion is the area coveredby Lozinsky (1982,
1984).
TABLE 1-CnEvessl CaNvoNeNo Iosr Cntlr ruones
(r
F
E,
lrl
F
TOP ERODEDAND NOT
S E E N ,O V E R L A I NB Y
QUATERNARY-TERTIARY
BASALTFLOWSAND
ALLUVIUM
ro
tr)
o,
HALL LAKE
Rock unit
JoseCreek Member
of McRae
Formation
(Bushnell, 1953;
Kottlowski, et al.,
1956;Lozinsky,
1982)
Geinitziacf. formosa
?Cannamagnifolia
Sabalmontana
Plryllitescf. ratonensis
Salixsp.
sp.
Cinnamomum
Sequoia
sp.
Seauoiareichenbach:
Sabatitessp.
Sabalites
montana
Ficusplanicostata
Ficustrinerius
Viburnummarginatum
Araucarit es longifolia
CrevasseCanyon
Formation
(Lozinsky, 1982;
Wallin, 1983)
Sequoiamontana
Ficusolaniostata
cf . Dryophyllum sp.
cf . Inurophyllum wardiana
cf . Dillenitescleburn:
Cercidiphyllumsp.
cf. Quercusaiburnit'olia
-zJSBEf-r'(-884m)
'
(D
C
E
o
a
l
o
lrJ
o
F
UJ
E.
()
rO
@
i
3
ASH CANYON
( 2 4 Om )
MEMBER
B A R R E NM E M B E R
( 328 m)
Taxa
fragments,all cataloguedas USNM 2437.lt
is likely that these specimensare all that remain of the 1905-1913collections.Figure 4
shows the two centra that have been referred
FIGURE 3-Generalized stratigraphic column for to Triceratops.
Current criteriafor defining ceratopsiantaxa
the Elephant Butte area based on Lozinsky (1982,
1984)and Wallin (1983).
are basedmainly on skull characteristics.The
COAL-BEARING
( 1 3 7m )
MEMBER
USNM 2437 collection contains no cranial
material and cannot provide a realistic basis
for generic identification. However, the two
centra of USNM 2437 are large and within
the size range of Triceratops(Hatcher and
a Late Creothers, 1907, pl.8). Torosaurus,
is
taceousceratopsianas large as Triceratops,
known only from cranial remains (Colbert
and Bump, 1947).It is not possibleto determine whether USNM 2437rcpresentskiceror a new ceratoPsiantaxon.
ntops,Tbrosaurus,
Between1913and 1981no dinosaur fossils
were collected from the McRae Formation,
although no less than seven geologic mapping projects included the McRae (Doyle,
1951;Kelley and Silver,1952;Bushnell,1953;
McCleary,'1960;Thompson, 1951; Melvin,
1.963;Warren, 1978).However, in 1968,John
Hawley and William Seager(now at the New
Mexico Bureau of Mines and Mineral Resources and New Mexico State University,
respectively) were notified of a partial ceratopsianskull discoveredat a time of a very
low water level in the Elephant Butte Reservoir. Unfortunately, this locality has not
been exposedsince then.
The studies initiated bv Lozinskv in 1981
haveresultedin the discoveryof l2"localities
(Fig. 1) that have yielded fossil matedal representingfour dinosaurtaxa(anotherlocality
lies just outside the map area to the north).
Additionally, in 1983 a yachtsman discovered a locality on the east bank of the reservoir that yielded an incomplete jaw of
rex. This very significant specTyrannosaurus
imen is in the collections of the New Mexico
Museum of Natural History and has been
made availableto us through the courtesy of
David Gillette, who first recognized its significance.A detaileddescriptionof this specimen will be undertaken by the New Mexico
Museum of Natural History and the New
Mexico Bureau of Mines and Mineral Resourcesin a separatepaper.
THE USNM fossilsprobably camefrom low
in the Hall Lake Member. Localities discovered recently occur at or near the boundary
between the Hall Lake and JoseCreek Members.Fossilboneis often associatedwith conglomeraticor shaly beds. Discussionof the
most significant specimens found by us follows.
New Mexico Geolo3y November 1984
FIGURE5-TKM001, dorsal theropod centrum: (A) anterior,(B) lateral,and (C) dorsalviews; TKM007,Alamosaurus
sp. humerus:
(D) anterior and (E) posterior views; TKM002, ceratopsiancoronoid process:(F-G) lateral views; TKM020, ceratbpsiancrest
(H)
(I)
fragment:
dorsal and
ventral views; TKM01l, ankylosaurarmor fragment:(f-K) lateraland (L) basalviews. The solid bars
are all 5 cm in Iength exceptD-E, which is 10 cm.
November7984 NewMexicoGeology
Centrum
TKM001(Fig.5, A-C) is an incomplete,but
relativelywell preserved,dorsal centrum. It
is strongly opisthocoelousand ovoid in out-
preserved anteroventrally, but it is likelv to
have been similarly devetopedand to have
{ormed a deep concavity between the two
lipJike structures.
The strongly opisthocoelouscharacter,relatively large size, presence of a pleurocoel
and secondaryforamina on the pedicelsof
the neura! arch, and the excavaiednature
betweenanterior and posterioroverhanging FIGURE6-Sauropod femur (TKM009), still partially encasedin sandstone of the fose Creek Member
lips lead us to believe that TKM001 re-prel matrix,is more than 168cm long.
sentsa large theropod, possibly a tyrannostill partially encasedin matrix, extendsdiCeratopsian crest fragment
saurid.
TKM020 (Fig. 5, H-I) is a bone fragment
125mm x 115 mm that varies in thickness
Humerus
from 34 mm at its broken edge to 8 mm at
an almost intact margin. The cortex is cancellous and bounded above and below by
dense, laminar bone. The surfaces of th-e
representsa sauropod.The most reasonable
fragment are slightly concave and slightly
hypothesisis that this specimenbe referred
convex, respectively. Both surfaces exhibit
to Alamosaurus.
However, there is a strong narrow linear and arcuate
grooves, interat the humeral head and extends in an arc tendencyto refer recordsof Late Cretaceoui
preted as impressionsof blood vessels.Based
North American sauropods to Alamosaurus
on these features and comparison with mawithout real justification. Apart from the
terial availableto us, TK1vi020representsa
forelimb described by Gilmoie (1946), little
fragment from a ceratopsiancrest. Given the
is known of the apendicularskeletonof Alathickness of this fragment it is likely that it
camefrom a large individual.
sanjuanensis,known from the Naashoibito
Member of the Kirtland Shalein the SanTuan
Basin (Gilmore, 1922),the Javelina Formation of Texas(Lawson, 1976),and the lower
part of the North Horn Formation of Utah
(Gilmore, 1945).The deltopectoralcrest of
TKM007 is less massivethan that of Alamosaurusand is not as medially deflected.However, Gilmore (1946)notes-thatthe extent of
the medial deflectionseenin the North Horn
specimen has been exaggeratedby lateral
crushing. .This specimen-is tentatively referred to Alamosaurus
sp.
Ceratopsiancoronoid
summit is rugose and the anterior coronoid
margin curves up and forward into an anteriorly_directed, hook-like process.A deep
cavity for the reception of the surangular is
presentat the posteriorof the coronoid.These
Femur
featuresare sufficientto demonstratethe cerTKM009 is a massiveleft sauropod femur atopsian nature of TKM002. Although it is
(Fig 0) that is at least 168 cm long and 46 not possible to differentiate between Tricercm wide proximally. The specimenwas found atops and Torosaurusbased on the material
in a thoroughly silicified pebbleconglomer- available,the coronoid is much more masate and is still in the field.
sive and not as high as the coronoid in PenThe shaft is straight and the proximal head, taceratoos.
Ankylosaur armor
TKM011 is a pyramidal, laterally compressed bone fragment 75 mm long, 45 mm
wide, and approximately 70 mm high (Fig.
5, J-L). A central and roughly circular medial
foramen is present in its base.
This specimen,although poorly preserved,almost certainly is a fragment of ankylosaur armor, more specifically a
compressedconicalplate (Co6mbs,nZAl. n
is virtually identical to an ankylosaur plate
in the University of New Mexico collections
(UNM-FKK-001P) from the Lancian Naashoibito Member of the Kirtland Shale.
Our current interpretation of the composition of the McRae fauna is shown in Table
2.
Age of the McRae Formation
Controversyand misconceptionhave surrounded the question of the age of the McRae
Formation and of its relationships to other
formations in the Western Interior. Table 3
summarizesthe changing concepts.
re
NewMexicoGeology November 1984
TABLE 2-CovposrrroN oF THEMCRAEFAUNA
the only means for narrowing the minimum
age for the McRae Formation. The presence
Class Reptilia
of Tyrannosaurusrex (the NMMNH speciSubclassArchosauria
men), a large theropod (possibly a tyrannoOrder Saurischia
saurid), severallarge ceratopsianspecimens
Suborder Theropoda
(early reports, the Hawley skull, our collecInfraorder Cainosauria (TKM001)
tions), and a titanosaurid referred by us to
Familv Tvrannosauridae
Alamosaurusis strongly, if not conclusively,
Tyrinnosaurusrer (New Mexico
in favor of a Lancian age for the McRae ForMuseum of Natural History jaw)
mation.
Infraorder Sauropoda (TKM009)
The Lanciandinosaur fauna from the North
Family Titanosauridae
Horn Formationdescribedby Gilmore (1946)
G enus Al amosnurus (TKJ|/1007\
contains Tbrosaurus,Alamosaurus,and TyrOrder Ornithischia
annosaurus(Lawson, 7976).The Naashoibito
Suborder Ankylosauria (TKM011)
Member of the Kirtland Shalealso contains
Suborder Ceratopsia
these three genera (Gilmore, 1922;Lehman,
Family Ceratopsidae(USNM 2437,
L981;Lucas et al. (pers. comm. 1983).AlTKM002, TKM020, Hawley
though Lancian in age, these faunas do not
specimen)
contain Triceratops.
As we have shown, it is
C R E T A C E O UDSI N O S A U R
not possibleto determine whether the McRae
FAUNAS
The youngest diagnostic fossil that occurs ceratopsianis Triceratops
or Torosaurus.
below the McRaeis Lophasannionis,found in
Sloan(1970)proposedthe conceptof a biothe Gallup Sandstone (Wallin, t983). L. san- geographical dichotomy of Maestrichtian FIGURE7-Geographicdistributionof the latest
dinosaurcommunitiesin North Amernionis ranges from late Turonian to early terrestrial communities in the Western In- Cretaceous
Coniacian(Hook and Cobban, 1981).How- terior of North America. The "Triceratops ica(afterSloan,1970).
ever, the Gallup strata are separatedfrom the community" of Sloanwas dominatedby TriMcRaeby at least 700m of intervening strata ceratops,Anatosaurus,Torosaurus,and Tvranof the CrevasseCanyon Formation (Wallin, nosaurus.This community extended as far ence of the Alamosaulrs community in the
1983).In the San fuan Basin, the Crevasse south as north-central Colorado (Fig. 7). A McRae leads to the conclusion that at least
Canyon contains early Coniacian pollen southern "Alamosauruscommunity" was the upper part of the JoseCreekMember and
(Tschudy,t976) and may extend up to the characterizedby the presenceof Alamosaurus the lower portion of the Hall Lake Member
Lancian in age. Becauseapproximately
mid-Santonian(Molenaar,1983).Marine de- andTbrosaurus
in addition to the persistence are
m of the Hall Lake Member overlies the
850
p o s i t s a s s o c i a t e dw i t h M o l e n a a r ' s T - 4 of more archaic hadrosaurs (Sloan, 1970).
transgression terminated Crevasse Canyon Basedon recent discoveries,it now appears dinosaur-bearingrocks, it seemsreasonable
to infer that the upper portion of the Hall
deposition in the San |uan Basin, but this that the Tyrannosaurus
is present in the AIaLake Member is at least early Paleocenein
transgression did not reach Sierra County, mosaurus
community as well.
a8e.
New Mexico (Molenaar,1,983,fig.2). ThereThe presence of the AlamosauruscommuBased on extant collections, the presence
fore, no upper age limit can be placedon the nity in ihe McRaeFormation of south-central
in the McRae Formation cannot
of
Triceratops
CrevasseCanyon Formationin the Elephant New Mexico ties together the other reported
Butteareabasedon regionalcorrelations.An occurrencesof this community: the Javelina be demonstrated, and we cannot exclude the
age substantiallyyounger than mid-Santon- Formation of west Texas, the Naashoibito possibility that the ceratopsianpresent is Torosaurus.Indeed, given the known distriian is quite possible.
Formation of the San |uan Basin, and the
At present,paleontologicalevidenceoffers North Horn Formation of Utah. The pres- bution of these ceratopsiansand Sloan's
community concept, it is more likely that Torosaurusis the ceratopsian present in the
TABLE 3-Svr.ropsls oF CHANGINGcoNcEprs oF THE AGE or rnr McR-lr FonveloN.
McRae.If future collecting demonstratesthat
Triceratopsis present in the McRae, Sloan's
community concept would have to be modUPPERCRETACEOUS
ified, but the probable age relationships of
the McRae to other stratigraphic units would
remain unchanged. Fig. 8 shows our proWILPOLTAND
posed correlation with units elsewhere.
(I95I)
WANEK
authors wish to
ACKNOWLEDGMENTS-The
thank Mr. and Mrs. Ival Kennedy and Mr.
S I L V E R( I 9 5 5
and Mrs. EarleGeorge,ElephantButte, New
Mexico, for their courtesy and kindness; we
B U S H N E L L( 1 9 5 3 )
thank TennecoOil Company for accessto the
PedroArmendaris Land Grant, the U.S. Bu(I953)
KOTTLOWSKI
reau of Reclamation for accessto Elephant
Butte Reservoir,Coleman Robison, Getty Oil
S I L V E R( I 9 5 5 )
Company, for identifications of paleobotanmaterial, David Gillette, New Mexico
ical
KOTTLOWSKI
Museum of Natural History, for the loan of
Er AL.(t956)
rex iaw, and Nichothe McRae Tyrannosaurus
KOTTLOWSKI
AND
las Hotton III for accessto the U.S. National
B U S H N E L(LI 9 5 4 )
Museum collections from the McRae.
This manuscript was read by David Berman, Carnegie Museum of Nafural History,
LUCASAND
and firi Zidek, New Mexico Bureau of Mines
I N G E R S O(LIL9 8 I )
and Mineral Resources.We appreciate their
helpful suggestions. Drafting for this paper
was done by Teresa Mueller. The research
November 19M New Mexico Geology
reported in this paper was supported by the
New Mexico Bureau of Mines and Mineral
Resources,Frank E. Kottlowski, Director.
References
Bushnell,H. P, 1953,Geologyof the McRaeCanyonarea,
Siena County, New Mexico:UnpublishedM.S. thesis,
University of New Mexico, 105 pp
-,1955,
Stratigraphyof the McRaeFormation:Compass,v.33, pp 9-17
Colbert,E H, and Bump, J ,1947, AsktllofTorosaurus
from South Dakota and a revision of the genus: Proceedingsof the Academy of the Natural Sciencesof
Philadelphia, v 99, pp. 93-106
Coombs, E P.,lr , 1978,The families of the ornithischian
dinosaur order Ankylosauria: Paleontology,v 21,,pp
1.43-170.
Doyle, J C , 1951,Geology of the northern CaballoMountains, Siena County, New Mexico: Unpublished M.S.
thesis, New Mexico Institute of Minine and Technology,5l pp
Gilmore,C.W ,7922,A new sauropoddinosaurfrom the
Ojo Alamo Formation of New Merico: Smithsonian
MiscellaneousCollections,v.72, no. 14,9 pp.
-,
1946,Reptilian fauna of the North Horn Formation of cenhal Utah: U S. Geological Survey, Professional Paper 210, pt. C, pp.29-53.
Hook, S C , and Cobban, W. A , 1981,LophaSannioniscommon Upper Cretaceousguide fossil in New Mexico:
New Mexico Bureau of Mines and Mineral Resources,
A_nnualReport, July 1.,1979to June 30, 1980,pp 52JO.
Kelley,V. C., and Silver,C.,1952,Geologyof the Caballo
Mountains, with special reference to regional stratigraphy and structure and to mineral resources:University of New Mexico, Publicationsin Geology,no 4,286
PP
Kottlowski, F. E., 1953, Tertiary-Quaternary sediments
of the Rio Grande Valley.insouthern New Mexico: New
Mexico GeologicalSociety,Guidebook to 4th Field Conterence,pp 7M-1,48.
Kottlowski, F E , and Bushnell, H P., 1954,Late Creraceousand early Tertiary outaops of Jomadadel Muerto,
New Mexico Geological Society of America, Bulletin,
v 67,p 768
Kottlowski, F. E., Flower, R. H., Thompson,M. L., and
Foster,R. W., 1956,Shatigraphicstudies of the San
Andres Mountains: New Mexico Bureau of Mines and
Mineral Resources,Memoir 7, 132pp.
Lawson, D., 7976,Tyrannosaurus
and'Torosaurus,
Maashichtian dinosaurs from Trans-PecosTexas:Journal of
Paleontology,
v.50, pp. 158-154
Lee, W T., 1905,The Englecoalfield, New Mexico:U.S
GeologicalSurvey,Bulletin 285,240pp.
-,
1907, Notes on the red beds of the Rio Grande
region in central New Mexico: Journal of Geology, v
ls, pp 52-s8.
Lehman, T., 1981,The Alamo Wash local fauna: A new
look at the old Ojo Alamo fauna; in Lucas, S G , et al
(eds.), Advances in San Juan Basin Paleontology,pp.
789-221.
Lozinsky,.R.?., 1982,Geologyand late Cenozoichistory
of the Elephant Butte area, SierraCounty, New Mexico:
lr,
lrJ
(J
o
lrJ
J
f,
F
lrJ
E,
()
1984, Geology and late Cenozoic history of the
Elephant Butte area, Siena County, New Mexico: New
Mexico Bureau of Mines and Mineral Resources,Circular 187,40 pp
Lucas,S G, and Ingersoll,R V, 1981,Cenozoiccontinental deposits of New Mexico-an overview: Geological Society of America, Bulletin, v 92, pp 917-932
Lull, R S , 1933,A revision of the Ceratopsiaor horned
dinosaurs:Memoirsof the PeabodvMusium of Natural
H i s t o r y ,v . I I I , p t 3 . 1 7 5p p
McCleary, I T , 7960,Geology of the northern part of the
Fra Cristobal Range,Siena and Socono Counties, New
Mexico:Unpublished M S thesis,University of New
Mexico,59 pp,
Melvin, J W., 1963, Cretaceousstratigraphy of the Jornada del Muerto region including the geology of the
Mescal Creek area: Unpublished M S thesis, University of New Mexico, 121pp.
Molenaal C. M., 1983,Major depositionalcyclesand regional conelationsof Upper Cretaceousrocks, southern ColoradoPlateauand adiacentarea; ln Mesozoic
paleogeographyof the west-centralUnited States:Rocky
Mountain Section, Societyof Economic Paleontologists
and Mineralogisls, pp. 201-224.
Seager,W R , 1981,Geologyof the Organ Mountainsand
southern San Andres Mountains, New Mexico: New
Mexico Bureau of Mines and Mineral Resources,Memo i r 3 5 , 9 7p p
Silver, C , 1955,Geology of ihe Caballo Mountains: New
Mexico GeologicalSociery guidebook to 5th Field Conference,pp 146-154
Sloan, R E , 1970,Cretaceousand Paleoceneterrestrial
communitiesof western North America: Proceedinqs
of the North American PaleontologyConvention, p1.
E, pp. 427-453.
Thompson,S., ill, 1,961,
Geologyof the southernpart of
the Fra Cristobal Range, Sierra County, New Mexico:
UnpublishedM.S thesis(revised),University of New
Mexico, 75 pp.
Tschudy,R, 1,976,Palynologyof CrevasseCanyon and
Menefee Formation of San Juan Basin, New Mexico:
New Mexico Bureauof Mines and Mineral Resources,
Circular 154, pp 48-55
Van Valen,L.,7969,What was the largestdinosaur:Copeia, no. 3, pp.624-626.
Wallin, E. T., 1983,Stratigraphyand paleoenvironments
of the Engle coal fieldl Sierra County, New Mexico:
UnpublishedM.S. thesis,New MexicoInstituteof Mining and Technology,1,27pp
Wanen, R C , 1978,Characterizationof the lower crustupper mantle of the Engle Basin, Rio Grande rift, from
a petrochemical and field study of basalts and their
inclusions:Unpublished M S. thesis,University of New
Mexico, 155pp.
Wilpolt, R. M., and Wanek,A. A., 1951,Geologyof the
region from Socorro and San Antonio east to Chupadera Mesa, Socono County, New Mexico: U.S. GbologicalSurvey,Oil and Cas Investigations,OM-121.
Woodward,L. A , Callender,J. F., Seager,W R., Gries,
, L , a n d Z i l i n s k i ,R E , l g 7 \ , T e c t o n i c
J . C , S h a f f e rW
map of the Rio Grande rift region in New Mexico, Chi
huahua,and Texas;in Hawley,J. W. (compiler),Guidebook to the Rio Granderilt in New Mexicoand Colorado:
New Mexico Bureauof Mines and Mineral Resources,
Circular163,sheet2, scale1:1,000,000
tr
S A NJ U A N ELEPHANTB I G B E N D
MONTANA
BASIN
BUTTE
TEXAS
UTAH
z
UnpublishedM S thesis,Universityof New Mexico,
742pp
-,
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NORTH
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HORN
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BLACK
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FIGURE8-Proposed correlationof the McRaeFormationwith rocks found elsewherein the Western
Interior.
NewMexico
Geology
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duesto $10andstudentmemberdues
to $6beginningin 1985and to provide
memberswith a subscriptionto Nera
MexboGeology
at no additionalcost.
The executivecommitteedecidedto
begin charging1985ratesfor duesat
the 1984fall field conferenceand to
considerthosewho ioin at the conferencemembersfor both 1984and 1985.
Therefore,you can obtain your 1985
subscription to Neut Mexico Geologyby
enclosing$6.00,the regularsubscription
price, in the renewal envelope or enclose $10 to ioin (or continue membership in) NewMexico GeologicalSociety.
If you already paid NMGS dues at the
fall field conference(October 12-15,l9U,
in Taos)or if you paid your dues since
then, you will receive Neut Mexico Geolo8y automatically for the calendar year
1985.
Nau MexicoGeology November 1984
77