l 9(P<3 KCIfiZ A. LOWEHSTAI PERMIAN CORALS FROM NEVADA AND CALIFORNIA 1 i W. II. EASTON ! Reprinted from JOURNAL OF PALEONTOLOGY Vol. 34, No. 3, May, 1960 JOURNAL OF PALEONTOLOGY, V. 34, NO. 3, p. 570-583, 18 TEXT-FIGS., May, 1960 PERMIAN CORALS FROM NEVADA AND CALIFORNIA W. H. EASTON University of Southern California, Los Angeles 7, California ABSTRACT—Seven species of rugose corals are described from Permian (mostly Leonard Series) strata in the Basin and Range Province of Nevada and California. Caninia trojana, Lithostrotionella mokomokensis, Lithostrotionella dilatata, Diphy- phyllum connorsensis, Thysanophyllum princeps, Lonsdaleia illipahensis, and Lonsdaleia cordillerensis are named. The corals occur in thick successions of com- monly cyclical alternations of limestone and sandstone near the eastern margin of the Cordilleran geosyncline. Local distribution and biostromal development can be used in subdividing and mapping the Permian strata of east-central Nevada. INTRODUCTION along the eastern or continental side of the Cordilleran geosyncline. HICK deposits of marine strata of TPermian age crop out in the Basin and It has been the good fortune of the Range Province in California, Nevada, and writer to be able to study and to collect Utah. Although paleontologists have de- from numerous successions of Permian voted some attention to the fusulinids in strata in the Cordilleran region. This work these Permian beds, much more descriptive was begun in 1947 and has continued work is needed on all phases of paleontology. through most of the succeeding summers. The purposes of this paper are to describe During parts of five summers the writer was some species of corals from the area and to engaged in mapping with students enrolled show their stratigraphic occurrence in the in the summer field geology courses con- Permian System. ducted by the University of Southern Cali- Permian corals have been discovered in- fornia in White Pine County, Nevada. Sev- frequently in North America, partly be- eral summers were spent in paleontologic cause of the restricted nature of Permian and stratigraphic studies of Permian and seas and partly because of seemingly ad- other strata on other projects. It is a pleas- verse environments for growth of corals in ure to acknowledge my indebtedness to nu- those seas. Known Permian faunas include merous students, faculty colleagues, and to several corals which have been described various other geologists for assistance in the from the midcontinent by Moore & Jeffords field work. Collections described herein (1941), who also (1941, p. 67,68) review which were originally made in the course of the previous works in that area. Permian field investigations for Union Oil Company corals from British Columbia have been de- of California have been deposited at the scribed by Smith (1935); from Oregon, by University of Southern California through Merriam (1942); and from California, by the kindness of Dr. J. C. Hazzard. Langenheim & McCutcheon (1959). Corals are locally very abundant in STRATIGRAPHY Permian strata of the Basin and Range Corals are described from two Permian Province. Indeed, they may comprise bio- localities in the southern part of the Basin stromes a foot or more in thickness. More- and Range Province. The detailed strati- over, some species are widespread, ranging graphic succession of Permian rocks in the north-south over a distance of at least 500 Providence Mountains of southeastern miles from northeastern Nevada to south- California has been published by Thompson eastern California. It is probable that the & Hazzard (1946), and the general se- corals occupy an east-west zone at least quence of Permian strata in the Spring 200 miles wide in the region between the Mountains of southwestern Nevada has Confusion Range of west-central Utah and been discussed by Longwell & Dunbar the Eureka district of east-central Nevada. (1936). Thus, a coralline facies of the marine Per- Only part of the thick Permian succession mian strata seems to have been deposited in east-central Nevada has been published 570 PERMIAN CORALS FROM NEVADA AND CALIFORNIA 571 in detail. Knight (1956) has published graphic sections of two stratigraphic suc- KAIBAB" LS. cessions of Leonard strata in White Pine County. Additional detailed measurements are available for somewhat lower strata in 3 the same county through unpublished re- search by Ehring (1957). Most of the corals 5000 to which reference is made herein were col- lected from Permian strata in White Pine County. The Permian succession in east-central Nevada is one of the thickest discovered in North America. It is possible that over 7000 feet of Permian strata are represented there, of which at least 5000 feet are refer- 4000 - 1—~t able to latest Wolfcamp and Leonard Epochs. Corals have not been discovered in the latest Leonard or in the Guadalupe strata in the areas studied. The Permian succession pertinent to this report is depicted schematically in text- figure 1. Thicknesses are only approximated because the section is a composite of out- crops at several localities. The region is one 3000 - of considerable structural complexity, in addition to which the western outcrops in the region represent a more carbonate-rich l_L_ facies than is present in the eastern out- crops. Solution of some perplexing struc- tural and stratigraphic problems has been materially assisted by use of corals in a block of quadrangles consisting of the Ely, 2000- Illipah, Illipah 1 advance sheet, Treasure Hill, Pancake Summit, Green Springs, and Buck Mountain quadrangles. The most nearly complete and readily accessible locality in which the Late Paleozoic rocks can be studied in the area lies along U. S. Highway 50 in the east half — ZONE 2 of the Illipah quadrangle, about 30 miles (airline) west of Ely, Nevada. The Illipah 1000 - section has been studied by many geol- ogists engaged in exploratory programs of oil companies in Nevada between 1948 and the present. The section lies within the re- gion mapped during several summers by students at the summer field geology camp of the University of Southern California. — ZONE 1 0 -J TEXT-FIG. 1—Schematic and composite strati- FEET graphic section of the coral-bearing Permian strata in White Pine County, Nevada. ELY LS. 572 W. H. EASTON Permian strata in the area rest with ap- ridge north and south of Moorman Ranch parent concordance upon the Ely limestone in the Illipah quadrangle. It is probable of Early Pennsylvanian age. The Ely lime- that this un-named unit is 2000 feet thick, stone consists of about 1500 feet of massive although the upper part is inadequately to platy, grey limestone. Detailed informa- known. Knight (1956) has published on the tion on the stratigraphy and paleontology fusulinids in the succession. Corals occur in of the Ely limestone will appear in a future some of the limestone beds. number of this journal in an article by Overlying the foregoing sequence at some Bernard O. Lane. places is a massive, white limestone about The basal unit of Permian rocks mapped 200 feet thick. It is referred to in text-figure by us is the Rib Hill formation. Its lower 1 as the "Kaibab" limestone because of its limit is determined by the presence of a position in section. It occurs between strata thin, chert pebble conglomerate. The suc- of Leonard age and strata containing the ceeding limestones account for as much as Phosphoria fauna. Corals are not known 300 feet of section at some localities, but from so-called Kaibab limestone. more generally only the uppermost bed of coralline limestone about 30 feet thick is FAUNAL ANALYSIS present. This massive unit locally is almost The most unusual feature of the Permian a biostrome of colonial corals. It comprises coral fauna from the Basin and Range zone 1 of the coral succession. The remain- Province is the abundance of compound der, and principal part, of the Rib Hill corals belonging to groups with a tendency formation consists of pink to yellow sand- for the development of some sort of axial stone in the eastern facies but becomes in- structure. In Lithostrotionella and Lons- creasingly calcareous and evenly buff in daleia the axial structure may be conspicu- color westward. The arenaceous portion of ous, whereas it is reduced in Diphyphyllum the Rib Hill formation is about 1000 feet and is absent in Thysanophyllum. Lithostro- thick. tionella is noteworthy because this genus is The Arcturus formation overlies the Rib widespread in Meramec strata (Middle Hill formation conformably and comprises Mississippian) from the Appalachian to the about 2000 feet of strata. In its eastern Cordilleran ranges. On the other hand, facies near the type section (as on the west Lithostrotionella has been reported from grade leading up to Murry Summit) the Pennsylvanian and Permian strata of sev- Arcturus formation consists of numerous eral countries, including Canada (Smith, beds of pink to yellow sandstone inter- 1935). Merriam (1942) was the first to re- calated with grey limestone in crudely port Lithostrotionella from Permian strata cyclical alternations. The western facies, in the United States (Leonard of Oregon). however, is even less cyclical in appearance A second notable feature is the localized and the sandstones are more uniformly abundance of very large specimens of buff and are very calcareous. Toward the Caninia. Caninia is common in Late Paleo- western margin of the mapped areas the zoic strata in many regions of the world, in- Rib Hill and Arcturus formations become cluding North America, but never before difficult to differentiate. The base of the (to the writer's knowledge) did species at- Arcturus formation, however, is a wide- tain the breadth of the species described spread, massive succession of limestones hereafter. which contain biostromes of corals referred A third, but negative, phenomenon is the to herein as zone 2.