Lexicon of New For mal Geologic Names 

of the United States 1976-1980 

By GWENDOLYN W. LUTTRELL, MARILYN L. HUBERT, 

and VIRGINIA M. JUSSEN 

U.S. GEOLOGICAL SURVEY BULLETIN 1564 

A compilation of the new geologic names intmduced into 

the litrrature from 1976 to 1980 in the United States, 

Puerto Rico, Panama Canal Zone, and American 

Samoa 

UNITED STATES GOVERNMENT PRINTING OFFICE 1986 
DEPARTMENT OF THE INTERIOR 

DONALD PAUL HODEL, Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Library of Congress Cataloging-in-Publication Data 

Luttrell, Gwendolyn Lewise Werth, 1927-

Lexicon of new formal geologic names of the United States, 1976-1980. 

(U.S. Geological Survey bulletin ; 1564) 

"A compilation of the new geologic names introduced into the literature from 1976-1980 in 

the United States, Puerto Rico, Panama Canal Zone, and American Samoa." 

Supt. of Docs. no.: I. 19.3:1564 

1. Geology, Stratigraphic-Nomenclature-United States. I. Hubert, Marilyn L. II. Jussen, 

Virginia M. III. Title. IV. Series. 

QE75.B9 no. 1564 1986 557.3 s 85--600349 

[QE645] [551. 7'00973] 

For sale by the Distribution Branch, U.S. Geological Survey, 

604 South Pickett Street, Alexandria, VA 22304 
CONTENTS 

Page 

Introduction . . . . . . • . . . . . . • . . . . . . • . . . . . . . . . . . • . . . . • . . . • . • . 1 

Selection of names for the lexicon . . . . . . . • . . . . . . . . . . . . . . . • . • . . 1 

Explanation of format . . • . . . . . . . . . . . . . • . . • . . . . . • . . . . . . . • . . . 2 

Lexicon................................................ 3 

TABLE 

Major geochronologic and chronostratigraphic 

units in use by the U.S. Geological Survey 

Page 

with age estimates of boundaries .....••.......•...•.•......• IV 

m 
IV LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Major geochronologic and chronostratigraphic units in use by the U.S. Geological Survey 

with age estimates of boundaries 

Subdivisions in use by the U.S. Geological Survey {map symbols) Age estimates of 

boundaries in 

Eon or Eonothem Era or Erathem Period or System Epoch or Series million years 1

• 5 

Quaternary Holocene 0.010 - (Q) Pleistocene 

Neogene 2 (1.7-2.2) Pliocene Cenozoic Subperiod or 5 (4.9-5.3) 

Subsystem IN) Miocene (C.) Tert1ary 24 (23-26) 

(T) Paleogene Ol1gocene 38 (34-38) 

Subperood or Eocene 

Subsystem (Pt) 55 (54-56)- Paleocene 63 (63-66) 

Cretaceous Lale Upper r- 96 (95-97)-

(K) Early Lower 

138 (135-141) 

Mesozoic Jurassic Late Upper 

Moddle Moddle (Mz) (J) Early lower 205 (200-215) 

Troassic Late Upper 

Moddle Moddle (li) Early Lower 

240 - Perm1an late Upper 

PhaneroZOIC (P) Early lower 

290 (290-305) 

Pennsylvan1an Lale Upper Carboniferous Moddle Moddle 

Periods or (IP) Early lower -330 - Systems M1ssiss1pp1an Late Upper 

(C) (M) Early lower 

360 (360-365)-

Paleozo1c Devon1an late Upper 

Moddle Moddle (Pz) (D) Early lower 410 (405-415)-

Siluroan Lale Upper 

(S) Moddle Moddle 

Early Lower 

435 (435-440)-

Ordavocian Late Upper 

(0) Moddle Moddle 

Early Lower 500 (495-510)-

Cambroan Late Upper 

Moddle Moddle (£) Early Lower -570 2 

Late ProteroZOIC 3 - IZ) 900 Proterozoic Middle Proterozooc 3 - (!?) (Y) 1600 - Early Proterozoic 3 

(X) 2500 - late Archean 3 

(W) 3000 Archean Middle Archean° - (A) (V) 3400 Early Archean 3 - (U) 

f----.--...___-------~'-~----.......__~---- ~ ---~C-.......__..--.....---------- -....--- ~---... (3800?)___...-- -._/ -..._--._ /""'- ----- ~ 

pre-Archean 4 

(pA) 4550 

1 Ranges reflect uncertainties of isotopic and biostratigraphie age assignments. Age of boundaries not closely bracketed by existing data shown by .... Decay constants and isotopic ratios employed are cited in Steiger and Jager (1977). 

2 Rocks older than 570 Ma also called Precambrian (pC), a time term without specific rank. 

3 Geoehronometrie units. 

4 Informal time term without specific rank. 

5 Age estimates for the Phanerozoic are by G. A. Izett, M.A. Lanphere, M. E. MacLachlan, c. W. Naeser, J.D. Obradovich, Z. E. 

Peterman, M. Rubin, T. W. Stern, and R. E. Zartman at the request of the Geologie Names Committee. Age estimates for the Precambrian are by International Union of Geological Sciences Working Group on the Precambrian for the United States and Mexico, 

J. E. Harrison, Chairman. The chart is intended for use by members of the U.S. Geological Survey and does not constitute a formal proposal for a geologic time seale. Estimates of ages of boundaries were made after reviewing published time scales and other data. 

Future modification of this chart will undoubtedly be required. The general references apply where references are not given for specific boundaries. 

Geologic Names Committee, 1983 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES V 

GENERAL REFERENCES 

American Association of Petroleum Geologists, 1978, Studies in Geology 6, 

388 p. 

Berggren, W. A., 1972, Lethaia, v. 5, no. 2, p. 195-215. 

Evernden, J. F., Savage, D. E., Curtis, G. H., and James, G. T., 1964, 

American Journal of Science, v. 262, p. 145-198. 

Geological Society of London, 1964, Quarterly Journal, v. 120S, 458 p. 

Lambert, R. S., 1971, Geological Society of London, Special Publications 3, 

Part 1, p. 9-31. 

Steiger, R. H., and Jager, E., 1977, Earth and Planetary Science Letters, 

v. 36, p. 359-362. 

Holocene-Pleistocene boundary 

Hopkins, D. M., 1975, Geology, v. 3, p. 10. 

Pleistocene-Pliocene boundary 

Haq, B. U., Berggren, W. A., and Van Couvering, J. A., 1977, Nature, v. 269, 

p. 483-488. 

Selli, R., Accorsi, C. A., Bandini, M. M., Bertolani, M. D., Bigazzi, G., 

Bonadonna, F. P., Borsetti, A. M., Cati, F., Colalongo, M. L., D'onofrio, 

S., Landini, W., Menesini, E., Mezzetti, R., Pasini, G., Savelli, C., and 

Tampieri, R., 1977, Giornale di Geologica Bologna, ser. 2, v. 42, no. 1, 

book n, p. 181-204. 

Pliocene-Miocene boundary 

Cita, M. B., 1975, Micropaleontology, Special Publication 1, p. 1-30. 

McDougall, I., and Page, R. W., 1975, Micropaleontology Special Publication 1, p. 75-84. 

Tongiorgi, E., and Tongiorgi, M., 1964, Nature, v. 201, p. 365-367. 

Van Couvering, J. A., 1972, in Bishop, W. W., and Miller, J. A., eds., 

Calibration of hominid evolution, Scottish Academic Press and 

University of Toronto Press, p. 247-271. 

Miocene-oligocene boundary 

Van Couvering, J. A., 1978, Geology, v. 6, p. 169. 

Van Couvering, J. A., and Berggren, W. A., 1977, in Kauffman, E. G., and 

Hazel, J. E., eds., Concepts and methods of biostratigraphy, 

Stroudsburg, Pa.; Dowden, Hutchinson, & Ross New York ; exclusive 

distributor: Halstead Press, c. 1977. 

Oligocene-Eocene boundary 

Hardenbol, J., and Berggren, W. A., 1978, American Association of 

Petroleum Geologists Studies in Geology 6, p. 213-234. 

Odin, G. S., Curry, D., and Hunziker, J. C., 1978, Journal of the Geological 

Society of London, v. 135, p. 481-497. 

Eocene-Paleocene boundary 

Berggren, W. A., McKenna, M. C., Hardenbol, J., and Obradovich, J. D., 

1978, Journal of Geology, v. 86, p. 67-81. 

Fitch, F. J., Hooker, P. J., Miller, J. A., and Brereton, N. R., 1978, Journal 

of the Geological Society of London, v. 135, p. 499-512. 

Odin, G. S., Curry, D., and Hunziker, J. C., 1978, Journal of the Geological 

Society of London, v. 135, p. 481-497. 

Paleocene-Cretaceous boundary 

Lerbekmo, J. F., Evans, M. E., and Baadsgaard, H., 1979, Nature, v. 279, 

p. 26-30. 

Obradovich, J. D., and Cobban, W. A., 1975, Geological Association of 

Canada Special Paper 13, p. 31-54. 
VI LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Late-Early Cretaceous boundary 

Folinsbee, R. E., Baadsgaard, H., and Cumming, G. L., 1963, National 

Research Council Publication 1075, p. 70-82. 

Obradovich, J. D., and Cobban, W. A., 1970, Geological Association of 

Canada Special Paper 13, p. 31-54. 

Cretaceous-Jurassic boundary 

Lanphere, M. A., and Jones, D. L, 1978, American Association of Petroleum 

Geologists Studies in Geology 6, p. 259-268. 

Jurassic-Triassic boundary 

Armstrong, R. L., and Besancon, J., 1970, Eclogae Geologicae Helvetiae, v. 63, no. 1, p. 15-28. 

White, W. H., Erickson, G. P., Northcote, K. E., Dirom, G. E., and Harakal, 

J. E., 1967, Canadian Journal of Earth Sciences, v. 4, p. 677-690. 

Triassic-Permian boundary 

Webb, A. W., and McDougall, I., 1967, Earth and Planetary Science Letters 2, 

p. 483-488. 

Permian-carboniferous boundary 

Fitch, F. J., Miller, J. A., and Williams, S. C., 1970, International Congress on Stratigraphy and Carboniferous Geology, 6th, Sheffield, 1967, 

Compte Rendu, v. 2, p. 771-789. 

C&rboniferous-Devonian boundary 

Fitch, F. J., Miller, J. A., and Williams, S. C., 1970, International Congress on Stratigraphy and Carboniferous Geology, 6th, Sheffield, 1967, 

Compte Rendu, v. 2, p. 771-789. 

McDougall, I., Compston, W., and Bofinger, V. M., 1966, Geological Society 

of America Bulletin, v. 77, p. 1075-1088. 

Talent, J. A., 1975, in Boucot, A. J., Evolution and extinction rate controls, 

Amsterdam, New York: Elsevier Scientific Pub. Co., p. 63. 

Devonian-8ilurian boundary 

Ross, R. J., Jr., Naeser, C. W., Izett, G. A., Whittington, H. B., Hughes, 

C. P., Rickards, R. B., Zalasiewicz, J., Sheldon, P. R., Jenkins, C. J., 

Cocks, L. R. M., Bassett, M. G., Toghill, P., Dean, W. T., and Ingham, 

J. K., 1978, U.S. Geological Survey Open-File Rept. 78-701, p. 363-365. 

Silurian-Qrdovican boundary 

Lanphere, M. A., Churkin, M., Jr., and Eberlein, G. D., 1977, Geological 

Magazine, v. 114, no. 1, p. 15-24. 

Ross, R. J., Jr., Naeser, C. W., Izett, G. A., Whittington, H. B., Hughes, 

C. P., Rickards, R. B., Zalasiewicz, J., Sheldon, P. R., Jenkins, C. J., 

Cocks, L. R. M., Bassett, M. G., Toghill, P., Dean, W. T., and Ingham, 

J. K., 1978, U.S. Geological Survey Open-File Rept. 78-701, p. 363-365. 

Precambrian subdivisions 

Harrison, J. E., 1980, Geological Society of America Bulletin, v. 91, no. 6, 

p. 377-380. 

Harrison, J. E., and Peterman, Z. E., 1982, American Association of 

Petroleum Geologists Bulletin, v. 66, no. 6, p. 801-802. 

Proterozoic subdivisions 

James, H. L., 1972, American Association of Petroleum Geologists Bulletin, v. 56, p. 1128-1133. 

Proterozoic-Archean boundary 

James, H. L, 1978, Precambrian Research, v. 7, no. 3, p. 193-204. 

Archean 

Goldich, S. S., and Wooden, J. L., 1978, in Smith, I. E. M., and Williams, 

J. G., eds., Proceedings of the 1978 Archean Geochemistry Conference, 

p. 285-318. 
LEXICON OF NEW FORMAL GEOLOGIC NAMES 

OF THE UNITED STATES 

1976-1980 

By Gwendolyn W. Luttrell, Marilyn L. Hubert, 

and Virginia M. ,Jussen 

INTRODUCTION 

This lexicon contains brief descriptions of new formal stratigraphic 

units in the United States, Puerto Rico, Panama Canal Zone, and American 

Samoa introduced into the literature in the years 1976 through 1980. This 

volume is the latest in a series of lexicons published by the U.S. Geological 

Survey as a means of keeping the geologic profession informed of the status 

of geologic names in the United States. 

The following publications list the geologic names introduced in the 

United States before 1976: 

Wilmarth, M. G., 1938, Lexicon of geologic names of the 

United States: U.S. Geological Survey Bulletin 896, two 

volumes. 

Wilson, Druid, Sando, W. J., and Kopf, R. w., 1957, Geologic 

names of North America introduced in 1936-1955: U.S. 

Geological Survey Bulletin 1056-A, 405 p. 

Keroher, G. C., and others, 1966, Lexicon of geologic names of 

the United States for 1936-1960: U.S. Geological Survey 

Bulletin 1200, three volumes. 

Keroher, G. c., 1970, Lexicon of geologic names of the United 

States for 1961-1967: u.s. Geological _survey Bulletin 

1350, 848 p. 

Luttrell, G. w., Hubert, M. L., Wright, W. B., Jussen, V. M., 

and Swanson, R. W ., 1981, Lexicon of geologic names of 

the United States for 1968-1975: U.S. Geological Survey 

Bulletin 1520, 342 p. 

Swanson, R. W ., Hubert, M. L., Luttrell, G. W ., and Jussen, V. 

M., 1981, Geologic Names of the United States through 

1975: U.S. Geological Survey Bulletin 1535, 643 p. 

SELECTION OF NAMES FOR THE LEXICON 

The North American Commission on Stratigraphic Nomenclature, 

recognizing the desirability of uniform usage in stratigraphic classification 

and terminology throughout the continent of North America, formulates a code of recommended procedures for classifying and naming stratigraphic 

units. The 1970 Code of Stratigraphic Nomenclature, which was in effect in 

the years 1976 to 1980, states that proper establishment of a formal geologic name requires publication, in a recognized scientific medium, of a definition 

that includes a statement of intention to designate a formal unit, selection 

of a name, definition of the unit in the type area with specific location of 

the type section, statement or distinguishing characteristics, definition of 

boundaries and contact relationships, description of dimensions and shape, 

statement of geologic age, and correlation. We have attempted to include in 

this lexicon only names that meet these criteria. However, some names that 

1 
2 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

have become established in the literature through use, although not formally 

proposed, are included because they seem to have been intended as formal 

names. Names proposed in abstracts, theses, and geologic guidebooks that are not part of a regularly issued and widely distributerl formal series or names used only in figures, tables, and map explanations are not included. 

The descriptions contain data presented in the naming papers only. Subsequent revisions or age changes are not noted. 

EXPLANATION OF FORMAT 

The format of this lexicon presents in a telegraphic style all information necessary for proper establishment of a formal stratigraphic unit. Each name has been described by following an outline format with 10 numbered 

categories. A key to the format and an explanation of abbreviations and 

conventions used in the text follow. 

Name (not numbered).-The name of a stratigraphic unit consists of a geographic name and a rank or descriptive term. Alternate or additional rank or 

descriptive terms are separated from the first by a "/." Boldface type 

indicates U.S. Geological Survey usage. 

1. Age.-Designated by era, period, or epoch terms. Stage terms are in 

parentheses. Where only dates are given in a reference, we have substituted 

the corresponding era or period term. Equivalent ages supplied by us are in 

brackets []. 

2. Geographic extent.-The State or country in which the unit was first 

described, followed, in parentheses, by the geographic area of the State in 

which the type locality occurs. Then follow the other States in which the 

unit is described. The geographic areas were established by constructing a 

rectangle framed by the maximum and minimum latitudes and longitudes of 

a State and by dividing length and height by 3 to give 9 equal areas: NW, 

NC, NE, EC, C, we, SW, SC, and SE. Not all these areas are present in some irregularly shaped States. 

3. Reference.-The first published article that contains a formal proposal or good description of the new name. 

4. Lithology.--A brief description of principal rock types found in the unit. 

5. Col<r.-The principal colors of the unit. 

6. Thickness.--In meters at the type section. A range is given if stated. 

7. Distinctive features, texture, structure, environment of deposition. 

8. Subdivisions.-Both formally named and informal subdivisions, from older 

to younger. 

9. Adjoining 1Blits.--Including type of contact, if known, from older to 

younger; correlations. 

10. Type section, locality <r area, and derivation of name. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

LEXICON 

Aggie Brown Member (Oahe Formation) 

1. Pleistocene (Wisconsinan) and Holocene 

2. North Dakota (C) 

3. Clayton, Lee, Moran, S. R., and Bickley, W. B., Jr., 1976, 

Stratigraphy, origin, and climatic implications of late 

Quaternary upland silt in North Dakota: North Dakota Geol. 

Survey Misc. Ser., no. 54, p. 3-5 

4. Silt, clay, and sand 

5. Light-brown, dark-gray 

6. 0.35 m, range 0.1-0.5 m 7. Charcoal and red baked zones caused by forest fires 

9. Overlies Mallard Island Member; underlies Pick City Member 

10. Type section: Riverdale Section, bluffs of Lake Sakakawea, 

center sec. 22, T. 147 N., R. 84 W., 4 km N of Riverdale, 

McLean County, N. Oak. Named for Aggie Brown Coulee, which 

flows into Lake Sakakawea. 

Alburnett Formation 

1. Pleistocene (pre-Illinoian) 

2. Iowa (EC) 

3. Hallberg, G. R., 1980, Pleistocene stratigraphy in eastcentral Iowa: Iowa Geol. Survey Tech. Inf. Ser., no. 10, 

p. 70-93 

4. Till, fluvial sediments, paleosols 

5. Yellowish-brown to dark-gray 

6. 10 m, range <1-76 m 

7. Loam-textured till high in expandable clays, kaolinite, and 

illite 

8. Several till units separated by silt, sand, and gravel, 

organic material and paleosols 

9. Unconformably overlies Paleozoic bedrock; unconformably 

underlies Wolf Creek Formation 

10. Type section: Little Paha core section, in roadcut through 

center of small paha, near town of Alburnett, 

NW1/4NW1/4SW1/4SW1/4 sec. 17, T. 85 N., R. 7 W., Linn 

County, Iowa. 

A-L Peak 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Rhyolite 

Oligocene 

New Mexico (WC) 

Deal, E. G., and Rhodes, R. C., 1976, Volcano-tectonic 

structures in the San Mateo Mountains, Socorro County, New 

Mexico: New Mexico Geol. Soc. Spec. Pub. 5, p. 54 

Rhyolite ash-flow tuff 

Gray to purple 

700 m, range 50-700 m 

Welded; foliated; erupted from Mount Withington cauldron 

Unconformably overlies Hells Mesa Rhyolite or Vicks Peak 

Rhyolite; underlies Potato Canyon Rhyolite 

Type locality: NE flank of A-L Peak, N San Mateo Mountains, 

sees. 33-35, T. 4 S., R. 6 W., Socorro County, N.Mex. 

Anapra Sandstone 

1. Early Cretaceous 

2. New Mexico (SC), Texas, Mexico 

3. Strain, W. S., 1976, New formation names in the Cretaceous 

3 
4 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

at Cerro de Cristo Rey, Dofta Ana County, New Mexico, Appendix 2 in Lovejoy, E. M. P., Geology of Cerro de Cristo Rey 

uplift:-Chihuahua and New Mexico: New Mexico Bur. Mines and 

Mineral Resources Mem. 31, p. 81-82 

Quartz sandstone with siliceous shale beds 

Orange, brown 

53 m 

Thin-bedded to massive, forms high ridges 

Conformably overlies Mesilla Valley Shale; conformably 

underlies Del Rio Clay 

Type section: On E side of road to Cerro de Cristo Rey and 

E of abandoned site of Bowen; SW1/4SE1/4SW1/4 sec. 9, 

T. 29 S., R. 4 E., Smeltertown quadrangle, Dofta Ana County, 

N. Mex. Named for town of Anapra. 

Antelope Mountain Quartzite 

1. Ordovician(?) 

2. California (NW) 

3. Hotz, P. E., 1977, Geology of the Yreka quadrangle, Siskiyou 

County, California: U.S. Geol. Survey Bull. 1436, p. 17-19 

4. Quartz arenite with chert beds 

5. Greenish-gray, gray, brown, tan 

6. Range 1,500-1,700 m 

1. Well-bedded, medium- to coarse-grained 

9. Overlies Duzel Phyllite; contacts modified by faulting; 

underlies Cretaceous and Tertiary rocks 

10. Type locality: Main ridge of Antelope Mountain, sees. 26 

and 35, T. 44 N., R. 7 W., and sees. 2, 3, and 10, T. 43 N., 

R. 7 W., Siskiyou County, Calif. 

Appleton 

1. 

2. 

3. 

4. 

6. 

7. 

8. 

9. 

10. 

Ridge Formation 

Early Devonian 

Maine (SC) 

Bickel, C. E., 1976, Stratigraphy of the Belfast quadrangle, 

Maine: Geol. Soc. America Mem. 148, p. 108-110 

Lower andalusite zone: staurolite schist; garnet zone: phyllite with minor garnet; Muzzy Ridge Member: cummingtonite-garnet schist 

1,200 m Bedded, sheared 

Muzzy Ridge Member 

Conformably overlies Bucksport Formation; in fault contact 

with Jam Brook Formation to SW and Penobscot Formation to NE 

along St. George fault. Unit was formerly informal Appleton 

formation of Cheney (1967) 

Type area: Appleton Ridge, Knox and Waldo Counties, Maine. 

Arco Bills Formation 

1. Late Mississippian (Chesterian) 

2. Idaho (SC) 

3. Skipp, Betty, and others, 1979, Upper Paleozoic carbonate 

bank in east-central Idaho--Snaky Canyon, Bluebird Mountain, 

and Arco Hills Formations, and their paleotectonic significance: U.S. Geol. Survey Bull. 1486, p. 11-18 

4. Interbedded limestone, mudstone, shale, siltstone, and minor 

sandstone 

5. Medium-gray, olive-gray, yellowish-brown, grayish-red 

6. 75.7 m, range 52-93 m 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

1. Thin-bedded, slope-forming, fossiliferous 

9. Gradationally overlies Surrett Canyon Formation; gradationally or unconformably underlies Bluebird Mountain Formation 

10. Type section: Exposures in Arco Hills, 1 km E of town of 

Arco, N1/2NE1/4 sec. 31, T. 4 N., R. 27 E., Butte County, 

Idaho. 

Argusville Formation 

1. Pleistocene (Wisconsinan) 

2. North Dakota (EC) 

3. Arndt, B. M., 1977, Stratigraphy of offshore sediment, Lake 

Agassiz--North Dakota: North Dakota Geol. Survey Rept. 

Inv. 60, p. 11 

4. Clay 

5. Gray 

6. 5.5 m 

1. Lacustrine, unbedded, with marbled appearance; contains 

balls of silt and pebble-loam 

9. Overlies pebble-loam; conformably underlies Brenna Formation 

or unconformably underlies Sherack Formation; grades laterally into Huot Formation 

10. Type section: Boring 2, North Dakota State Highway Dept. 

Aroostook 

1 • 

2. 

3. 

4. 

5. 

6. 

1. 

9. 

10. 

Structure I-29-89, Rose Coulee Bridge, SW1/4SW1/4SW1/4 

sec. 26, T. 139 N., R. 49 W., Cass County, N. Dak. Named 

for village of Argusville. 

River Formation 

Late Ordovician and (or) Early Silurian (Ashgillian and 

early Llandoverian) 

Maine (NE) 

Roy, D. C., and Mencher, Ely, 1976, Ordovician and Silurian 

stratigraphy of northeastern Aroostook County, Maine: Geol. 

Soc. America Mem. 148, p. 31, 48 

Calcareous slate interlayered with graywacke and siltstone 

Gray to green-gray 

600 m 

Thin-bedded 

Overlies Madawaska Lake Formation; conformably underlies 

Frenchville Formation 

Type area: 4.0 km stretch of Aroostook River beginning 

8.7 km downstream from Maine Route 11 crossing in Ashland, 

Aroostook County, Maine. 

Asotin Member (Saddle Mountains Basalt) 

1.' Miocene, middle 

2. Washington (SE), Idaho 

3. Swanson, D. A., and others, 1979, Revisions in stratigraphic 

nomenclature of the Columbia River Basalt Group: u.s. Geol. 

Survey Bull. 1457-G, p. G43-G44 

4. Olivine- and plagioclase-phyric basalt 

6. 42 m 

1. Single thick hackly jointed flow, peperitic at top, cliffforming 

9. Unconformably overlies Wilbur Creek Member; conformably 

underlies Weissenfels Ridge Member; locally has invasive 

sill-like relation to enclosing sedimentary rocks 

10. Type locality: Roadcuts along Cloverland Grade, NE1/4SE1/4 

5 
6 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

sec. 26 and NW1/4 and SW1/4 of SW1/4 sec. 25, T. 10 N., 

R. 45 E., 5 km WSW of Asotin, Asotin County, Wash. 

Aurora Till Member (Wolf Creek Formation) 

1. Pleistocene (pre-Illinoian) 

2. Iowa (NE) 

3. Hallberg, G. R., 1980, Pleistocene stratigraphy in eastcentral Iowa: Iowa Geol. Survey Tech. Inf. Ser., no. 10, 

p. 38-54 

4. Silty till, pebble loam 

5. Yellowish-brown to greenish-gray 

6. Range 6-11 m 

1. Loam-textured 

9. Unconformably overlies Winthrop Till Member or older units; 

underlies and grades into Dysart paleosol; unconformably 

underlies Hickory Hills Till Member 

10. Type locality: Aurora drilling transect, a series of core 

holes o.n divide between Wapsipinicon and Maquoketa Rivers, 

3.2 km SW of town of Aurora, NE1/4 sec. 23, T. 90 N., 

R. 8 W., Buchanan County, Iowa. 

Baada Point Member (Makah Formation) 

1. Eocene, late 

2. Washington (NW) 

3. Snavely, P. D., Jr., and others, 1980, Makah Formation--a 

deep-marginal-basin sequence of late Eocene and Oligocene 

age in the northwestern Olympic Peninsula, Washington: U.S. 

Geol. Survey Prof. Paper 1162-B, p. 9-11 

4. Sandstone with siltstone interbeds and calcareous concre- tions 

5. Light-olive-gray, weathers yellow-brown 

6. 120 m 

1. Thick-bedded, amalgamated turbidite beds, ridge-forming 

9. Gradationally overlies and underlies unnamed strata in lower 

part of Makah Formation 

10. Type section: Wave-cut platform and headland exposures at 

Baada Point, SE1/4NW1/4 sec. 12, T. 33 N., R. 15 W., Strait 

of Juan de Fuca, Clallam County, Wash. 

Back Creek Siltstone Member (Brallier Formation) 

1. Late Devonian 

2. Virginia (C), West Virginia 

3. Avary, K. L., and Dennison, J. M., 1980, Back Creek Siltstone Member of Devonian Brallier Formation in Virginia and 

West Virginia: Southeastern Geology, v. 21, no. 2, p. 121-

153 

4. Siltstone interbedded with shale and silty shale 

5. Olive-gray, weathers yellowish brown 

6. 20.8 m, range 20.8-34 m 

1. Thin- to thick-bedded, fractured, turbidite deposits 

9. Base is 15-60 m above base of Brallier Formation 

10. Type section: Roadcuts along farm road on NE side of U.S. 

Route 250, E of valley of Back Creek, NW flank of Lantz 

Mountain, Hightown quadrangle, Highland County, Va. 

Balls Bluff Siltstone (Newark Group) 

1. Late Triassic 

2. Virginia (NE), Maryland 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

3. Lee, K. Y., 1977, Triassic stratigraphy in the northern part 

of the Culpeper basin, Virginia and Maryland: U.S. Geol. 

Survey Bull. 1422-C, p. C5 

4. Calcisiltite with layers of oolitic limestone, dolomite, and 

sandstone 

5. Red 

6. 40 m, range 40-2,190 m 1. Laminated, thick-bedded 

9. Overlies Manassas Sandstone (Newark Group); underlies and 

intertongues with Bull Run Formation (Newark Group) 

10. Type section: Exposures in gully 412 m N. 4° E. from flagpole of Balls Bluff National Cemetery, SE Waterford quadrangle, Loudoun County, Va. 

Barboursville Conglomerate Member (Bull Run Formation) 

1. Late Triassic 

2. Virginia (C) 

3. Lindholm, R. C., 1979, Geologic history and stratigraphy of 

the Triassic-Jurassic Culpeper basin, Virginia: Geol. Soc. 

America Bull. (pts. 1 and 2), v. 90, no. 11, p. 996 (pt. 1, 

summary); p. 1723-1724 (pt. 2, microfiche) 

4. Silicate and arkosic sandstone conglomerate 

5. Grayish-maroon matrix 

6. 150 m 

7. Clasts derived from Catoctin and Fauquier Formations 

10. Type locality: Exposures near original Barbour Estate 

(Barbour Ruins), S of Barboursville, Culpeper basin, Orange 

County, Va. 

Barn Hills Member (Ely Springs Dolomite) 

1. Late Ordovician 

2. Utah (WC), Nevada 

3. Budge, D. R., and Sheehan, P.M., 1980, The Upper Ordovician 

through Middle Silurian of the eastern Great Basin--Pt. 1, 

Introduction--historical perspective and stratigraphic synthesis; Pt. 2, Lithologic descriptions: Milwaukee Public 

Mus. Contr. Biology and Geology, no. 28, p. 13-15 (pt. 1); no. 29, p . 22 ( pt . 2) 

4. Dolomite 

5. Brownish-gray, gray 

6. 48 m 

1. Microcrystalline to finely crystalline, thin- to thickbedded, laminated 

9. Overlies Ibex Member; underlies Lost Canyon Member 

10. Type section: Exposures 3.2 km NNW of Ibex Well bench mark 

4779, SE1/4NW1/4 sec. 26, T. 21 S., R. 14 W., Barn Hills, 

Confusion Range, Millard County, Utah. 

Basin Gulch Quartzite Member (Phi Kappa Formation) 

1. Early Ordovician 

2. Idaho (SC) 

3. Dover, J. H., Berry, W. B. N., and Ross, R. J., Jr., 1980, 

Ordovician and Silurian Phi Kappa and Trail Creek Formations, Pioneer Mountains, central Idaho--stratigraphic and 

structural revisions, and new data on graptolite faunas: 

U.S. Geol. Survey Prof. Paper 1090, p. 10-11 

4. Quartzite 

5. Gray 

7 
8 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

<60 m 

Fine-grained, locally pebbly, containing well-sorted and 

well-rounded grains 

Overlies younger rocks in thrust contact; as basal member, 

gradationally underlies black, graptolitic argillite of main 

body of Phi Kappa Formation 

Type locality: Exposures NW of junction of Basin Gulch and 

Trail Creek, near E edge of Rock Roll Canyon quadrangle, 

Blaine County, Idaho. Named for Basin Gulch, northern Pio- neer Mountains. 

Bass River Formation 

1. Late Cretaceous 

2. New Jersey (SE) 

3. Petters, S. W., 1976, Upper Cretaceous subsurface stratigraphy of Atlantic Coastal Plain of New Jersey: Am. Assoc. 

Petroleum Geologists Bull., v. 60, no. 1, p. 93-96 

4. Clayey silt with shell fragments, occasionally cemented into 

massive limestone 

5. Olive-gray to olive-black 

6. 62 m, range 62-126 m 

7. Subsurface; represents marine transgression 

9. Unconformably overlies Potomac Group; underlies Raritan and 

Magothy Formations undivided 

10. Type section: Transcontinental Gas Pipe Line Corporation TC 

16 well, depth-interval 442-504 m, Cutts Brothers Farm, Bass 

River Township, Burlington County, N.J. 

Bear canyon Member (Oquirrh Formation) 

1. Middle Pennsylvanian (Atokan and Desmoinesian) 

2. Utah (NC) 

3. Baker, A. A., 1976, Geologic map of the west half of the 

Strawberry Valley quadrangle, Utah: U.S. Geol. Survey Misc. 

Inv. Ser. Map I-931, p. 2 

4. Limy to quartzitic sandstone interbedded with limestone and 

chert 

5. 

6. 

7. 

9. 

10. 

Bear Den 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

Gray-to-tan, reddish-brown, black 

2,550 m, range 1,200-2,550 m Fossiliferous (fusulinids) 

Overlies Bridal Veil Limestone Member; underlies Shingle 

Mill Limestone Member 

Type locality: Exposed on crest of ridge N of Bear Canyon 

that is continuation of Wallsburg Ridge extending W from 

SE1/4 sec. 16, T. 5 s., R. 4 E., Wasatch County, Utah. 

Member (Golden Valley Formation) 

Paleocene 

North Dakota (WC) 

Hickey, L. J., 1977, Stratigraphy and paleobotany of the 

Golden Valley Formation (early Tertiary) of western North 

Dakota: Geol. Soc. America Mem. 150, p. 17-28 

Kaolinitic claystone, mudstone, sandstone 

White, gray, orange 

10.4 m, range 6-20 m Fossiliferous, channel-facies deposits; forms barren, steep 

slopes 

Informal Alamo Bluff lignite-Taylor bed 

Conformably overlies Fort Union Formation; conformably 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

underlies Camels Butte Member (Golden Valley Formation) 

10. Type section: Section 14122, S of Blue Buttes, on tributary 

of Bear Den Creek, 12 km NW of Mandaree, NE1/4NE1/4 sec. 5, 

T. 150 N., R. 94 W., McKenzie County, N. Oak. 

Beartrap Canyon Formation 

1. Oligocene 

2. New Mexico (WC) 

3. Deal, E. G., and Rhodes, R. C., 1976, Volcano-tectonic 

structures in the San Mateo Mountains, Socorro County, New 

Mexico: New Mexico Geol. Soc. Spec. Pub. 5, p. 55-56 

4. Rhyolite flows and domes, tuff, mudflow breccia, clastic 

sedimentary rocks 

6. 250 m 

1. Erupted from Mount Withington cauldron 

9. Unconformably overlies Potato Canyon Rhyolite; youngest rock 

of Mount Withington cauldron flows 

10. Type locality: Beartrap Canyon, N San Mateo Mountains, 

sees. 7 and 18, T. 6 S., R. 7 W., Socorro County, N.Mex. 

Bear Valley Formation 

1. Miocene, early and middle 

2. California (C) 

3. Axelrod, D. I., 1980, Contributions to the Neogene paleobotany of central California: California Univ. Pubs. Geol. 

Sci., v. 121 ,. p. 19-20 

4. Alternating lenses of volcanic conglomerate, sandstone, and 

andesite tuff 

6. 240 m 

1. Poorly lithified 

9. Overlies Valley Springs Formation or interfingers with 

Underwood Mudflow Breccia; underlies Relief Peak Formation 

10. Type locality: Exposures along Lake Valley Road which 

departs from highway to Mount Reba Ski Bowl at Poison 

Canyon, Alpine County, Calif. Named for outcrops on NE wall 

of Bear Valley. 

Beaucoup Fonaation 

1. Late Devonian 

2. Alaska (NC) 

3. Dutro, J. T., Jr., and others, 1979, Beaucoup Formation, a 

new Upper Devonian stratigraphic unit in the central Brooks 

Range, northern Alaska: U.S. Geol. Survey Bull. 1482-A, 

p. A62-A69 

4. Assorted clastic and carbonate rocks including reefs and 

reefoid layers 

5. Black, brown, yellowish-brown 

6. 150 m, range 150-545 m 

1. Thin- to medium-bedded, fine- to very fine grained, fossiliferous 

9. Unconformably overlies Skajit Limestone; conformably underlies Hunt Fork Shale 

10. Type section: Section on NE side of Beaucoup Creek, 

sees. 19 and 20, T. 14 s., R. 20 E., Philip Smith Mountains 

A-1 quadrangle, central Brooks Range, Alaska. 

Beaver Brook Member (Nashoba Formation) 

1. pre-Silurian 

9 
10 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Massachusetts (C) 

Bell, K. G., and Alvord, D. c., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 184-185, 208, app. 1 (in pocket) 

Sillimanitic biotite gneiss, amphibolite, schist, calcsilicate rocks 

Medium-gray 

1,580 m 

Medium-grained, stratified, relict sedimentary structures 

Overlies Long Pond Gneiss Member (Nashoba Formation); underlies Tadmuck Brook Schist 

Type locality: Area bounded on NE by Mill Road and on SE by 

Foster Street in town of Littleton, on SW by Old TurnpikeLittleton County Road in towns of Boxborough and Harvard, 

and on NW by SE foot of Oak Hill in towns of Harvard and 

Littleton; Ayer, Hudson, and Westford quadrangles, Middlesex 

County, Mass. Derivation of name not stated. 

Beaver Run Member (Ontelaunee Formation) 

1. Early Ordovician 

2. New Jersey (NC) 

3. Markewicz, F. J., and Dalton, Richard, 1977, Stratigraphy 

and applied geology of the lower Paleozoic carbonates in 

northwestern New Jersey--Field Conference of Pennsylvania 

Geologists, 42d, Stroudsburg, 1977, Guidebook: [Harrisburg, 

Pennsylvania Geol. Survey] p. 22 

4. Dolomite with chert beds 

5. Black 

6. Range 45-61 m 

7. Sparkly, emits fetid odor when struck, massive; fossiliferous 

9. Overlies Lafayette Member (Epler Formation); underlies 

Harmonyvale Member (Ontelaunee Formation) 

10. Type section: Not stated, although unit is included in 

measured sections. Probably named for Beaver Run, a tributary of Wallkill River, or for village of Beaver Run, both W 

of Hamburg, Sussex County, N.J. 

Belgrade Formation 

1. Miocene, early 

2. North Carolina (EC) 

3. Ward, L. W., Lawrence, D. R., and Blackwelder, B. W., 1978, 

Stratigraphic revision of the middle Eocene, Oligocene, and 

lower Miocene--Atlantic Coastal Plain of North Carolina: 

U.S. Geol. Survey Bull. 1457-F, p. F13-F16 

4. Oyster-shell beds and phosphatic, calcareous, clayey, shelly 

quartz sands 

5. Tan to orange, gray to brown 

6. 3 m, range 3-31 m 7. Unconsolidated. Members represent penecontemporaneous nearshore and offshore facies 

8. Pollocksville and Haywood Landing Members 

9. Unconformably overlies River Bend Formation; unconformably 

underlies Duplin Formation 

10. Type locality: Martin Marietta Co. Belgrade quarry, just E 

of intersection of County Route 1434 and U.S. Highway 17, 

Belgrade, Onslow County, N.C. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Belleville Tuff 

1. Oligocene, late 

2. Nevada (WC) 

3. Speed, R. C., and Cogbill, A. H., 1979, Cenozoic volcanism 

of the Candelaria region, Nevada: Geol. Soc. America Bull., 

Part II, v. 90, no. 2, p. 456-493 

4. Pumiceous ash-flow tuff 

6. 80 m 7. Two cooling units each with less compacted basal zone, 

intermediate vitrophyre, and thick compacted upper zone 

10. Type locality: East flank of hills 2.3 km s. 20° E. of 

Belleville site, Candelaria Hills, Mineral County, Nev. 

Bellows Bill Member (Nashoba Formation) 

1. pre-Silurian 

2. Massachusetts {C) 

3. Bell, K. G., and Alvord, D. c., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 186-187, 208, app. 1 (in pocket) 

4. Sillimanitic biotite gneiss with amphibolite 

5. Medium-gray 

6. 1,100 m 

1. Medium-grained, stratified; relict sedimentary structures 

9. Overlies Boxford Member; underlies Billerica Schist Member 

10. Type locality: NW part of town of Concord, BOO m W of junction of Lowell Road and Westford Road on S and W sides of 

Bemis Estate, Maynard quadrangle, Middlesex County, Mass. 

[Probably named for Bellows Hill, a hill N of Concord.] 

Benton Spring Group 

1. Oligocene 

2. Nevada (WC) 

3. Ekren, E. B., and others, 1980, Stratigraphy, preliminary 

petrology, and some structural features of Tertiary volcanic 

rocks in the Gabbs Valley and Gillis Ranges, Mineral County, 

Nevada: U.S. Geol. Survey Bull. 1464, p. 11-29 

4. Rhyodacite, quartz latite, and rhyolite tuffs 

5. Gray 

6. Range 170-900 m 1. Multiple-flow cooling units 

8. Mickey Pass Tuff with its Guild Mine and Weed Heights 

Members, Singatsee Tuff, and Petrified Spring Tuff 

9. Overlies lavas of Giroux Valley; underlies intermediate 

lavas or Blue Sphinx Tuff 

10. Type locality: Benton Spring, T. 9 N., R. 34 E., Gabbs 

Valley Range, Mineral County, Nev. 

Berg Creek For.ation 

1. Early Cretaceous (Hauterivian and Barremian) 

2. Alaska (EC) 

3. MacKevett, E. M., Jr., and others, 1978, Geologic map of the 

McCarthy C-8 quadrangle, Alaska: U.S. Geol. Survey Geol. 

Quad. Map GQ-1418 

4. Bioclastic sandy limestone with conglomerate 

5. Light-gray, brown, greenish-gray, buff 

6. 250 m 7. Massive to medium-bedded, crossbedded, fossiliferous, nearshore marine deposits 

11 
12 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Unconformably overlies Triassic rocks or nonconformably 

overlies Chitina Valley batholith (Late Jurassic); gradationally underlies Kuskulana Pass Formation 

Type section: Exposures extend S from SE1/4SW1/4 sec. 34, 

T. 3 S., R. 9 E., to SE1/4NW1/4 sec. 3, T. 4 S., R. 9 E., 

from W of Berg Creek to 1.8 km S of Kuskulana Pass, McCarthy 

C-8 quadrangle, Wrangell Mountains, Alaska. 

Bernhardt Mountain Member (Peck Lake Formation) 

1. [Middle Proterozoic] 

2. New York (EC) 

3. McLelland, James, and Isachsen, Yngvar, 1980, Structural 

synthesis of the southern and central Adirondacks--a model 

for the Adirondacks as a whole and plate tectonics interpretations: Geol. Soc. America Bull. (pt. 2, microfiche), v. 

91, no. 2, p. 226-227 

4. Quartzofeldspathic gneiss 

7. Megacrystic 

9. Overlies kinzigite of Peck Lake Fprmation; underlies Green 

Lake Formation 

10. Type locality: Bernhardt Mountain, NE corner Caroga Lake 

quadrangle, Fulton County, N.Y. 

Bernice Formation 

1. Late Triassic 

2. Nevada (WC) 

3. Speed, R. C., 1976, Geologic map of the Humboldt lopolith 

and surrounding terrane, Nevada: Geol. Soc. America Map and 

Chart Ser. MC-14, p. 2 · 4. Mudstone with minor wacke, quartz arenite, and limestone 

6. 2,600 m 

9. Overlies Triassic pelite; conformably underlies Hoyt Canyon 

Formation 

10. Type locality: Not stated. Probably named for exposures in 

Bernice Canyon, T. 22 N., R. 37 E., Clan Alpine Mountains, 

Churchill County, Nev. 

Big Canyon Latite (Tintic Mountain Volcanic Group) 

1. Oligocene, middle 

2. Utah (C) 

3. Morris, H. T., and Lovering, T. s., 1979, General geology 

and mines of the East Tintic mining district, Utah and Ju~b 

Counties, Utah: U.S. Geol. Survey Prof. Paper 1024, p. 40-

41 

4. Latite airfall tuff and flow 

5. Tuff: white-stained yellow, brown, and black; flow: 

medium- to dark-gray 

6. Tuff: 38 m; flow: 29 m 

7. Tuff: fine-grained, bedded, moderately to strongly altered; 

flow: compact, finely porphyritic, planar partings 

8. Informal lower tuff member and upper flow member 

9. Unconformably overlies Latite Ridge Latite (Tintic Mountain 

Volcanic Group) or Packard Quartz Latite; unconformably 

underlies Pinyon Queen Latite (Laguna Springs Volcanic 

Group) 

10. Type locality: Latite capping E-trending ridge that marks 

S side of entrance to Big Canyon, NW1/4 sec. 13, T. 10 s., 
Big Creek 

1 0 

2. 

3. 

4. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

R. 2 W., East Tintic Mountains, 16 km SW of East Tintic 

mining district, Juab County, Utah. 

Gneiss 

Early Proterozoic 

Wyoming (SC) 

Divis, A. F., 1976, Geology and geochemistry of Sierra Madre 

Range, Wyoming: Colorado School Mines Quart., v. 71, no. 3, 

p. 14-18 

Hornblende and feldspathic gneiss 

Banded and augen gneiss, foliated to granoblastic; coarse- grained pegmatites 

In gradational contact with Sierra Madre Granite; underlies 

and intergrades with Green Mountain Formation 

Type area: Exposed along banks of Big Creek and margins of 

Big Creek Park, SE Sierra Madre Range, Carbon County, Wyo. 

Big Elk Creek Member (James Run Formation) 

1. Paleozoic, early 

2. Maryland (NE), Delaware 

3. Higgins, M. W., 1977, Six new members of the James Run 

Formation, Cecil County, northeastern Maryland: U.S. Geol. 

Survey Bull. 1435-A, p. A126 

4. Quartz-plagioclase-hornblende amphibolite and felsite 

5. Dark-green, gray 

6. 305 m 1. Interlayered, layers 3-12 em thick, of metavolcanic and 

metasedimentary origin 

9. Gradationally overlies Gilpins Falls Member; probably partly 

equivalent to Happy Valley Branch and Principio Creek 

Members 

10. Type section: Exposures along Big Elk Creek, Cecil County, 

Md. 

Big Horse Limestone Meaber (Orr Formation) 

1. Late Cambrian 

2. Utah (WC) 

3. Hintze, 1. F., and Palmer, A. R., 1976, Upper Cambrian Orr 

Formation--its subdivisions and correlatives in western 

Utah: U.S. Geol. Survey Bull. 1405-G, p. G4-G5, G15-G18 

4. Limestone, calcarenite 

5. Gray 

6. 217.9 m 1. Fossiliferous, cliff-forming 

9. In type section, conformably overlies Weeks Limestone, 

conformably underlies Candland Shale Member (Orr Formation); 

in Wah Wah Mountains, overlies Wah Wah Summit Formation, 

conformably underlies Steamboat Pass Shale Member (Orr 

Formation) 

10. Type section: NE side of Orr Ridge, on NE face of hill 

6593, SE1/4 sec. 28, T. 18 s., R. 13 W., and along ridge 

between Little Horse Canyon and Big Horse Canyon, NE1/4 

sec. 33, T. 18 s., R. 13 W., House Range, Notch Peak quadrangle, Millard County, Utah. 

Big Springs Member (Epler Formation) 

1. Early Ordovician 

2. New Jersey (NC) 

13 
14 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Markewicz, F. J., and Dalton, Richard, 1977, Stratigraphy 

and applied geology of the lower Paleozoic carbonates in 

northwestern New Jersey--Field Conference of Pennsylvania 

Geologists, 42d, Stroudsburg, 1977, Guidebook: Harrisburg, 

Pennsylvania Geol. Survey p. 21 

Dolomite and limestone, with bands of siliceous shale and 

quartzite 

Gray, weathers red to orange or pale blue 

Range 12-46 m 

Fine- to medium-grained, banded 

Overlies Branchville Member; underlies Lafayette Member 

Type section: Not stated, although unit is described in 

measured sections. Probably named for Big Spring, a spring 

on NW side of New Jersey Route 94 about 5 km SW of Hamburg, 

Sussex County, N.J. 

Billerica Schist Member (Nashoba Formation) 

1. pre-Silurian 

2. Massachusetts (C) 

3. Bell, K. G., and Alvord, D. C., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 186-187, 208, app. 1 (in pocket) 

4. Sillimanite-muscovite-biotite schist 

5. Weathers rusty 

6. 270 m 

1. Stratified, relict sedimentary structures 

9. Overlies Bellows Hill Member; underlies Spencer Brook Member 

10. Type locality: SE side of Fox Hill and along Concord River 

from its crossing by U.S. Highway 3 SW to vicinity of Riverside, in town of Billerica, Billerica quadrangle, Middlesex 

County, Mass. 

Black Box Dolomite 

1. Late Permian 

2. Utah (EC) 

3. Welsh, J. E., Stokes, W. L., and Wardlaw, B. R., 1979, 

Regional stratigraphic relationships of the Permian "Kaibab" or Black Box Dolomite of the Emery high, central Utah, in 

Baars, D. L., ed., Permianland: Four Corners Geol. Soc~ 

Field Conf., 9th, 1979, Guidebook, p. 143-149 

4. Dolomite with cherty dolomite 

5. Gray 

6. 26 m, range 26-56 m 

1. Finely crystalline 

9. Unconformably overlies Cedar Mesa Sandstone; unconformably 

underlies Black Dragon Member (Moenkopi Formation). Was 

described as the "Kaibab" Limestone by Gilluly and Reeside 

(1927) at Black Box Canyon 

10. Type section: Exposures 0.8 km S of head of Black Box 

Canyon of San Rafael River, San Rafael Swell, Emery County, 

Utah. 

Black Dyke Formation 

1. Permian 

2. Nevada (WC) 

3. Speed, R. C., 1977, Excelsior Formation, west central 

Nevada--stratigraphic appraisal, new divisions, and paleogeographic interpretations, in Stewart, J. H., and others, 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 15 

eds., Paleozoic paleogeography of the western United States--

Pacific Coast Paleogeography Symposium 1 [Bakersfield, CA, 

1977J: Los Angeles, Soc. Econ. Paleontologists and 

Mineralogists, Pacific Sec., p. 334-335 

4. Mafic volcanic breccia with minor intercalated volcanogenic 

sedimentary rocks, lavas, and intrusive rocks 

1. Allochthonous thrust nappe 

9. Overlies, in thrust-fault contact, Triassic and Jurassic 

sedimentary rocks; unconformably underlies Tertiary 

volcanics intruded by Late.Cretaceous(?) granitic rocks 

10. Type area: Black Dyke Mountain, E Garfield Hills, Mineral 

County, Nev. 

Blackwater Draw Formation 

1. Pleistocene (Illinoian) 

2. Texas (NC), New Mexico 

3. Reeves, c. C., Jr., 1976, Quaternary stratigraphy and geologic history of southern High Plains, Texas and New Mexico, 

in Mahaney, W. C., ed., Quaternary stratigraphy of North 

America: Stroudsburg, Pa., Dowden, Hutchinson and Ross, 

p. 219, 222 

4. Sand, sandy clay loam 

5. Reddish-brown to tan 

6. Range <1-27 m 

1. Eolian origin 

9. Unconformably overlies "caprock" caliche of Ogallala Group 

or basal Illinoian gray sand; unconformably underlies 

Peoria(?) loess or is present at surface 

10. Type section: Outcrop on W side of Blackwater Draw W of New 

Deal, lat 33°46'00" N., long 101°52'30" W., Lubbock County, 

Tex. 

Blooa Member (Snaky Canyon Formation) 

1. Late Mississippian to Late Pennsylvanian (Chesterian to 

Missourian) 

2. Idaho (SE) 

3. Skipp, Betty, and others, 1979, Upper Paleozoic carbonate 

bank in east-central Idaho--Snaky Canyon, Bluebird Mountain, 

and Arco Hills Formations, and their paleotectonic significance: U.S. Geol. Survey Bull. 1486, p. 21-28 

4. Limestone interbedded with sandstone or siltstone; contains 

chert nodules 

5. Medium-gray to medium-dark-gray 

6. 647 m 1. Ledge-forming, very fine to coarse-grained, fossiliferous 

9. Gradationally overlies Bluebird Mountain Formation; gradationally underlies Gallagher Peak Sandstone Member (Snaky 

Canyon Formation) 

10. Type section: Exposures on Gallagher Peak, sees. 29 and 30, 

T. 10 N., R. 31 E., and sec. 21, T. 9 N., R. 32 E., Copper 

Mountain quadrangle, Clark County, Idaho. Named for Bloom 

triangulation station, 2.7 km S of Gallagher Peak. 

Bloomer Bill Formation 

1. Jurassic 

2. California (NW) 

3. Hietanen, Anna, 1977, Paleozoic-Mesozoic boundary in the 

Berry Creek quadrangle, northwestern Sierra Nevada, Califor-
16 

4. 

5. 

6. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

nia: U.S. Geol. Survey Prof. Paper 1027, p. 8-17 

Metavolcanic rocks including metadacite, metasodarhyolite, 

meta-andesite, metabasalt, metatuff, and tuffaceous 

metasedimentary rocks 

Greenish-gray 

Range 100-1,700 m 

In fault contact with, or unconformably overlies(?), Paleozoic rocks, including Horseshoe Bend Formation 

Type section: WSW section across Bloomer Hill in sec. 30, 

T. 21 N., R. 5 E., and continuing from there to SW along 

prominent ridge in sees. 25 and 26, T. 21 N., R. 4 E., and 

toE of Bloomer Hill in sees. 29 and 28, T. 21 N., R. 5 E., 

Berry Creek quadrangle, Butte County, Calif. 

Bluebird Mountain Formation 

1. Late Mississippian (Chesterian) 

2. Idaho (SE) 

3. Skipp, Betty, and others, 1979, Upper Paleozoic carbonate 

bank in east-central Idaho--Snaky Canyon, Bluebird Mountain, 

and Arco Hills Formations, and their paleotectonic signifi- cance: U.S. Geological Survey Bull. 1486, p. 18-20 

4. Quartzose sandstone interbedded with dolomite and limestone 

5. Medium-gray to medium-light-gray, weathers light-brown 

6. 105m, range 7.6-105 m 

7. Very fine grained, mostly thin-bedded, cliff-forming, mostly 

unfossiliferous 

9. Gradationally or unconformably overlies Arco Hills Formation 

or Big Snowy Formation; gradationally underlies Bloom Member 

(Snaky Canyon Formation) 

10. Type section: Exposures on W flank of Gallagher Peak, sees. 

29 and 30, T. 10 N., R. 31 E., Copper Mountain quadrangle, 

Clark County, Idaho. Named for Bluebird Mountain, 5.8 km N 

of type section. 

Blue Lake Rhyolite Me.ber (Mount Belknap Volcanics) 

1. Miocene 

2. Utah (SC) 

3. Steven, T. A., and others, 1979, Revised stratigraphy and 

radiometric ages of volcanic rocks and mineral deposits in 

the Marysvale area, west-central Utah: U.S. Geol. Survey 

Bull. 1469, p. 28-29 

4. Rhyolite 

5. Bleached white 

6. 260 m, range <1-500 m 7. Wedge-shaped body with prominent, contorted flow layering 

g. Overlies unnamed lower tuff member and underlies unnamed 

middle tuff member; units are part of intracaldera facies of 

Mount Belknap Volcanics 

10. Type area: Cliff exposures on flanks of glaciated valley 

adjacent to Blue Lake, Piute County, Utah. 

Blue Mountain Lake Formation 

1. Proterozoic 

2. New York (NE) 

3. McLelland, James, and Isachsen, Yngvar, 1980, Structural 

synthesis of the southern and central Adirondacks--a model 

for the Adirondacks as a whole and plate tectonics interpretations: Geol. Soc. America Bull. (pt. 2, microfiche), v. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

91, no. 2, p. 234-235 

4. Calcite marble with subordinate lenses of amphibolite 

6. Range 300-1,300 m 

1. Coarse-grained 

9. Overlies Lake Durant Formation; underlies Little Moose Mountain Formation; grades laterally into Tomany Mountain Formation to SE 

10. Type locality: Blue Mountain Lake, Blue Mountain quadrangle, Hamilton County, N.Y. 

Blue Sphinx Tuff 

1. Oligocene or Miocene 

2. Nevada (WC) 

3. Ekren, E. B., and others, 1980, Stratigraphy, preliminary 

petrology, and some structural features of Tertiary volcanic 

rocks in the Gabbs Valley and Gillis Ranges, Mineral County, 

Nevada: U.S. Geol. Survey Bull. 1464, p. 33-36 

4. Quartz latite tuff with quartz phenocrysts 

5. Blue or lavender 

6. 30-90 m, range <1-300 m 1. Multiple-flow cooling unit 

9. Overlies tuffaceous and lacustrine sedimentary rocks; underlies lava of Nugent Wash or Nugent Tuff Member (Hu-pwi Rhyodacite) 

10. Type locality: Blue Sphinx monolith, S of Golden Pen Mine, 

sec. 33, T. 11 N., R. 32 E., E flank of Gabbs Valley Range, 

Mineral County, Nev. 

Bluestone Mine Tuff 

1. Oligocene 

2. Nevada (WC) 

3. Proffett, J. M., Jr., and Proffett, B. H., 1976, Stratigraphy of the Tertiary ash-flow tuffs in the Yerington district, Nevada: Nevada Bur. Mines and Geology Rept. 27, p. 

4. 

5. 

6. 

7. 

9. 

10. 

Boonton 

1. 

2. 

3. 

4. 

20-21 

Rhyolitic vitric tuff-breccia interbedded with tuff and 

rhyolitic sandstone and siltstone 

White to pale-buff 

Range 75-270 m Unwelded to poorly welded, crystal-poor, devitrified; easily 

eroded, except for two well-lithified ash-flow tuffs which 

form ridges 

Overlies Singatse Tuff with erosional unconformity; underlies unnamed Oligocene tuff and breccia of Gallagher Pass 

with erosional unconformity 

Type area: Exposures E of Bluestone Mine, NW1/4 sec. 32, 

NE1/4 sec. 31, SE1/4 sec. 30, SW1/4 sec. 29, T. 13 N., 

R. 25 E., Singatse Range, Lyon County, Nev. 

Formation (Newark Supergroup) 

Early Jurassic 

New Jersey (NE) 

Olsen, P. E., 1980, The latest Triassic and Early Jurassic 

formations of the Newark Basin (eastern North America, 

Newark Supergroup)--stratigraphy, structure, and correlation: New Jersey Acad. Sci. Bull., v. 25, no. 2, p. 38 

Clastic deposits composed of siltstone, sandstone, and 

conglomerate; thin beds with pseudomorphs after evaporite 

17 
18 

5. 

6. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

minerals, "Boonton Fish Bed" fossil-fish-bearing siltstone 

Red, brown, gray, black 

>500 m 

Overlies Hook Mountain Basalt; is youngest sedimentary unit 

in Newark basin. Unit was formerly uppermost part of 

Brunswick Formation of Kummel (1897) 

Type section: Exposure along Rockaway River near Boonton, 

Morris County, N.J. 

Boulder Creek Volcanics (Amphitheater Group) 

1. Late Triassic 

2. Alaska (EC) 

3. Stout, J. H., 1976, Geology of the Eureka Creek area, eastcentral Alaska Range: Alaska Div. Geol. and Geophys. 

Surveys Geol. Rept. 46, p. 14-17 

4. Basalt, amygdaloidal basalt 

5. Gray to green 

6. 5,600 m 

1. Occupies core of E-W Amphitheater syncline 

9. Overlies Tangle Lakes Formation (Amphitheater Group); upper 

contact not exposed (top eroded); intruded by gabbro dikes 

related to Fish Lake Complex 

10. Type locality: Low mountains N of Boulder Creek and Sevenmile (Boulder) Lake, Eureka Creek area, Mount Hayes A-5 and 

B-5 quadrangles, Alaska. 

Boxer Formation 

1. Late Cretaceous 

2. California (NW) 

3. Ingersoll, R. V., Rich, E. I., and Dickinson, W. R., 1977, 

Field guide--Great Valley Sequence, Sacramento Valley: 

Geol. Soc. America, Cordilleran Sec., Ann. Mtg., [Guidebook 

8J, p. 28, 31-33 

4. Siltstone, conglomerate, sandstone 

5. Olive-green, dark-gray 

6. 1,600 m; range 1,600-2,900 m 

1. Thin-bedded to laminated siltstone; fine-grained sandstone; 

mixed plutonic and volcanic detritus deposited in deepmarine trough 

8. Salt Creek Conglomerate Member at base 

9. Conformably overlies Lodoga Formation; conformably underlies or intertongues with Cortina Formation 

10. Type section: Low hills adjacent to Boxer Valley and W- . facing slope of Cortina Ridge, Wilbur Springs quadrangle, 

Colusa County, Calif. 

Boyd Gap 

1. 

2. 

3. 

4. 

5. 

6. 

9. 

Formation (Great Smoky Group) 

Late Proterozoic(?) 

Tennessee (SE), North Carolina 

Wiener, L. s., and Merschat, C. E., 1978, Summary of geology 

between the Great Smoky fault at Parksville, Tennessee, and 

basement rocks of the Blue Ridge at Glade Gap, North 

Carolina: Tennessee Div. Geology Rept. Inv. 37, p. 26-27 

Metasedimentary slate, phyllite, metagraywacke, and minor 

metaconglomerate 

Gray 

2,450 m max. 

Underlies informal Buck Bald formation; in contact with 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

informal Farner formation, but stratigraphic relations are uncertain 

10. Type section: Roadcuts along U.S. Highway 64, from 22 to 30 

km E of Parksville, Polk County, Tenn. Named for Boyd Gap. 

Bradbury Creek Granodiorite 

1. Precambrian, middle 

2. Minnesota (C) 

3. Morey, G. B., 1978, Lower and middle Precambrian stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol. Survey Rept. Inv. 21, p. 35-36 

4. Plagioclase-quartz-K-feldspar-hornblende granodiorite 

5. Gray to black 

7. Elliptical pluton 11 km long and 6 km wide, fine- to mediumgrained 

9. Intrudes Hillman Migmatite 

10. Type locality: Outcrops along and N of Bradbury Creek on NS line between sec. 25, T. 41 N., R. 27 W., and sec. 30, 

T. 41 N., R. 26 W., Mille Lacs County, Minn. 

Bradshaw Layered Amphibolite (Baltimore Mafic Complex) 

1. Cambrian(?) 

2. Maryland (NC) 

3. Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the east- ern Maryland Piedmont: Maryland Geol. Survey Rept. Inv. 27, 

p. 16, 28, 30 

4. Interlayered amphibolite and hornblende-quartz-plagioclase 

gneiss, with zones of massive and laminated amphibolite 

9. In thrust-fault contact with Oella Formation (Wissahickon 

Group); underlies Franklinville Gneiss or Perry Hall Gneiss 

in NE-SW synclines; passes into Raspeburg Amphibolite 

(Baltimore Mafic Complex) on NW limb of Perry Hall syncline 

10. Type locality: Outcrops along Little Gunpowder Falls on either side of Old Philadelphia Road (Maryland Route 7) near Bradshaw, White Marsh quadrangle, Baltimore County, Md. 

Braggs Member (Sausbee Formation) 

1. Early Pennsylvanian (Morrowan) 

2. Oklahoma (EC) 

3. Sutherland, P. K., and Henry, T. W., 1977, Carbonate platform facies and new stratigraphic nomenclature of the 

Morrowan Series (Lower and Middle Pennsylvanian), northeastern Oklahoma: Geol. Soc. America Bull., v. 88, no. 3, 

p. 429-431 

4. Limestone interbedded with shale; sandstone in lower part 

6. 31.4 m, range 12.8-53.3 m 

7. Skeletal calcarenite, fossiliferous 

9. Unconformably overlies Pitkin Limestone; conformably underlies and interfingers with Brewer Bend Limestone Member 

(Sausbee Formation) 

10. Type section: Measured Section 1, W bluff of Arkansas 

River, 9-183 m S from W end of Webbers Falls Lock and Dam, 

SW1/4SW1/4SE1/4 sec. 34, T. 13 N., R. 20 E., and Measured 

Section 3, 0.5 km NW of MS 1 along river bluff, 

S1/2NW1/4SW1/4 sec. 34, T. 13 N., R. 20 E., 11 km S of town 

of Braggs, Muskogee County, Okla. Probably named for 

19 
20 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

exposures on Braggs Mountain, bluff on E side of Arkansas 

River near town of Braggs. 

Bramblett Formation 

1. Pleistocene 

2. Texas (WC) 

3. Akersten, W. A., 1970, Red Light local fauna (Blancan) of 

the Love Formation, southeastern Hudspeth County, Texas: 

Texas Memorial Mus. Bull. 20, p. 4, 8 

4. Calcareous clay, silt, sand, gravel 

5. Green, yellow, brown 

6. 23 m 

7. Fine-grained, lenticular, bedded, salty closed-basin 

deposit; vertebrate fossils 

9. Lower contact not known; conformably underlies Love Formation; in fault contact with Early Cretaceous sedimentary 

rocks 

10. Type section: Section BR-1, 1.2 km NNW of John D. Bramblett 

ranch house and 0.4 km NE of county road to ranch, Hudspeth 

County, Tex. 

Branchville Formation (Buffalo Wallow Group) 

1. Late Mississippian (Chesterian) 

2. Indiana (SC) 

3. Gray, H. H., 1978, Buffalo Wallow Group--upper Chesterian 

(Mississippian) of southern Indiana: Indiana Geol. Survey 

Occasional Paper 25, p. 8-10 

4. Shale with limestone beds 

6. 26 m, range 21-32 m 8. Vienna Limestone Member at base, Leopold Limestone Member at 

top 

9. Conformably overlies Tar Springs Formation; conformably 

underlies Tobinsport Formation 

10. Type section: Branchville Section, SE1/4 sec. 14, T. 4 S., 

R. 2 W., Perry County, Ind. Named for settlement of Branchville near headwaters of Oil Creek. 

Branchville Member (Epler Formation) 

1. Early Ordovician 

2. New Jersey (NC) 

3. Markewicz, F. J., and Dalton, Richard, 1977, Stratigraphy 

and applied geology of the lower Paleozoic carbonates in 

northwestern New Jersey--Field Conference of Pennsylvania 

Geologists, 42d, Stroudsburg, 1977, Guidebook: [Harrisburg, 

Pennsylvania Geol. Survey] p. 21 

4. Dolomite with chert and shale interbeds 

5. Gray, weathers reddish brown to buff 

6. 45 m, range 45-94 m 

7. Fine- to coarse-grained, medium- to massive-bedded, laminated; oolites, cryptozoa 

9. Overlies Hope Member (Rickenbach Formation); underlies Big 

Springs Member (Epler Formation) 

10. Type section: Not stated. A measured section including 

this unit extends for about 1.6 km westward from abandoned 

Lehigh ·and New England Railroad right-of-way, 1200 m S of 

New Jersey Route 206 near Branchville, Sussex County, N.J. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Brewer Bend Lilllestone Member (Sausbee Formation) 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Bridger 

1 • 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Early Pennsylvanian (Morrowan) 

Oklahoma (EC) 

Sutherland, P. K., and Henry, T. W., 1977, Carbonate platform facies and new stratigraphic nomenelature of the 

Morrowan Series (Lower and Middle Pennsylvanian), northeastern Oklahoma: Geol. Soc. America Bull., v. 88, no. 3, 

p. 431-432 

Limestone interbedded with minor shale 

Light-gray 

8.7 m, range 1.2-12.6 m 

Algal calcarenite (algal wackestone and mudstone), thin- to 

medium-bedded, nodular, fossiliferous, cliff-forming 

Conformably overlies Braggs Member (Sausbee Formation); 

unconformably underlies McCully Formation 

Type section: Measured Section 1, W bluff of Arkansas 

River, 9-183 m S from W end of Webbers Falls Lock and Dam, 

SW1/4SW1/4SE1/4 sec. 34, T. 13 N., R. 20 E., and Measured 

Section 3, 0.5 km NW of MS 1 along river bluff, 

S 1 /2NW1 /4SW1 /4 sec. 34, T. 13 N., R. 20 E., Muskogee ·County, 

Okla. Derivation of name not stated. 

Peak Quartzite (Libby Creek Group) 

Early Proterozoic 

Wyoming (SC) 

Divis, A. F,, 1976, Geology and geochemistry of Sierra Madre 

Range, Wyoming: Colorado School Mines Quart., v. 71, no. 3, 

p. 26 

Phyllitic, feldspathic, and pure orthoquartzite; interbedded, in lower 1000 m, with biotite-chlorite schist, 

conglomeratic quartzite, and phyllite 

White to tan 

>2,600 m 

Slabby to massive, cross-bedded 

Conformably overlies Cow Creek Conglomerate; conformably 

underlies Copper Creek Conglomerate; lower unit (1000 m) 

lithologically similar to Heart Formation (Libby Creek 

Group) in Medicine Bow Range 

Type area: Exposures in cirques in area of Bridger Peak, 

T. 14 N., R. 86 W., Sierra Madre Range, Carbon County, Wyo. 

Bruce Creek Limestone 

1. Miocene, middle 

2. Florida (NW) 

3. Schmidt, Walter, and Clark, M. W., 1980, Geology of Bay 

County, Florida: Florida Bur. Geology Bull. 57, p. 38-41 

4. Argillaceous, sandy limestone 

5. Pale bluish-green, white, yellow-gray 

6. 0.6 m, range <1-91 m 7. Moderately indurated, granular, fossiliferous, mostly subsurface 

9. Unconformably overlies Chipola Formation; unconformably 

underlies Intracoastal Formation or Jackson Bluff Formation 

10. Type locality: Exposures downstream from county road bridge 

over Bruce Creek, N1/2 sec. 2, T. 1 N., R. 18 W., Walton 

County, Fla. 

21 
22 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Bruin Lillestone Member (Kamishak Formation) 

1. Late Triassic 

2. Alaska (C) 

3. Detterman, R. L., and Reed, B. L., 1980, Stratigraphy, 

structure, and economic geology of the Iliamna quadrangle, 

Alaska: U.S. Geol. Survey Bull. 1368-B, p. B11-B14 

4. Limestone with calcareous siltstone and banded chert beds 

5. Gray, black, green 

6. >610 m 

1. Highly crumpled beds, fossil fragments, reeflike bioherm; 

chert forms prominent cliffs 

9. Overlies Cottonwood Bay Greenstone; underlies unnamed middle 

member of Kamishak Formation 

10. Type locality: Exposures on peninsula on S side of Bruin 

Bay, which opens into Kamishak Bay, Iliamna quadrangle, 

Alaska Peninsula, Alaska. 

Buckland 

1. 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

Formation 

Early Jurassic 

Virginia (NE) 

Lindholm, R. C., 1979, Geologic history and stratigraphy of 

the Triassic-Jurassic Culpeper Basin, ·virginia: Geol. Soc. 

America Bull. (pts. 1 and 2), v. 90, no. 11, p. 996-997 

(pt. 1, summary); p. 1724-1725 (pt. 2, microfiche) 

Basalt flows, interbedded with sandstone, mudstone, and 

shale 

1, 670 m 

Lacustrine beds 

Overlies Bull Run Formation; underlies Waterfall Formation 

Type locality: Exposures along U.S. Highway 29-211 near 

Buckland, Culpeper basin, Prince William County, Va. 

Buford Member (Saddle Mountains Basalt) 

1. Miocene, middle 

2. Oregon (NE), Washington 

3. Swanson, D. A., and others, 1979, Revisions in stratigraphic 

nomenclature of the Columbia River Basalt Group: U.S. Geol. 

Survey Bull. 1457-G, p. G50-G51 

4. Plagioclase- and olivine-phyric basalt 

6. Range 20-30 m 1. Fine- to medium-grained flow 

9. Younger than Elephant Mountain Member; overlies sedimentary 

deposits; upper contact not stated 

10. Type locality: Quarry onE side of Oregon Highway 3, 7.5 km 

NNE of Flora, NE1/4NE1/4 sec. 2, T. 5 N., R. 44 E., Flora 

quadrangle, Wallowa County, Oreg. Named for Buford Creek, 

which heads N of Flora. 

Bugle Member (Keating Formation) 

1. Early Mississippian 

2. New Mexico (SW), Arizona 

3. Armstrong, A. K., and Mamet, B. L., 1978, The Bugle and 

Witch Members of the Keating Formation, Escabrosa Group, and 

the Mississippian nomenclature in the Big Hatchet Mountains, 

Hidalgo County, New Mexico: U.S. Geol. Survey Bull. 1457-A, 

p. A92-A93 

4. Limestone composed of bryozoan-echinoderm to ooid packstone 

and wackestone and argillaceous crinoidal-bryozoan packstone 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

6. 75 m 

1. Massive-bedded, fossiliferous 

9. Unconformably overlies Box Member (Percha Shale); underlies 

Witch Member (Keating Formation) 

10. Type section: E1/2 sec. 30, T. 29 s., R. 15 W., NE side of 

Big Hatchet Mountains, Hidalgo County, N. Mex. Named for 

Bugle Ridge, Big Hatchet quadrangle. 

Bullfrog Member (Crater Flat Tuff) 

1. Miocene 

2. Nevada (SC) 

3. Byers, F. M., Jr., and others, 1976, Volcanic suites and 

related cauldrons of Timber Mountain-Oasis Valley caldera 

complex, southern Nevada: U.S. Geol. Survey Prof. Paper 

919, p. 10-11, 14 

4. Ash-flow tuff 

5. Brown and glassy to light-yellowish-gray 

6. 280 m, range 15-280 m 

1. Glassy, phenocrysts, single cooling unit 

9. Conformably overlies bedded ash-fall tuff which overlies 

Redrock Valley Tuff; underlies Prow Pass Member (Crater Flat 

Tuff) 

10. Type locality: Exposures on Bullfrog Mountain just N of 

original Bullfrog Mine, Bullfrog quadrangle, Nye County, 

Nev. 

Bullfrog 

1. 

2. 

3. 

4. 

6. 

7. 

8. 

9. 

10. 

Bullion 

1. 

2. 

3. 

4. 

5. 

6. 

9. 

10. 

Member (Lakedale Drift) 

Pleistocene 

Washington (C) 

Porter, S. C., 1976, Pleistocene glaciation in the southern 

part of the North Cascade Range, Washington: Geol. Soc. 

America Bull., v. 87, no. 1, p. 70 

Till, gravel 

>80 m, range 25-80 m Moraines, outwash 

Till and outwash facies 

Overlies Indian John Member (Kittitas Drift); underlies 

Ronald Member (Lakedale Drift) 

Type locality: Borrow pit beside S bank of Cle Elum River, 

NE1/4SW1/4 sec. 19, T. 20 N., R. 15 E., Kittitas County, 

Wash. Named for Bullfrog Pond, 2 km downstream. 

Creek Formation (Fort Union Group) 

Paleocene 

North Dakota (SW), Montana, South Dakota 

Clayton, Lee, and others, 1977, The Slope (Paleocene) and 

Bullion Creek (Paleocene) Formations of North Dakota: North 

Dakota Geol. Survey Rept. Inv. 59, p. 10-12 

Alternating beds of clay, silt, sand, and lignite 

Light-yellow; red in burned areas 

100 m, range 50-200 m 

Unconformably overlies Slope Formation; conformably underlies Sentinel Butte Formation (all in Fort Union Group) 

Type section: Red Hills section, SW1/4 sec. 27, SE1/4 

sec. 28, NE1/4 sec. 33, NW1/4 sec. 34, T. 137 N., R. 103 W., 

Golden Valley County, N. Oak. Named for Bullion Creek, 5 km 

N of type section. 

23 
24 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Burlington Fol'llation 

Bush 

1. pre-Silurian (late Precambrian? to Ordovician?) 

2. Massachusetts (C) 

3. Bell, K. G., and Alvord, D. c., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 188-189, 203, app. 1 (in pocket) 

4. Gneiss, quartzite, amphibolite, metamorphosed boulder 

conglomerate 

5. White, pale-gray, dark with white pin-stripe 

6. 300 m 

7. Relict sedimentary structures 

9. Overlies Greenleaf Mountain Formation and Middlesex Fells 

10. 

Bay 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

Volcanic Complex; underlies Marlboro Formation 

Type locality: NW slope of Greenleaf Mountain, NW Lexington 

quadrangle, Middlesex County, Mass. 

Dolostone (Engadine Group) 

Middle Silurian (Niagaran) 

Michigan (EC) 

Johnson, A.M., and others, 1979, The Maple Block knoll reef 

in the Bush Bay Dolostone (Silurian, Engadine Group), 

Northern Peninsula of Michigan: Michigan Univ. Mus. Paleontology Papers on Paleontology, no. 20, p. 14-18 

Dolostone 

Gray, buff, white 

38 m Organic reefs and interreefal facies 

Prentiss Creek Member, Swede Road Member, McKay Bay Member 

Overlies Rapson Creek Dolostone (Engadine Group); lies at 

surface or unconformably(?) underlies Pointe aux Chenes 

Formation (Salina Group) 

Type area: Comprises type localities of its members, in E 

half of Mackinac County, Mich. Named for Bush Bay, which 

opens into Lake Huron SE of Cedarville. 

Byers Canyon Formation 

1. Triassic 

2. Nevada (WC) 

3. Speed, R. c., 1978, Basinal terrane of the early Mesozoic 

marine province of the western Great Basin, in Howell and 

McDougall, eds., Mesozoic paleogeography of the western 

United States: Society of Economic Paleontologists and 

Mineralogists, Pacific Section, Pacific Coast Paleogeography 

Symposium 2, p. 237-252 

4. Pelitic mudstone and laminite with minor limestone, sandstone, and conglomerate 

6. >500 m 9. OVerlies undifferentiated Triassic rocks; underlies Dyer 

Canyon Formation, all in the Clan Alpine sequence 

10. Composite type section: Clan Alpine Mountains, !at 39°45' · N., long 117°45' W., Churchill County, Nev. Named for Byers 

Canyon. 

Cain Formation (Salina Group) 

1. Late(?) Silurian 

2. Michigan (EC) 

3. Briggs, L. I., and others, 1980, Transition from open marine 

to evaporite deposition in the Silurian Michigan basin, in 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Nissenbaum, A., ed., Hypersaline brines and evaporitic 

environments (Developments in Sedimentology, V. 28): 

Amsterdam, Elsevier Sci. Pub. Co., p. 253-270 

4. Limestone, mudstone, carbonate-anhydrite varvite, halite 

salt 

6. 10 m 

7. Starved basin and marine evaporite deposits 

8. Three unnamed members: euxenic limestone; ostracode 

laminite (mudstone); halite-varvite (lower carbonateanhydrite varvite and upper halite) 

9. Conformably overlies Lockport Formation (Niagara Group); 

underlies informal Salina A-1 salt, or A-1 evaporite, unit 

of Salina Group 

10. Type section: Getty Oil Co.-Charles A. Cain et al, No. 1-21 

well, depth-interval 1512-1522 m, SW1/4SW1/4SE1/4 sec. 21, 

T. 31 N., R. 4 E., Montmorency County, Mich. 

Calabasas Fo~ation (Topanga Group) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E22-E24 

4. Sandstone with interbedded silty shale and sedimentary 

breccia 

6. 1,200 m 

7. Medium- to thick-bedded, medium- to coarse-grained, graded 

bedding, locally diatomaceous or phosphatic, fossiliferous 

8. Dry Canyon Sandstone, Escondido Canyon Shale, Latigo Canyon 

Breccia, Newell Sandstone, and Mesa Peak Breccia Members 

(these recognized only in upper plate of Malibu detachment 

fault, EC Point Dume and WC Malibu Beach quadrangles); and 

Stokes Canyon Breccia Member (in Stokes Canyon area, where 

Calabasas is otherwise undivided) 

9. Unconformably overlies or intertongues with Conejo Volcanics 

(Topanga Group) or, locally, overlies Topanga Canyon Formation (Topanga Group); unconformably underlies Modelo 

Formation 

10. Type locality: Exposures in Stokes Canyon, sec. 3, T. 1 S., 

R. 17 W., 3 km W of Calabasas Peak, Santa Monica Mountains, 

NC Malibu Beach quadrangle, Los Angeles County, Calif. 

Califon 

1 • 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

Member (Leithsville Formation) 

Early Cambrian 

New Jersey (NC) 

Markewicz, F. J., and Dalton, Richard, 1977, Stratigraphy 

and applied geology of the lower Paleozoic carbonates in 

northwestern New Jersey--Field Conference of Pennsylvania 

Geologists, 42d, Stroudsburg, 1977, Guidebook: [Harrisburg, 

Pennsylvania Geol. Survey] p. 10-12 , 

Dolomite 

Gray, greenish-gray, weathers buff 

30 m, range 12-46 m 

Lower part: stylolitic, ruditic, megacrystalline, fossiliferous; upper part: fine-grained to cryptogranular 

Overlies Hardyston Formation; underlies Hamburg Member 

(Leithsville Formati~n) 

25 
26 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Type section: Abandoned quarry on E side of New Jersey 

Route 518, 2 km N of Califon, Hunterdon County, N.J. 

Calmar Bentonite Bed (Rivoli Member of Dunleith Formation)/(Loves 

Park Member of Dunleith Formation, in Illinois only) 

1. Middle Ordovician 

2. Iowa (NE), Illinois, Minnesota 

3. Willman, H. B., and Kolata, D. R., 1978, The Platteville and 

Galena Groups in northern Illinois: Illinois Geol. Survey 

Circ. 502, p. 49 

4. Bentonite clay 

6. 0.05 m 

9. In type section, overlies and underlies limestone units of 

Rivoli Member 

10. Type section: Engineers Old Cut Section, stream diversion 

channel, 2.4 km W of Decorah, SE1/4NE1/4 sec. 18, T. 98 N., 

R. 8 W., Winneshiek County, Iowa. Named for town of Calmar, 

14.5 km S of type section. 

Camels Butte Member (Golden Valley Formation) 

1. Eocene 

2. North Dakota (WC) 

3. Hickey, L. J., 1977, Stratigraphy and paleobotany of the 

Golden Valley Formation (early Tertiary) of western North 

Dakota: Geol. Soc. America Mem. 150, p. 28-34 

4. Montmorillonitic claystone, micaceous siltstone and sandstone, chert, conglomerate, lignite 

5. Yellowish-gray to yellow-orange 

6. 25.4 m 7. Plant fossils; channel and interchannel-facies deposits; 

forms gentle, vegetated slopes 

9. Conformably overlies Bear Den Member (Golden Valley Formation); unconformably underlies White River Group 

10. Type section: Section 14117, Camels Butte, 14.5 km N of 

Dickinson, SE1/4SE1/4 sec. 27, T. 141 N., R. 96 W., Dunn 

County, N. Dak. 

Campbell 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Lake Formation (Deep Lake Group) 

Early Proterozoic 

Wyoming (SE) 

Karlstrom, K. E., and Houston, R. S., 1979, Stratigraphy and 

uranium potential of Early Proterozoic metasedimentary rocks 

in the Medicine Bow Mountains, Wyoming: Wyoming Geol. 

Survey Rept. Inv. 13, p. 15-16, 43 

Arkosic paraconglomerate, quartz-rich phyllite, phyllitic 

quartzite 

Black to dark-gray 

65 m 

Widespread deposits of possible glacial origin 

Gradationally overlies Lindsey Quartzite; underlies Cascade 

Quartzite 

Type section: 1.8 km SW of Campbell Lake, SW1/4SNE1/4 

sec. 4, T. 15 N., R. 80 W., Medicine Bow Mountains, Carbon 

County, Wyo. 

campground Member (Sheep Crossing Formation) 

1. Miocene, middle and late 

2. Arizona (EC) 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

3. Merrill, R. K., and Pewe, T. L., 1977, Late Cenozoic geology 

of the White Mountains, Arizona: Arizona Bur. Geology and 

Mineral Technology Spec. Paper 1, p. 17-18 

4. Gravelly sand diamicton 

5. Brown 

6. 3m 

7. Poorly sorted, with cobbles and boulders from lavas of Mount 

Baldy volcano, debris flows deposited in colluvial fans, 

weathers to deep soil 

9. Overlies Marshall Butte ~ember (Sheep Crossing Formation); 

underlies younger basaltic cinders and lava flows 

10. Type section: Railroad cut 700 m NE of Sheep Crossing, near 

old Sheep Crossing Campground, immediately SE of West Fork 

of Little Colorado River, Apache County, Ariz. 

Candelaria Junetion Tuff 

1. Oligocene, late 

2. Nevada (WC) 

3. Speed, R. c., and Cogbill, A. H., 

of the Candelaria region, Nevada: 

Part II, v. 90, no. 2, p. 456-493 

Pumiceous ash-flow tuff 

Pink to reddish-brown 

100 m 

1979, Cenozoic volcanism 

Geol. Soc. America Bull., 

4. 

5. 

6. 

7. Basal zone of poorly compacted glassy tuff overlain by 

strongly compacted tuff with columnar joints, moderately 

compacted stony tuff, and glassy uncompacted tuff 

10. Type locality: North-flowing canyon ·2.15 km S. 15° W. of 

Candelaria Junction, Candelarla Hills, Mineral County, Nev. 

Candland Shale Meaber (Orr Formation) 

1. Late Cambrian 

2. Utah (WC) 

3. Hintze, L. F., and Palmer, A. R., 1976, Upper Cambrian Orr 

Formation--its subdivisions and correlatives in western 

Utah: U.S. Geol. Survey Bull. 1405-G, p. G5-G6, G13-G15 

4. Limestone (calcisiltite, calcarenite), shale 

5. Gray 

6. 125.6 m, range 50-125.6 m 1. Fossiliferous, forms broad benches and slopes 

9. Conformably overlies Big Horse Limestone Member; conformably 

underlies Johns Wash Limestone Member 

10. Type section: NE side of Orr Ridge, along ridge between 

Little Horse Canyon and Big Horse Canyon, NE1/4 sec. 33, 

T. 18 S., R. 13 W., House Range, Notch Peak quadrangle, 

Millard County, Utah. Named for exposures at mouth of Candland Canyon which drains S side of Orr Ridge, 3 km S of type 

section. 

Carpenters Creek Tuff Member (Makah Formation) 

1. Eocene, late 

2. Washington (NW) 

3. Snavely, P. D., Jr., and others, 1980, Makah Formation--a 

deep-marginal-basin sequence of late Eocene and Oligocene 

age in the northwestern Olympic Peninsula, Washington: U.S. 

Geol. Survey Prof. Paper 1162-B, p. 12-13 

4. Calcified and silicified tuff interbedded with siltstone 

5. Light-yellowish-gray 

27 
28 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

1 m 

7 thin water-laid tuff beds, ledge-forming 

Overlies and underlies unnamed strata in lower part of Makah 

Formation 

Type section: Exposures in Carpenters Creek, tributary of 

Sekiu River, NW1/4NW1/4 sec. 17, T. 32 N., R. 13 W., Clallam 

County, Wash. 

Carrigain 

1. 

2. 

3. 

Syenite Porphyry (White Mountain Plutonic-Volcanic Series) 

Jurassic and Cretaceous(?) 

New Hampshire (C) 

Henderson, D. M., and others, 1977, Geology of the Crawford 

Notch quadrangle, New Hampshire: Concord, New Hampshire 

Dept. Resources and Econ. Devel., p. 9 

Feldspar-quartz-ferrohastingsite porphyry with feldspar 

phenocrysts 

4. 

5. 

7. 

9. 

10. 

Gray, white to pink phenocrysts 

Medium-grained; unit forms part of huge cauldron-subsidence 

structure 

In steep intrusive contact with Moat Volcanics, Mount 

Osceola Granite, and Conway Granite (all of White Mountain 

Plutonic-Volcanic Series), but age interrelations not known 

Type area: Mount Carrigain, Crawford Notch quadrangle, 

Grafton County, N.H. 

Carroll Gneiss Member (James Run Formation) 

1. Cambrian(?) 

2. Maryland (NC) 

3. Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the 

eastern Maryland Piedmont: Maryland Geol. Survey Rept. 

Inv. 27, p. 13-15 

4. Biotite-quartz-plagioclase gneiss 

7. Fine- to medium-grained 

9. Overlies(?) or in thrust-fault contact with Hollofield 

Layered Ultramafite (Baltimore Mafic Complex) in E-W anticline; interfingers with Druid Hill Amphibolite Member 

(James Run Formation); underlies Relay Gneiss Member (James 

Run Formation) or Jones Falls Schist in NE-SW syncline 

10. Type locality: Outcrops along unnamed tributary that flows 

through W end of Carroll Park into Gwynns Falls, Baltimore 

City, Baltimore County, Md. 

Cascade Quartzite (Deep Lake Group) 

1. Early Proterozoic 

2. Wyoming (SE) 

3. Karlstrom, K. E., and Houston, R. S., 1979, Stratigraphy and 

uranium potential of Early Proterozoic metasedimentary rocks 

in the Medicine Bow Mountains, Wyoming: Wyoming Geol. 

Survey Rept. Inv. 13, p. 16-19, 43-44 

4. Quartzite, quartzarenite with black chert pebbles, pebble 

arkose 

6. 1,450 m 

7. Crossbedded, resistant, with extensive outcrops; fluvial 

deposits 

9. Overlies Campbell Lake Formation (with gradational contact 

at type section), or overlies Lindsey Quartzite; unconformably underlies Vagner Formation 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

10. Type section: NW1/4 sec. 4, T. 16 N., R. 80 W., Medicine 

Bow Mountains, Carbon County, Wyo. Named for exposures near 

Cascade Lake, sec. 35, T. 17 N., R. 80 W. 

Cave Branch Bed (Newman Limestone) 

1. Late Mississippian 

2. Kentucky (EC) 

3. Dever, G. R., Jr., 1980, Stratigraphic relationships in the 

lower and middle Newman Limestone (Mississippian), eastcentral and northeastern Kentucky: Kentucky Geol. Survey, 

ser. 11, Thesis Ser. 1, p. 44-45, 48-49 

4. Shale 

5. Dark-green to greenish-gray 

6. 0.75 m, range 0.15-1.15 m 7. Platy to bladed, clayey, contains abundant detrital quartz 

(silt to very fine sand) 

9. Overlies informal Paoli-Beaver Bend Limestone member (at 

type section) or St. Louis Limestone Member; underlies 

informal Reelsville-Beech Creek Limestone member 

10. Type section: S side of valley of Cave Branch in roadcut 

along Kentucky Highway 1274, 0.5 km S of Licking River, 

Menifee County, Ky. Named for Cave Branch, a tributary of 

Licking River, NE Menifee and NW Morgan Counties. 

Cave Mountain Formation 

1. Triassic 

2. Washington (NC) 

3. Rinehart, C. D., and Fox, K. F., Jr., 1976, Bedrock geology 

of the Conconully quadrangle, Okanogan County, Washington: 

u.s. Geol. Survey Bull. 1402, p. 9-16 

4. Carbonate-rich metasedimentary and metavolcanic rocks 

5. Dark-gray, white to yellowish-gray 

6. 1,300 m 7. Thinly laminated to massive, fine- to coarse-grained; marine 

(slate and metalimestone member contains fossils); over- turned folds 

8. Informal members metalimestone, metasiltstone, metadolomite 

and metalimestone, slate and metalimestone, and basaltic 

metavolcanic members 

9. Overlies, with probable unconformity, Anarchist Group; 

conformably underlies Triassic metamorphic complex of 

Conconully 

10. Type locality: Exposures in dissected S and SE slopes of 

Cave Mountain, sees. 17, 18, 19, and 20, T. 35 N., R. 26 E., 

Conconully quadrangle, Okanogan County, Wash. 

Cedar Mountain Conglomerate Member (Bull Run Formation) 

1. Late Triassic 

2. Virginia (C) 

3. Lindholm, R. C., 1979, Geologic history and stratigraphy of 

the Triassic-Jurassic Culpeper Basin, Virginia: Geol. Soc. 

America Bull. (pts. 1 and 2), v. 90, no. 11, p. 996 (pt. 1, 

summary); p. 1722-1723 (pt. 2, microfiche) 

4. Greenstone pebble to boulder conglomerate 

5. Red matrix (fresh); gray matrix (metamorphosed) 

6. Range 240-1,400 m 1. Clasts derived from Catoctin Formation 

9. In normal-fault contact with older rocks of Blue Ridge along 

29 
30 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

W border fault 

Type locality: Exposures on Cedar Mountain, 14 km SW of 

Culpeper, Culpeper basin, Culpeper County, Va. 

Cedar River Formation 

1. Proterozoic 

2. New York (NE) 

3. McLelland, James, and Isachsen, Yngvar, 1980, Structural 

synthesis of the southern and central Adirondacks--a model 

for the Adirondacks as a whole and plate tectonics interpretations: Geol. Soc. America Bull. (pt. 2, microfiche), 

v. 91, no. 2, p. 231-233 

4. Calcite marble with subordinate lenses of amphibolite, 

quartzite, and sillimanitic garnet-biotite gneiss 

6. Range 100-300 m 7. Medium- to coarse-grained 

9. Overlies basal quartzofeldspathic gneiss; underlies Lake 

Durant Formation; grades into Sacandaga Formation to SE 

10. Type locality: Small gorge along Cedar River, SSE of Sugarloaf Mountain, sw Blue Mountain quadrangle, Hamilton County, 

N.Y. 

Ceja Member (Santa Fe Formation) 

1. Pliocene 

2. New Mexico (C) 

3. Kelley, V. C., 1977, Geology of Albuquerque Basin, New 

Mexico: New Mexico Bur. Mines and Mineral Resources 

Mem. 33, p. 18-20 

4. Sandstone, conglomerate, mudstone 

5. Buff, gray 

6. 64.3 m 

7. Sandstone: thin- to medium-bedded, medium- to coarse- grained; conglomerate: thick-bedded, containing subrounded 

to angular pebbles to large boulders 

9. Overlies informal middle red member, which is main body of 

Santa Fe Formation; underlies informal Ortiz gravel (Pleistocene) 

10. Type section: Exposure along S side of El Rincon, a box 

canyon in W slope of Ceja Mesa, 19 km W of Albuquerque, 

NE1/4SE1/4 sec. 19, T. 10 N., R. 1 E., Bernalillo County, 

N. Mex. 

Cejita Member (Tesuque Formation) 

1. Miocene, middle 

2. New Mexico (NC) 3. Manley, Kim, 1977, Geologic map of the northeastern part of 

the Espanola Basin, New Mexico: u.s. Geol. Survey Misc. 

Field Studies Map MF-877 

4. Conglomerate with interbedded sand 

5. Grayish-brown 

6. Range 1.5->140 m 7. Well-sorted, coarse conglomerate, coarse- to fine-grained 

sand 

9. Overlies lower Miocene unnamed eolian sand of Santa Fe 

Group; interfingers to SE with main part of Tesuque Formation (Santa Fe Group); locally unconformably underlies late 

Pliocene(?) surface gravels 

10. Type section: Location of clast count Cj 12, T. 22 N., 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

R. 10 E., unsurveyed land grant, long 105 °53' 19" W., lat 

36°08'1811 N., Trampas quadrangle, Rio Arriba County, 

N. Mex. Named for exposures underlying and S of Mesa de la 

Cejita. 

Charcoal Ovens Tuff 

1. Oligocene 

2. Nevada (EC) 

3. Hose, R. K., and Blake, M. C., Jr., 1976, Geology and 

mineral resources of White Pine County, Nevada--Pt. 1, Geology: Nevada Bur. Mines and Geology Bull. 85, p. 19-20 

4. Tuff 

6. 130 m 1. Crystal-rich ash-flow, three cooling units; contains visible 

crystals of honey-yellow sphene 

9. Overlies Sheep Pass Formation or Permian strata; underlies 

Windous Butte Formation 

10. Type section: Quarry, SW1/4NW1/4 sec. 36, T. 14 N., 

R. 63 E., 300-450 m SW of ovens in Ward Charcoal Ovens State 

Park, E side of southern part of Egan Range, White Pine 

County, Nev. 

Chattahoochee Palisades Quartzite (Sandy Springs Group) 

1. Precambrian, late(?) and (or) Paleozoic, early(?) 

2. Georgia (NW) 

3. Higgins, M. W., and McConnell, K. I., 1978, The Sandy 

Springs Group and related rocks in the Georgia Piedmont--

nomenclature and stratigraphy: U.S. Geol. Survey Bull. 

1457-A, p. A103 (Also published in: Georgia Geol. Survey 

Bull. 93, p. 52-53, 1978) 

4. Quartzite interlayered with feldspathic quartzite and muscovite schist 

5. White, yellowish, bluish 

6. 100 m 

1. Sugary to vitreous, massive, cliff-forming 

9. Overlies in sharp contact (unconformably?) Powers Ferry 

Formation; gradationally underlies Factory Shoals Formation 

10. Type area: Palisades of Chattahoochee River in Chattahoochee Palisades State Park, Sandy Springs quadrangle, 

Fulton County, Ga. 

Chilikadrotna Greenstone 

1. Late Silurian 

2. Alaska (C) 

3. Bundtzen, T. K., Gilbert, W. G., and Blodgett, R. B., 1979, 

The Chilikadrotna Greenstone, an Upper Silurian metavolcanic 

sequence in the central Lake Clark quadrangle, Alaska: 

Alaska Div. Geol. and Geophys. Surveys Geol. Rept. 61, 

p. 31-35 

4. Metamorphosed basalt (greenstone), hematite-rich basalt, and 

andesite, with interbedded limestone lenses and volcaniclastic sedimentary rocks 

5. Olive-gray to dark-green, weathers brown to maroon 

7. Greenstone massive, ridge-forming; limestone fossiliferous 

9. In probable high-angle fault contact on all sides with Upper 

Jurassic sedimentary and volcanic rocks 

10. Type area: Upper Chilikadrotna River area, Lake Clark [C-4, 

C-5] quadrangle, Alaska. 

31 
32 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Chill Lakes Till 

1. Holocene 

2. Wyoming (NC) 

3. Nelson, R. S., 1977, Glacial deposits of 

quadrangle, Bighorn Mountains, Wyoming: 

v. 10, no. 1, p. 18 

Cobble and boulder till in sand matrix 

Pinkish-gray, weathers light gray 

6 m 

Loose, bouldery; end and ground moraines 

the Lake Angeline 

Earth Sci. Bull., 

4. 

50 

6. 

7. 

9. Overlies informal Lake Lame Deer till; underlies Lake 

Angeline Till 

10. Type locality: Moraine surrounding Chill Lakes, sees. 33 

and 34, T. 50 N., R. 85 W., Bighorn Mountains, Johnson 

County, Wyo. 

Chisum Quarry Member (McCully Formation) 

1. Middle Pennsylvanian (Morrowan) 

2. Oklahoma (EC) 

3. Sutherland, P. K., and Henry, T. W., 1977, Carbonate platform facies and new stratigraphic nomenclature of the 

Morrowan Series (Lower and Middle Pennsylvanian), northeastern Oklahoma: Geol. Soc. America Bull., v. 88, no. 3, 

p. 433-434 

4. Limestone interbedded with minor shale 

5. Weathers reddish brown 

6. 6.6 m, range 1.5-11 m 

7. Grainstone and packstone, fossiliferous 

9. Unconformably overlies Sausbee Formation; conformably 

underlies and interfingers with informal shale "A" member 

(McCully Formation) 

10. Type section: Measured Section 1, W bluff of Arkansas 

River, 9 to 183 m S from W end of Webbers Falls Lock and 

Dam, SW1/4SW1/4SE1/4 sec. 34, T. 13 N., R. 20 E., and 

Measured Section 3, 0.5 km NW of MS 1 along river bluff, 

S1/2NW1/4SW1/4 sec. 34, T. 13 N., R. 20 E., Muskogee County, 

Okla. 

Ciniza Lake Beds (Monitor Butte Member of Chinle Formation) 

1. Late Triassic 

2. New Mexico (NW) 

3. Ash, S. R., 1978, Stratigraphy of the Ciniza Lake Beds and 

related strata, Chap. 1 in Ash, S. R., ed., Geology, paleontology, and paleoecology-c)f a Late Triassic lake, western 

New Mexico: Brigham Young Univ. Geology Studies, v. 25, pt. 

2, p. 1-14 

4. Shale, mudstone 

5. Gray, greenish-gray 

6. 2.2 m 

7. Shale: fissile but without regular bedding, fossiliferous; 

mudstone: basal thin layer, structureless 

9. Entirely within Monitor Butte Member: overlies flat-lying 

conglomerate or steeply dipping beds; gradationally underlies mudstone of main body 

10. Type section: Locality FW6 in Eastern Wash, 490 m E of New 

Mexico Highway 400 and 2.4 km S of Fort Wingate Post Office, 

Zuni Mountains, McKinley County, N. Hex. Named for Ciniza 

Station on Santa Fe Railroad, 11 km NE of Fort Wingate. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Circle Park Till 

1. Pleistocene 

2. Wyoming (NC) 

3. Nelson, R. s., 1977, Glacial.deposits o~the Lake Angeline 

quadrangle, Bighorn Mountains, Wyoming: Earth Sci. Bull., 

v . 1 0 , no . 1 , p. 1 6 

4. Cobble and boulder till in sand matrix 

5. Light-gray, weathers light yellowish brown 

6. 90 m 

7. Compact; terminal and ground moraines 

9. Overlies Precambrian crystalline complex; underlies Sherd 

Lake Till 

10. Type locality: Moraine W of Circle Park Campground, SW1/4 

sec. 20, T. 50 N., R. 84 W., Bighorn Mountains, Hunter Mesa 

quadrangle, Johnson County, Wyo. 

Claremont 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Manor Member (Eastover Formation) 

Miocene, late (Tortonian) 

Virginia (SE), Maryland 

Ward, L. W., and Blackwelder, B. W., 1980, Stratigraphic 

revision of upper Miocene and lower Pliocene beds of the 

Chesapeake Group, middle Atlantic Coastal Plain: U.S. Geol. 

Survey Bull. 1482-D, p. D12-D19 

Silty and clayey sand, clay 

Greenish-gray, weathers tan 

9 m, range 9'-24 m 

Poorly sorted, coarse- to fine-grained, beds fining upward 

Unconformably overlies St. Marys Formation or, to s, progressively older sediments; unconformably underlies Cobham 

Bay Member (Eastover Formation) 

Type section: Exposures 1.3 km below mouth of Sunken Meadow 

Creek, R bank of James River, Surry County, Va. Named for 

exposures along James River below Upper Chippokes Creek near 

Claremont Manor. 

Cleofas Andesite 

1. Eocene, late 

2. New Mexico (SC) 

3. Seager, W. R., Kottlowski, F. E., and Hawley, J. W., 1976, 

Geology of Dona Ana Mountains, New Mexico: New Mexico Bur. 

Mines and Mineral Resources Circ. 147, p. 14-15 

4. Andesite porphyry 

5. Tan, purple 

1. Massive, fine-grained 

9. Probably intrusive into Palm Park Formation; unconformably 

underlies Oligocene volcanic rocks (Dona Ana Rhyolite or 

unnamed younger cauldron fill of Dona Ana cauldron) 

10. Type locality: Exposures near Cleofas well in Cleofas 

Canyon, SE1/4NE1/4 sec. 22, T. 21 s., R. 1 E., Dona Ana 

Mountains, Dona Ana County, N. Mex. 

Coal Canyon Formation 

1. Paleocene and Eocene(?) 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E8-E9 

33 
34 

4. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Sandstone, pebbly sandstone, pebble conglomerate, siltstone 

with pods of algal limestone 

335 m; range 335-450 m 

Cliff-forming, fossiliferous 

Disconformably(?) overlies Tuna Canyon Formation or, locally, conformably overlies intervening Simi(?) Conglomerate; 

underlies Llajas(?) Formation 

Type locality: Carbon (formerly Coal) Canyon, S1/2 sec. 22 

and sec. 27, T. 1 s., R. 17 W., Santa Monica Mountains, SE 

Malibu Beach quadrangle, Los Angeles County, Calif. 

Cobham Bay Member (Eastover Formation) 

1. Miocene, late (Tortonian) 

2. Virginia (SE), Maryland, North Carolina 

3. Ward, L. W., and Blackwelder, B. W., 1980, Stratigraphic 

revision of upper Miocene and lower Pliocene beds of the 

Chesapeake Group, middle Atlantic Coastal Plain: U.S. Geol. 

Survey Bull. 1482-D, p. D19-D28 

4. Shelly sand 

5. Tan 

6. 3.7 m, range 1-12m 

1. Well-sorted, fine-grained, fossiliferous 

9. Unconformably overlies Claremont Manor Member (Eastover 

Formation); unconformably underlies Sunken Meadow Member 

(Yorktown Formation) 

10. Type section: Exposures 0.8 km below Cobham Wharf, R bank 

of James River, Surry County, Va. Named for exposures along 

James River at Cobham Bay. 

Cold Creek Member (Topanga Canyon Formation) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E17 

4. Sandstone 

6. 707 m 

7. Medium-grained, bedded, silty to pebbly, fossiliferous, 

marine 

9. Conformably overlies Fernwood Member (Topanga Canyon Formation); unconformably underlies Conejo Volcanics (Topanga 

Group) or, locally, Calabasas Formation (Topanga Group) 

10. Type locality: Cold Creek-Old Topanga Canyon area, SW1/4 sec. 35, T. 1 N., R. 17 W., Santa Monica Mountains, NE 

corner Malibu Beach quadrangle, Los Angeles County, Calif. 

Cold Spring Gneiss 

1. [Ordovician(?) or Silurian(?)] 

2. Maryland (NC) 

3. Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the eastern Maryland Piedmont: Maryland Geol. Survey Rept. Inv. 27, 

p. 13, 15 

4. Biotite-muscovite-quartz-feldspar gneiss or schistose gneiss 

9. Intrudes Hollofield Layered Ultramafite and Mount Washington 

Amphibolite (Baltimore Mafic Complex) and Druid Hill Amphibolite Member (James Run Formation) 
10. 

Coleman 

1 • 

2. 

3. 

4. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Type locality: Outcrops in Cold Spring Park, along Eflowing tributary of Jones Falls, Baltimore City, Baltimore 

County, Md. 

River Formation (Coweeta Group) 

Precambrian, late(?) [Late Proterozoic(?)] 

Georgia (NC), North Carolina 

Hatcher, R. D., Jr., 1979, The Coweeta Group and Coweeta 

syncline--major features of the North Carolina-Georgia Blue 

Ridge: Southeastern Geology, v. 21, no. 1, p. 21-23 

Metasandstone, metaarkose, and quartz-feldspar gneiss with 

interlayers of pelitic schist 

Medium-grained, foliated, metasandstone thinly laminated or "pinstriped" 

Overlies Persimmon Creek Formation; underlies Ridgepole 

Mountain Formation 

Type area: Exposures along headwaters of Coleman River, 

Dillard quadrangle, Rabun County, Ga. 

Coabs canyon Dola.ite MeBber (Hanson Creek Formation) 

1. Silurian 

2. Nevada (C) 

3. Ross, R. J., Jr., Nolan, T. B., and Harris, A. G., 1979, The 

Upper Ordovician and Silurian Hanson Creek Formation of 

central Nevada: U.S. Geol. Survey Prof. Paper 1126-C, p. C5 

4. Dolomite with conglomerate and chert beds 

5. Dark-gray 

7. Fossiliferous (pentamerid brachiopods); all outcrops of 

Hanson Formation are tectonically disturbed 

9. Conformably overlies light-gray dolomite of middle (limestone and dolomite) member of Hanson Creek Formation; conformably underlies, or in thrust-fault contact with, Lone 

Mountain Dolomite 

10. Type locality: S side of Combs Canyon, NE1/4 sec. 31, 

T. 18 N., R. 52 E., Bellevue Peak quadrangle, Eureka County, 

Nev. 

CoBfort Member (Castle Hayne Formation) 

1. Eocene, middle (Claibornian) 

2. North Carolina (EC) 

3. Ward, L. W., Lawrence, D. R., and Blackwelder, B. W., 1978, 

Stratigraphic revision of the middle Eocene, Oligocene, and 

lower Miocene--Atlantic Coastal Plain of North Carolina: 

U.S. Geol. Survey Bull. 1457-F, p. F8-F9 

4. Calcirudite and calcarenite (limestone) with minor quartz, 

glauconite, and phosphate 

5. Gray to cream-colored 

6. 2 m, range 2-10 m 

7. Fossiliferous 

9. Unconformably overlies New Hanover Member (Castle Hayne 

Formation); conformably underlies Spring Garden Member 

(Castle Hayne Formation), or unconformably underlies Duplin 

Formation or River Bend Formation 

10. Type locality: N. C. Lime Excavating Co. quarry, 6.4 km W 

of Comfort, just N of North Carolina Route 41, Jones County, 

N.C. 

35 
36 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Conant Creek Tuff 

1. Pliocene 

2. Wyoming (NW), Idaho 

3. Christiansen, R. L., and Love, J. D., 1978, The Pliocene 

Conant Creek Tuff in the northern part of the Teton Range 

and Jackson Hole, Wyoming: U.S. Geol. Survey Bull. 1435-C, 

p. C1-C9 

4. Rhyolitic ash-flow tuff 

5. Gray to purplish-gray 

6. 125 m, range <1-125 m 

7. Welded, sparse phenocrysts 

9. Unconformably overlies Hominy Peak Formation (at type 

section), or Teewinot or Bivouac Formation; unconformably 

underlies Huckleberry Ridge Tuff (Yellowstone Group) 

10. Type section: Exposure on N side of South Boone Creek where 

steep-sided tributary enters main creek, NE1/4SW1/4 sec. 5, 

T. 47 N., R. 117 W., Grassy Lake Reservoir quadrangle, Teton 

County, Wyo. Named for nearby Conant Creek. 

Condrey Mountain Schist 

1. 

2. 

3. 

4. 

5. 

7. 

9. 

10. 

Congress 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Late Jurassic 

California (NW), Oregon 

Hotz, P. E., 1979, Regional metamorphism in the Condrey 

Mountain quadrangle, north-central Klamath Mountains, California: U.S. Geol. Survey Prof. Paper 1086, p. 2-9 

Quartz-muscovite schist, actinolite-chlorite schist 

Gray to brownish-gray 

Fine-grained, alternating light and dark laminae 

Bordered on E and W by Paleozoic and Triassic(?) unnamed 

rocks of amphibolite metamorphic facies structurally overlying and thrust over Condrey Mountain Schist 

Type locality: Exposures on S side of Klamath River between 

Dona and McKinney Creeks, sees. 8 and 9, T. 46 N., R. 9 W., 

NC Klamath Mountains, Siskiyou County, Calif. Named for 

Condrey Mountain, sec. 11, T. 47 N., R. 10 W. 

Canyon Formation (Star Peak Group) 

Middle and Late Triassic (Ladinian and Karnian) 

Nevada (NW) 

Nichols, K. M., and Silberling, N.J., 1977, Stratigraphy 

and depositional history of the Star Peak Group (Triassic), 

northwestern Nevada: Geol. Soc. America Spec. Paper 178,· 

p. 51-54 

Limestone 

Gray 

120 m, range 120-300 m 

Coarse-grained, massive, cliff-forming, platform-margin 

deposits 

Overlies unnamed upper member of Prida Formation (Star Peak 

Group); underlies sugary secondary dolomite under Panther 

Canyon or Smelser Pass Members of Augusta Mountain Formation 

(Star Peak Group) 

Type section: Head of Congress Canyon, W1/2 sec. 16, 

T. 30 N., R. 34 E., N Humboldt Range, Pershing County, Nev. 

Conover Bentonite Bed (Rivoli Member of Dunleith Formation)/(Loves 

Park Member of Dunleith Formation, in Illinois only) 

1. Middle Ordovician 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

2. Iowa (NE), Illinois 

3. Willman, H. B., and Kolata, D. R., 1978, The Platteville and 

Galena Groups in northern Illinois: Illinois Geol. Survey 

Circ. 502, p. 49 

4. Bentonite 

6. 0.025 m 

9. In type section, topmost unit of Rivoli Member; underlies 

Sherwood Member (Dunleith Formation) 

10. Engineers Old Cut Section, stream diversion channel, 2.4 km 

W of Decorah, SE1/4NE1/4 sec. 18, T. 98 N., R. 8 W., Winneshiek County, Iowa. Named for town of Conover, 11.2 km SW 

of type section. 

Coon Valley Member (Jordan Formation) 

1. Early Ordovician 

2. Wisconsin (SW), Iowa, Minnesota 

3. Odom, I. E., and Ostrom, M. E., 1978, Lithostratigraphy, 

petrology, sedimentology, and depositional environments of 

the Jordan Formation near Madison, Wisconsin: Soc. Econ. 

Paleontologists and Mineralogists, Great Lakes Sec., 

8th Ann. Mtg., Guidebook 3, p. 26-27, 31-34, 43 

4. Dolomitic sandstone, sandy dolostone, and sandstone with 

interbedded shale, chert, oolites, and algal structures 

6. 11 m 

7. Fine- to medium-grained, poorly sorted 

9. Overlies Van Oser Member or Sunset Point Member (Jordan 

Formation); underlies Oneota Formation 

10. Type section: S side of U.S. Highway 14, 3.2 km W of town 

of Coon Valley, NW1/4NE1/4 sec. 11, T. 14 N., R. 6 W., 

Vernon County, Wis. 

Copper Basin Formation 

1. Miocene, early 

2. California (SE), Arizona 

3. Davis, G. A., and others, 1980, Mylonitization and detachment faulting in the Whipple-Buckskin-Rawhide Mountains 

terrane, southeastern California and western Arizona: Geol. 

Soc. America Mem. 153, p. 95 

4. Sandstone, conglomerate, and siltstone with interbedded 

andesitic(?) volcanic rocks 

5. Red 

6. >750 m 

7. Cross-bedding, ripple marks, mudcracks; upper unit in 

allochthonous upper-plate assemblage separated from lowerplate assemblage by subhorizontal detachment fault 

9. Unconformably overlies Gene Canyon Formation on E and S margins of Whipple Mountains, but overlies upper-plate crystalline basement rocks in C part of mountains; unconformably 

underlies Osborne Wash Formation 

10. Type section: Not stated. Probably named for Copper Basin 

in EC Whipple Mountains, San Bernardino County, Calif. 

Copper Creek Conglomerate (Libby Creek Group) 

1. Early Proterozoic 

2. Wyoming (SC) 

3. Divis, A. F., 1976, Geology and geochemistry of Sierra Madre 

Range, Wyoming: Colorado School Mines Quart., v. 71, no. 3, 

p. 26-27 

37 
38 

4. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Conglomerate composed of granitic clasts in schist matrix 

Range 75-100 m 

Angular to subrounded clasts widely dispersed through finegrained matrix 

Conformably overlies Bridger Peak Quartzite; conformably 

underlies Quartzite Peak Quartzite 

Type area: Outcrops at confluence of North Fork of Miner 

and Copper Creeks at boundary of sees. 27 and 28, T. 14 N., 

R. 84 W., Carbon County, Wyo. 

Copper Lake Formation 

1. Paleocene(?) and Eocene 

2. Alaska (C) 

3. Detterman, R. L., and Reed, B. L., 1980, Stratigraphy, 

structure, and economic geology of the Iliamna quadrangle, 

Alaska: U.S. Geol. Survey Bull. 1368-B, p. B45-B48 

4. Conglomerate, sandstone, siltstone 

5. Gray 

6. Lower conglomerate member: 91 m; sandstone and siltstone 

member: 503 m; upper conglomerate member: 975 m 

8. Informal lower conglomerate member, sandstone and siltstone 

member, and upper conglomerate member 

9. Nonconformably overlies Middle Jurassic quartz diorite 

pluton or unconformably overlies Kakhonak Complex; uncon- formably underlies Tertiary volcanic rocks 

10. Type section: Composite of type sections of members. Lower 

conglomerate member: E end of ridge 2.5 km S. 45° E. of 

outlet of Upper Copper Lake; sandstone and siltstone 

member: E slope of peak 2432, 1.6 km S of Wend of Boot 

Lake; upper conglomerate member: ravine cutting E face of 

ridge between Fog and Kakhonak Lakes; all between Upper 

Copper Lake and Sid Larson Bay, SE of Lake Iliamna, Iliamna 

quadrangle, Alaska Peninsula, Alaska. 

Copperopolis Latite (Tintic Mountain Volcanic Group) 

1. Oligocene, middle 

2. Utah (C) 

3. Morris, H. T., and Lovering, T. S., 1979, General geology 

and mines of the East Tintic mining district, Utah and Juab 

Counties, Utah: U.S. Geol. Survey Prof. Paper 1024, 

p. 36-38 

4. Latite agglomerate and spatter breccia, tuff, and flow 

5. Lower member: dark-green; middle member: gray-green; upper 

member: black, reddish-brown 

6. >120 m 7. Lower member: coarse-grained, massive; middle member: 

fine- to medium-grained, layered; upper member: finegrained 

8. Informal lower agglomerate and spatter breccia member, 

middle tuff member, and upper flow member 

9. Unconformably overlies Packard Quartz Latite; unconformably 

underlies Latite Ridge Latite (Tintic Mountain Volcanic 

Group) 

10. Type locality: Exposures in Copperopolis Canyon, sees. 31, 

32, and 33, T. 11 S., R. 2 W., WC part of East Tintic Mountains, 16 km SW of East Tintic mining district, Juab County, 

Utah. 
Corkscrew 

1 • 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Swamp Formation (Naples Bay Group) 

Early Cretaceous (Comanchean) 

Florida (SE) 

Winston, G. D., 1976, Six proposed formations in the undefined portion of the Lower Cretaceous section in south Florida: Gulf Coast Assoc. Geol. Socs. Trans., v. 26, p. 70 

Limestone with thin anhydrite and microcrystalline dolomite 

beds 

137 m 

Dense micritic limestone at base, thin anhydrite bed at top 

Overlies Rookery Bay Formation (Naples Bay Group); underlies 

Pine Key Formation 

Type section: Humble No. 1 Collier Corp. well, depthinterval 2623-2760 m, sec. 27, T. 50S., R. 26 E., Collier 

County, Fla. Named for Corkscrew Swamp, 24 km N of type 

well. 

Cortina Formation 

1. Late Cretaceous 

2. California (NW) 

3. Ingersoll, R. V., Rich, E. I., and Dickinson, W. R., 1977, 

Field guide--Great Valley Sequence, Sacramento Valley: 

Geol. Soc. America, Cordilleran Sec., Ann. Mtg., [Guidebook 

8J, ~· 28, 33-35 

4. Sandstone, siltstone, mudstone 

5. Olive, gray 

6. 2,900 m 

1. Thin- to thick-bedded; coarse-grained; mixed plutonic and 

volcanic detritus deposited in deep-marine trough 

8. Venado Sandstone Member at base; Sites Sandstone Member 

9. Conformably overlies or intertongues with Boxer Formation; 

underlies Rumsey Formation 

10. Type section: Exposures on Cortina Ridge, Wilbur Springs 

quadrangle, Colusa County, Calif. 

Cottonwood Bay Greenstone 

1. Late Triassic 

2. Alaska (C) 

3. Detterman, R. L., and Reed, B. L., 1980, Stratigraphy, 

structure, and economic geology of the Iliamna quadrangle, 

Alaska: U.S. Geol. Survey Bull. 1368-B, p. B9-B11 

4. Mafic volcanic rocks altered to hornfels and chloritic 

greenschist 

5. Dark-green, gray 

6. >600 m 

7. Original porphyritic texture mostly altered to hornfelsic 

and granoblastic 

9. Locally so intensely altered as to be part of Kakhonak 

Complex; locally cannot be distinguished from Talkeetna 

Formation; underlies Bruin Limestone Member (Kamishak Formation) 

10. Type locality: Exposures on S shore near head of Cottonwood 

Bay, Cook Inlet, Iliamna quadrangle, Alaska Peninsula, 

Alaska. 

Council Sandstone Member (Norton Formation) 

1. Middle Pennsylvanian 

2. Virginia (SW) 

39 
40 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Miller, R. L., and Meissner, C. R., Jr., 1977, Geologic map 

of the Big A Mountain quadrangle, Buchanan and Russell Counties, Virginia: U.S. Geol. Survey Geol. Quad. Map GQ-1350 

Sandstone 

Light-gray 

24 m, range <1-49 m 

Medium- to coarse-grained, conglomeratic, thick-bedded, 

cross-bedded, wedges out in many places 

Overlies Tiller coal bed; underlies Jawbone coal bed 

Type locality: Exposure in bluff and roadcut of Virginia 

Highway 80 directly beneath Council Elementary School. 

Named for town of Council in NC part of Big A Mountain quadrangle, Buchanan County, Va. 

Cove Mountain Member (Flagstaff Limestone) 

1. Paleocene, late, and (or) Eocene, early 

2. Utah (C) 

3. Stanley, K. 0., and Collinson, J. W., 1979, Depositional 

history of Paleocene-lower Eocene Flagstaff Limestone and 

coeval rocks, central Utah: Am. Assoc. Petroleum Geologists 

Bull., v. 63, no. 3, p. 316-318 

4. Dolomicrite, mudstone, gypsum 

5. White, pinkish-gray, yellowish-brown 

6. 185 m 7. Sparsely fossiliferous; represents low stand of Lake Flagstaff 

8. 

9. 

10. 

Cow Creek 

1 • 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

Eight informal units, I through P 

Overlies Ferron Mountain Member; underlies Musinia Peak 

Member 

Type locality: S side of Cove Mountain, NW1/4 sec. 2, 

T. 19 S., R. 4 E., and SW1/4 sec. 35, T. 18 S., R. 4 E., 

Wasatch Plateau, Sanpete County, Utah. 

Conglomerate (Libby Creek Group) 

Early Proterozoic 

Wyoming (SC) 

Divis, A. F., 1976, Geology and geochemistry of Sierra Madre 

Range, Wyoming: Colorado School Mines Quart., v. 71, no. 3, 

p. 22-26 

Conglomerate composed of granitic, mafic, and quartzite 

clasts in quartzite to amphibolite matrix 

>300 m 

Coarse, well-rounded clasts, spheroids to severely stretched 

ellipsoids 

Lithologically similar to Headquarters Schist (Libby Creek 

Group) in Medicine Bow Range; basal Formation in Libby Creek 

Group in Sierra Madre Range; overlies Green Mountain Formation with structural unconformity; conformably underlies 

Bridger Peak Quartzite (Libby Creek Group) 

Type area: Outcrops on S wall of Cow Creek valley, 

T. 14 N., R. 85 W., Sierra Madre Range, Carbon County, Wyo. 

Coweeta .Group 

1. Precambrian, late(?) [Late Proterozoic(?)] 

2. North Carolina (WC), Georgia 

3. Hatcher, R. D., Jr., 1979, The Coweeta Group and Coweeta 

syncline--major features of the North Carolina-Georgia Blue 

Ridge: Southeastern Geology, v. 21, no. 1, p. 17-29 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

4. Feldspar-quartz-biotite gneiss, metasandstone, quartzite, 

schist 

6. Range 2,000-4,000 m 

1. Occupies syncline resulting from polyphase deformation 

8. Persimmon Creek Gneiss, Coleman River Formation, Ridgepole 

Mountain Formation 

9. Overlies Tallulah Falls Formation; upper contact not 

observed (top eroded) 

10. Type area: Upper reaches of Coweeta Creek in Coweeta Hydrologic Laboratory, S of Franklin, Macon County, N.C. 

Cowen Member (Grand Detour Formation) 

1. Middle Ordovician 

2. Illinois (NC) 

3. Willman, H. B., and Kolata, D. R., 1978, The Platteville and 

Galena Groups in northern Illinois: Illinois Geol. Survey 

Circ. 502, p. 30 

4. Dolomite to shaly dolomite 

6. 2.3 m, range 1.8-5.4 m 

1. Thin- to medium-bedded 

9. Overlies Mifflin Formation; underlies Stillman Member (Grand 

Detour Formation) 

10. Type section: Brookville Northwest Section, quarry on N 

side of ravine NE of U.S. Highway 52, NE1/4SE1/4NW1/4 

sec. 21, T. 24 N., R. 7 E., Carroll County; 1.6 km NW of 

Brookville, Ogle County, Ill. Named for Cowen School, 3.2 

km SW of type section. 

Cow Hollow Bed (Laney Member of Green River Formation) 

1. Eocene 

2. Wyoming (SW) 

3. Sullivan, Raymond, 1980, A stratigraphic evaluation of the 

Eocene rocks of southwestern Wyoming: Wyoming Geol. Survey 

Rept. Inv. 20, p. 30 

4. Shale, marlstone, sandstone, siltstone 

5. Buff-weathering 

6. Range 9-15 m 1. Lacustrine deposits 

9. On W margin of Green River Basin, overlies and intertongues 

with Whiskey Butte Bed (Bridger Formation); underlies main 

body of Bridger; merges with main body of Laney Member to S 

10. Type locality: Exposures along Cow Hollow Creek, T. 21 N., 

R. 113 W., Cow Hollow quadrangle, Lincoln County, Wyo. 

Crater Flat Tuff 

1. Miocene 

2. Nevada (SC) 

3. Byers, F. M., Jr., and others, 1976, Volcanic suites and 

related cauldrons of Timber Mountain-Oasis Valley caldera 

complex, southern Nevada: U.S. Geol. Survey Prof. 

Paper 919, p. 10-11, 14-15 

4. Tuff 

5. Varicolored 

6. 190 m 1. Welded to nonwelded, devitrified, phenocrysts 

8. Bullfrog and Prow Pass Members and local unnamed intercalated breccia, bedded tuff, and ash-flow tuff 

41 

9. Overlies Redrock Valley Tuff; underlies, to S, all construe-
42 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

tiona! lavas of Wahmonie-Salyer volcanic center and rhyolite 

lavas of Calico Hills 

Type locality: Exposed at SE end of unnamed hogback at S 

side of Crater Flat, Bare Mountain quadrangle, Nye County, 

Nev. 

Craven Creek Bed (Laney Member of Green River Formation) 

1. Eocene 

2. Wyoming (SW) 

3. Sullivan, Raymond, 1980, A stratigraphic evaluation of the 

Eocene rocks of southwestern Wyoming: Wyoming Geol. Survey 

Rept. Inv. 20, p. 30 

4. Calcareous silty shale, laminated siltstone, sandstone 

5. Buff 

6. 36 m 

7. Lacustrine deposits 

9. On W margin of Green River Basin, overlies and intertongues 

with Desertion Point Member (Wasatch Formation, underlies 

and intertongues with Whiskey Butte Bed (Bridger Formation); 

merges with main body of Laney Member to S and E 

10. Type locality: Exposures along Craven Creek, N of Hams 

Fork, T. 21 N., R. 114 W., Opal quadrangle, Lincoln County, 

Wyo. 

Cross Member (Santee Limestone) 

1. Eocene, middle (Claibornian) 

2. South Carolina (C) 

3. Ward, L. W., and others, 1979, Stratigraphic revision of 

Eocene, Oligocene and lower Miocene formations of South 

Carolina: South Carolina Geol. Survey Geol. Notes, v. 23, 

no. 1, p. 8-9 

4. Biomicrite (limestone) 

5. Grayish-yellow 

6. 1 m, range 1-41 m 

7. Bryozoan-brachiopod-bivalve biomicrite, deeply burrowed 

9. Unconformably overlies Moultrie Member (Santee Limestone); 

unconformably underlies Raysor Formation at type section, or 

Harleyville Member (Cooper Formation) 

10. Type section: Section at Martin Marietta Co. Berkeley 

quarry, 2.4 km S of Route 6 and Route 59 intersection, 

Chicora 15' quadrangle, Berkeley County, S.C. Named for 

nearby town of Cross. 

Cross Creek Granite 

1. [Early Proterozoic] 

2. Colorado (C) 

3. Tweto, Ogden, and Lovering, T. S., 1977, Geology of the 

Minturn 15-minute quadrangle, Eagle and Summit Counties, 

Colorado: U.S. Geol. Survey Prof. Paper 956, p. 8-12 

4. Granite to granodiorite, typically quartz monzonite 

5. Gray to pinkish-gray 

7. Coarse-grained, gneissic, porphyritic; batholith occupies 

area of 130 sq km 

9. Intrudes enclosing gneiss with concordant and gradational 

contacts; intermixed with closely related diorite and migmatite; unconformably underlies Sawatch Quartzite 

10. Type area: Cross Creek, N end of Sawatch Range, Minturn 

quadrangle, Eagle County, Colo. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Daguao Formation 

1. 

2. 

3. 

4. 

5. 

6. 

1. 

9. 

10. 

Dalmatia 

1 • 

2. 

3. 

4. 

5. 

6. 

1. 

9. 

10. 

Early Cretaceous 

Puerto Rico (EC) 

M'Gonigle, J. W., 1977, The Rio Abajo, Pitahaya, and Daguao 

Formations in eastern Puerto Rico: U.S. Geol. Survey 

Bull. 1435-B, p. B7-B9 

Andesite breccia, lava, volcanic sandstone, and crystal tuff 

Medium-gray to medium-dark-gray 

>1,000 m Massive breccia, cut by fine-grained and porphyritic lava 

dikes; lava flows; two hypabyssal intrusive bodies of breccia representing volcanic necks 

Base not exposed; sharply or gradationally(?) underlies 

Figuera Lava; in intrusive contact with Tertiary(?) plutonic 

rocks 

Type area: E~posures in housing excavations just N of town 

of Daguao at 46,000 N., 231,500 E.; Municipio de Naguabo, 

Naguabo quadrangle, P.R. 

Member (Mahantango Formation) 

Middle Devonian 

Pennsylvania (C) 

Faill, R. T., Hoskins, D. M., and Wells, R. B., 1978, Middle 

Devonian stratigraphy in central Pennsylvania--a revision: 

Pennsylvania Geol. Survey, 4th ser., Gen. Geology Rept. 70, 

p. 11-14, 21-22 

Shale, siltstone, sandstone 

Olive-gray 

>67 m, 90 m max 

Cyclic deposits, coarsening upward; sparsely fossiliferous 

Overlies Turkey Ridge Member; underlies Fisher Ridge Member 

Type section: N wall of third abandoned quarry, counting 

from S, along E side of Penn Central Railroad, 3.2 km S of 

Dalmatia, Northumberland County, Pa. 

Danielson Member (Vaqueros Formation) 

1. Miocene, early 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E12 

4. Mudstone, siltstone 

5. Grayish-black 

1. Very fine grained, thin- to medium-bedded, fossiliferous, 

local biostromes 

9. Overlies Sespe Formation; conformably underlies San Nicholas 

Member (Vaqueros Formation) 

10. Type locality: Exposures on Danielson Ranch, Big Sycamore 

Canyon, Santa Monica Mountains, Newbury Park quadrangle, 

Ventura County, Calif. Reference locality: Exposures in 

upper Trancas Canyon, W Point Dume quadrangle, Los Angeles 

County. 

Day Mountain Member (Seboomook Formation) 

1. Early Devonian 

2. Maine (WC) 

3. Pankiwskyj, K. A., 1979, Bedrock geology of the Kingfield 

43 
44 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

Deer Lake 

1 • 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

and Anson 15' quadrangles, Franklin and Somerset Counties, 

Maine: Maine Geol. Survey Geol. Map Series GM-7, 51 p. 

Metasiltstone, metapelite, graywacke 

Gray 

>1 ,000 m 

Rhythmically bedded 

Granule metaconglomerate and metalimestone submembers 

Gradationally overlies and intertongues with Temple Stream 

Member (Seboomook Formation) 

Type locality: Exposures on ridge and slopes of Day Mountain, SW corner of Kingfield quadrangle, Franklin County, 

Maine. 

Complex 

Precambrian 

Minnesota (NC) 

Berkley, J. L., and Himmelberg, G. R., 1978, Cumulus mineralogy and petrology of the Deer Lake Complex, Itasca County, 

Minnesota: Minnesota Geol. Survey Rept. Inv. 20-A, p. A1-

A18 

Peridotite, clinopyroxenite, gabbro, diorite 

430 m 

Three layered sills, each intruded along upper contact of 

previous one; each magma injection fractionated into 

sequence of ultramafic to dioritic rocks 

Conformably intrudes early Precambrian metabasalt and metasedimentary rocks; cut by middle Precambrian(?) gabbroic 

dikes 

Type locality: NE-trending band 10 km long and 2.5 km wide 

in Tps. 61-62 N., Rs. 24-25 W., 4 km SW of Deer Lake and 6.5 

km NE of Bigfork, Itasca County, Minn. 

Deicke Bentonite Bed (Castlewood Member of Spechts Ferry Formation) 

1. Middle Ordovician 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Dell Tuf'f' 

1. 

2. 

3. 

4. 

Missouri (EC), Illinois, Iowa, Wisconsin 

Willman, H. B., and Kolata, D. R., 1978, The Platteville and 

Galena Groups in northern Illinois: Illinois Geol. Survey 

Circ. 502, p. 43 

Bentonite clay 

Light-gray, alters pink 

0.13 m 

Altered locally to bed of hard monoclinic potash feldspar 

Near or at base of Castlewood Member (Spechts Ferry Formation), which unconformably overlies Quimbys Mill Formation 

Type section: Mincke Section, in S bluff of Meramec River 

along St. Louis-San Francisco Railroad, 0.4 km NE of Mincke 

Siding, center E1/2SE1/4SE1/4 sec. 21, T. 44 N., R. 4 E., 

St. Louis County, Mo. Named for town of Deicke, 3.2 km SW 

of type section. 

Oligocene 

Utah (WC) 

Lindsey, D. A., 1979, Geologic map and cross-sections of 

Tertiary rocks in the Thomas Range and northern Drum Mountains, Juab County, Utah: U.S. Geol. Survey Misc. Inv. Ser. 

Map I-1176 

Rhyolitic ash-flow tuff with crystals of quartz, sanidine, 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

biotite, and plagioclase 

5. Gray to pink 

6. 180 m 

1. Poorly welded to unwelded matrix of devitrified shards and 

pumice 

9. Unconformably overlies Drum Mountains Rhyodacite, or locally 

overlies Oligocene(?) breccia at Spor Mountain or Paleozoic 

rocks; unconformably underlies Spor Mountain Formation 

10. Type locality: The Dell, sees. 23 and 24, T. 12 S., 

R. 12 w., Thomas Range,.Juab County, Utah. 

Del Norte Formation 

1. Early Cretaceous 

2. New Mexico (SC), Texas, Mexico 

3. Strain, W. S., 1976, New formation names in the Cretaceous 

at Cerro de Cristo Rey, Dona Ana County, New Mexico, 

Appendix 2 in Lovejoy, E. M.P., Geology of Cerro de Cristo 

Rey uplirt,-chihuahua and New Mexico: New Mexico Bur. Mines 

and Mineral Resources Mem. 31, p. 77-78 

4. Shale interbedded with sandy limestone and sandstone 

5. Gray, tan 

6. 11.2 m 

1. Fossiliferous, nodular 

8. Informal lower clay member and upper calcareous member 

(equivalent to informal Brick Plant and Refinery members of 

Strain, 1968) 

9. Conformably overlies Finlay Formation; conformably underlies 

Smeltertown Formation 

10. Type section: Outcrops W of kilns at El Paso Brick Company 

plant, NW1/4SW1/4NW1/4 sec. 15, T. 29 S., R. 4 E., Smeltertown quadrangle, Dona Ana County, N. Mex. Named for R!o 

Bravo del Norte, original name of Rio Grande. 

Denham Formation (Mille Lacs Group) 

1. Precambrian, middle 

2. Minnesota (C) 

3. Morey, G. B., 1978, Lower and middle Precambrian stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol. Survey Rept. Inv. 21, p. 15-18 

45 

4. Heterogeneous sequence of arenitic quartz-rich rocks ranging 

from conglomerate to siltstone, with interbedded quartzite, 

dolomite, and metabasalt 

5. Greenish-gray, reddish-gray 

7. Layered 

9. Unconformably overlies McGrath Gneiss; to W, underlies or 

grades laterally into Glen Township Formation (Mille Lacs 

Group), or unconformably underlies Animikie Group 

10. Type locality: Exposures in abandoned river valley 1.6 km 

SE of village of Denham, SE1/4 sec. 25 and NE1/4 sec. 26, 

T. 45 N., R. 21 W., Pine County, Minn. 

Desertion Point Tongue (Wasatch Formation) 

1. Eocene 

2. Wyoming (SW) 

3. Sullivan, Raymond, 1980, A stratigraphic evaluation of the 

Eocene rocks of southwestern Wyoming: Wyoming Geol. Survey 

Rept. Inv. 20, p. 13-15 

4. Siltstone and sandstone with interbeds of marlstone and 
46 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

limestone 

Variegated red 

76 m 

Red- bed fluviatile facies 

On W margin of Green River Basin, overlies and intertongues 

with Wilkins Peak Member (Green River Formation); underlies 

and intertongues with Craven Creek Bed of Laney Member 

(Green River Formation); thins toN and E, passes to S into 

main body of Wasatch Formation along Uinta Mountains front 

Type locality: Near Desertion Point, sec. 26, T. 19 N., 

R. 115 W., and E to Little Muddy Creek, Mulkay Spring quadrangle, Lincoln County, Wyo. 

Desert Range Limestone Member (Carrara Formation) 

1. Middle Cambrian 

2. Nevada (SE), California 

3. Palmer, A. R., and Halley, R. B., 1979, Physical stratigraphy and trilobite biostratigraphy of the Carrara Formation 

(Lower and Middle Cambrian), southern Great Basin: U.S. 

Geol. Survey Prof. Paper 1047, p. 20-21 

4. Argillaceous limestone, with dolomitic partings 

5. Black, orange 

6. 20 m, varies considerably and inconsistently 

1. Thin-bedded, fossiliferous 

9. Overlies Jangle Limestone Member (Carrara Formation); gradationally underlies Bonanza King Formation 

10. Type locality: Exposures at Desert Range, about 64 km NW of 

Las Vegas, Clark County, Nev. 

Devine canyon Ash-now Tu:ff 

1. Miocene, late 

2. Oregon (EC) 

3. Walker, G. W., 1979, Revisions to the 

of Harney Basin, southeastern Oregon: 

Cenozoic stratigraphy 

U.S. Geol. Survey 

4. 

5. 

6. 

7. 

9. 

10. 

Bull. 1475, p. 15-20 

Tuff 

Greenish-gray to light-gray 

30 m 

Densely to moderately welded, crystal-rich, vitric 

Overlies unnamed middle(?) and upper Miocene volcaniclastic 

and sedimentary rocks which overlie Steens Basalt; conformably underlies unnamed tuffaceous sedimentary rocks which 

underlie Prater Creek Ash-flow Tuff; to NE, in Juntura 

Basin, underlies Drewsey Formation 

Type locality: Exposures in Devine Canyon about 1 km NNE of 

its confluence with Poison Creek, along U.S. Highway 395, 

lat 43°44'05" N., long 119° W., Harney County, Oreg. 

Diamond City Clay 

1. Pleistocene 

2. North Carolina (EC) 

3. Susman, K. R., and Heron, S. D., Jr., 1979, Evolution of a 

barrier island, Shackleford Banks, Carteret County, North 

Carolina: Geol. Soc. America Bull., (pt. 1), v. 90, no. 2, 

p. 207-209 

4. Soft silty illite-rich clay interbedded with shell hash in 

sandy clay matrix 

5. Gray 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 47 

6. 6 m 

9. Disconformably overlies informal Core Creek sand (Pleistocene); unconformably underlies informal Outer Banks sand 

(Holocene) 

10. Type locality: Drill hole SH-11, onE end of Shackleford 

Banks, Carteret County, N.C. Named for abandoned whaling 

village on this site. 

Dickeyville Bentonite Bed (Glenhaven Member of Guttenberg Formation) 

1. Middle Ordovician 

2. Wisconsin (SC), Illinois 

3. Willman, H. B., and Kolata, D. R., 1978, The Platteville and 

Galena Groups in northern Illinois: Illinois Geol. Survey 

Circ. 502, p. 45 

4. Bentonite clay 

5. Gray 

6. 0.05 m, range 0.01-0.05 m 9. Overlies and underlies limestone or dolomite units near top 

of Glenhaven Member 

10. Type section: Dickeyville Northwest Section, quarry and 

roadcuts along U.S. Highway 61, 6.5 km NW of Dickeyville, 

NE1/4NE1/4SW1/4 sec. 7 and S1/2NW1/4 sec. 7, T. 2 N., 

R. 2 W., Grant County, Wis. 

Dobys Bluff Tongue (Kosciusko Formation) 

1. Eocene 

2. Mississippi (EC) 

3. Dockery, D. T., III, 1980, The invertebrate macropaleontology of the Clarke County, Mississippi, area: Mississippi 

Bur. Geology Bull. 122, p. 33-41 

4. Sand, carbonaceous clay 

5. Gray, weathers reddish brown 

6. 6 m 

7. Lenticular, marine destructional shelf facies, fossiliferous 

9. Overlies nonfossiliferous sand of Kosciusko Formation; 

unconformably underlies Archusa Marl Member (Cook Mountain 

Formation) 

10. Type section: Exposure at Dobys Bluff, E side of Chickasawhay RiverS of Quitman, NW1/4SW1/4NW1/4 sec. 18, T. 2 N., 

R. 16 E., Clarke County, Miss. 

Domerie Member (Lakedale Drift) 

1. Pleistocene 

2. Washington (C) 

3. Porter, S. C., 1976, Pleistocene glaciation in the southern 

part of the North Cascade Range, Washington: Geol. Soc. 

America Bull., v. 87, no. 1, p. 70-71 

4. Till, gravel 

7. Moraines, outwash 

8. Till and outwash facies 

9. Overlies Ronald Member; underlies Hyak Member 

10. Type locality: Till facies: face of moraine impounding Cle 

Elum Lake at Lakedale, NW1/4SW1/4 sec. 2, T. 20 N., 

R. 14 E.; outwash facies: cut along N bank of Cle Elum 

River E of Domerie Flats, NW1/4SE1/4, sec. 11, T. 20 N., 

R. 14 E., Kittitas County, Wash. Named for Domerie Flats 

bordering Cle Elum Lake. 
48 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Dona Ana Rhyolite 

1. Oligocene 

2. New Mexico (SC) 

3. Seager, W. R., Kottlowski, F. E., and Hawley, J. W., 1976, 

Geology of Dona Ana Mountains, New Mexico: New Mexico Bur. 

Mines and Min. Res. Circ. 147, p. 14-15 

4. Rhyolite ash-flow tuff 

5. Brownish-gray to gray 

6. 760 m 

7. Massive, welded, crudely foliated; main rock unit of Dona 

Ana cauldron 

9. Unconformably overlies Eocene rocks (Palm Park Formation or 

Cleofas Andesite); underlies unnamed volcaniclastic sedimentary rocks and landslide breccias, and associated intrusions 

and flows, of Dona Ana cauldron fill 

10. Type locality: Dona Ana Peak, T. 21 s., R. 1 E., Dona Ana 

County, N. Mex. 

Doswell Formation 

1. Late Triassic 

2. Virginia (EC) 

3. Weems, R. E., 1980, Geology of the Taylorsville basin, 

Hanover County, Virginia: Virginia Div. Mineral Resources 

Pub. 27, p. 24-27 

4. Sandstone, conglomerate, siltstone, with minor shale, coal, 

and limestone 

5. Black to gray, weathers dark red, grayish orange 

6. 1,099 m 

7. Massive, cross-bedded 

8. Stagg Creek, Falling Creek, and Newfound Members 

9. Nonconformably overlies Petersburg Granite; unconformably 

underlies Miocene to Holocene age unconsolidated strata 

10. Type section: Along Stagg Creek, beginning at Hanover Country Club 0.3 km N of Virginia Highway 54 and continuing S to 

contact with Petersburg Granite, Taylorsville basin, Hanover 

Academy quadrangle, Hanover County, Va. Named for village 

of Doswell. 

Double Lakes Formation 

1. Pleistocene (Wisconsinan) 

2. Texas (NC), New Mexico 

3. Reeves, C. c., Jr., 1976, Quaternary stratigraphy and 

geologic history of southern High Plains, Texas and New 

Mexico, in Mahaney, w. C., ed., Quaternary stratigraphy of 

North America: Stroudsburg, Pa., Dowden, Hutchinson and 

Ross, p. 221-222 

4. Clay with epsomite and gypsum crystals 

5. Olive-gray 

6. 8.5 m 

7. Lacustrine basin fill 

9. Lower contact not stated; underlies Tahoka Formation 

10. Type section: Core depth-interval 14.02-22.56 m, Double 

Lakes basin, Lynn County, Tex. 

Drakes Bay Formation 

1. Miocene, late, or Pliocene, early 

2. California (WC) 

3. Galloway, A. J., 1977, Geology of the Point Reyes Peninsula, 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Marin County, California: California Div. Mines and Geology 

Bull. 202, p. 26-34 

4. Basal glauconite-bearing greensand and overlying siltstone 

and mudstone 

5. Green, cream to brown, gray to yellowish 

6. 260 m, range <1->490 m, top eroded 

1. Occupies syncline, W of San Andreas fault zone 9. Unconformably overlies granitic basement rocks, Point Reyes 

Conglomerate, or Monterey Shale; unconformably underlies 

Quaternary sediments 

10. Type section: Drakes Bay sea cliff extending from Drakes 

Estero [SW about 6 km] to granitic outcrop at E end of Point 

Reyes ridge, Marin County, Calif. 

Druid Hill Amphibolite Member (James Run Formation) 

1. Cambrian(?) 

2. Maryland (NC) 

3. Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the eastern Maryland Piedmont: Maryland Geol. Survey Rept. Inv. 27, 

p. 13-15 

4. Amphibolite with interlayered chlorite fels and actinofels 

6. 700 m 1. Fine- to medium-grained, well-foliated 

9. Overlies(?) or in thrust-fault(?) contact with Hollofield 

Layered Ultramafite or Mount Washington Amphibolite (Baltimore Mafic Complex) in E-W anticline; interfingers with 

Carroll Gneiss Member (James Run Formation); underlies Relay 

Gneiss Member (James Run Formation) or Jones Falls Schist in 

NE-SW syncline; intruded by Cold Spring Gneiss 

10. Type locality: Outcrops along streams in Druid Hill Park, 

especially in ravine on E side of Druid Park Drive, 

Baltimore City, Baltimore County, Md. 

Drua Mountains Rhyodacite 

1. Eocene, late 

2. Utah (WC) 

3. Lindsey, D. A., 1979, Geologic map and cross-sections of 

Tertiary rocks in the Thomas Range and northern Drum Mountains, Juab County, Utah: U.S. Geol. Survey Misc. Inv. Ser. 

Map I-1176 

4. Rhyodacite to quartz latite, with plagioclase and pyroxene 

phenocrysts 

5. Black, rusty-weathering 

1. Flows and breccias 

9. Overlies Paleozoic rocks; underlies Mount Laird Tuff, or 

unconformably underlies Joy Tuff, Dell Tuff, or Spor Mountain Formation 

10. Type locality: Exposures in Drum Mountains, sees. 32, 33, 

and 34, T. 14 s., R. 11 W., Juab County, Utah. 

Dry Branch Formation (Barnwell Group) 

1. Eocene, late 

2. Georgia (C) 

3. Huddlestun, P. F., and Hetrick, J. H., 1979, The stratigraphy of the Barnwell Group of Georgia: Georgia Geol. 

Survey Open File Rept. 80-1, p. 17-25, 71-73 

4. Sand, calcareous sand, clay, montmorillonite clay 

49 
50 

6. 

7. 

8. 

9. 

1 0. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Range 9-54 m 

Three distinct but interfingering and intergrading lithofacies recognized as formal members in some areas; fossiliferous 

Twiggs Clay Member, Irwinton Sand Member, Griffins Landing 

Sand Member 

Overlies Clinchfield Formation (Barnwell Group) or Tivola 

Limestone (Ocala Group); conformably underlies Tobacco Road 

Sand (Barnwell Group) 

Type locality: Exposure along railroad cut at highway 

bridge where U.S. Highway 80 passes over Seaboard Coast 

Line, 3.7 km S of community of Dry Branch, Twiggs County, 

Ga. 

Dry Canyon Sandstone Member (Calabasas Formation) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E24 

4. Sandstone, siltstone, dolomitic concretions in siltstone 

6. 686 m 

7. Thin turbidites; broken coarse-grained arkosic arenite 

containing reworked(?) Miocene mollusks 

9. Overlies Ramera Canyon Tongue (Conejo Volcanics); intertongues with Escondido Canyon Shale Member (Calabasas Formation) or Solstice Canyon Tongue (Conejo Volcanics); underlies Newell Sandstone Member (Calabasas Formation) or Malibu 

Bowl Tongue (Conejo Volcanics) 

10. Type area: Dry Canyon, Santa Monica Mountains, WC Malibu 

Beach quadrangle, Los Angeles County, Calif. 

Dtokoah Point Member (Makah Formation) 

1. Eocene, late 

2. Washington (NW) 

3. Snavely, P. D., Jr., and others, 1980, Makah Formation--a 

deep-marginal-basin sequence of late Eocene and Oligocene 

age in the northwestern Olympic Peninsula, Washington: U.S. 

Geol. Survey Prof. Paper 1162-B, p. 9-11 

4. Sandstone, siltstone· 

5. Olive-gray 

6. 65 m 

7. Fine-grained, rib-forming turbidite beds 

9. Gradationally overlies and underlies unnamed strata in lower 

part of Makah Formation, above Baada Point Member and below 

Klachopis Point Member 

10. Type section: Exposures on Dtokoah Point and wave-cut platform, NW1/4SE1/4 sec. 12, T. 33 N., R. 15 W., Strait of Juan 

de Fuca, Clallam County, Wash. 

Dutch Harbor Member (Unalaska Formation) 

1. Miocene, early(?) 

2. Alaska (SC) 

3. Lankford, S. M., and Hill, J. M., 1979, Stratigraphy and 

depositional environment of the Dutch Harbor Member of the 

Unalaska Formation, Unalaska Island, Alaska: U.S. Geol. 

Survey Bull. 1457-B 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

4. Sandstone with interbedded conglomerate 

5. Light- to medium-greenish-gray 

6. 126 m 

1. Very fine to fine-grained, indurated sandstone; rhythmically 

bedded turbidite and debris-flow deposits 

9. Conformably overlies and ·underlies unnamed lower and upper 

aquagene volcanic sequences of Unalaska Formation 

10. Type section: Section measured about 3 km E of village of 

Unalaska, Unalaska Island, Aleutian Islands, .Alaska. 

Dyer Canyon Formation 

1. Triassic 

2. Nevada (WC) 

3. Speed, R. C., 1978, Basinal terrane of the early Mesozoic 

marine province of the western Great Basin, in Howell and 

McDougall, eds., Mesozoic paleogeography of the western 

United States: Soc. Econ. Paleontologists and Mineralogists, Pacific Sec., Pacific Coast Paleogeography Symposium 

2, p. 237-252 

4. Quartzose, detrital mica-rich sandstone with minor pelitic 

mudstone and laminite 

6. 1,200 m 

9. Overlies Byers Canyon Formation; underlies Bernice Formation, all in the Clan Alpine sequence 

10. Composite type section: Clan Alpine Mountains, lat 39°45' 

N., long 117°45' W., Churchill County, Nev. Named for Dyer 

Canyon. 

Dygerts 

1. 

2. 

3. 

4. 

6. 

9. 

10. 

Bentonite Bed (Sinsinawa Member of Wise Lake Formation) 

Middle Ordovician 

Illinois (NW), Iowa, Minnesota 

Willman, H. B., and Kolata, D. R., 1978, The Platteville and 

Galena Groups in northern Illinois: Illinois Geol. Survey 

Circ. 502, p. 52 

Bentonite clay 

0.05 m 

Overlies and underlies dolomite units near middle of Sinsinawa Member 

Type section: Galena Roadcut Section, roadcut on U.S. 

Highway 20 onE side of Galena River, SW1/4SE1/4NE1/4 

sec. 20, T. 28 N., R. 1 E., in Galena, Jo Daviess County, 

Ill. Named for Dygerts Mound, 2.4 km SE of type section. 

Eagle Mountain Member (Paluxy Sand) 

1. Early Cretaceous 

2. Texas (C) 

3. OWen, M. T., 1979, The Paluxy Sand in north-central Texas: 

Baylor Geol. Studies Bull. 36, p. 8, 25-29 

4. Sand, clay 

5. Purple, brown, white 

6. 19 m, range 2-23 m 

1. Cross-bedded, fossiliferous, fluvial and shallow marine 

deposits 

9. Unconformably overlies Georges Creek Member (Paluxy Sand); 

unconformably underlies Walnut Clay 

10. Type locality: Twin Points Resort at E end of Eagle Mountain Lake spillway, Tarrant County, Tex. 

51 
52 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Eagle Mountain Shale Member (Carrara Formation) 

1. Early Cambrian 

2. california (EC), Nevada 

3. Palmer, A. R., and Halley, R. B., 1979, Physical stratigraphy and trilobite biostratigraphy of the Carrara Formation 

(Lower and Middle Cambrian), southern Great Basin: U.S. 

Geol. Survey Prof. Paper 1047, p. 9-13 

4. Silty shale with interbedded terrigenous or carbonate siltand sand-size material 

5. Green to gray-brown 

6. Range <1-59 m 

7. Slope-forming, fossiliferous 

9. Overlies Emigrant Pass Member (Zabriskie Quartzite); 

conformably underlies Thimble Limestone Member (Carrara 

Formation) 

10. Type locality: Exposures on W side of Eagle Mountain, Inyo 

County, Calif. 

Easley Dolerite 

1. Mesozoic 

2. South Carolina (NW) 

3. Snipes, D. S., and Furr, J. E., 1979, Easley Dolerite in the 

South Carolina Piedmont: South Carolina Geol. Survey Geol. 

Notes, v. 23, no. 2, p. 129-145 

4. Dolerite 

5. Dark-gray to black, weathers light brown 

7. Dike 10-100 m wide, 14 km long, fine-grained, jointed 

9. Intrudes Paleozoic metamorphic rocks 

10. Type locality: Lat 34°50'32" N., long 82°30'35" W., 75 m S 

of Southern Railroad and 0.45 km S. 74° W. of trestle over 

Georges Creek, Pickens County, S.C. Named for town of 

Easley, 9.5 km W of type locality. 

Eastover Formation (Chesapeake Group) 

1. Miocene, late (Tortonian) 

2. Virginia (SE), Maryland, North Carolina 

3. Ward, L. W., and Blackwelder, B. W., 1980, Stratigraphic 

revision of upper Miocene and lower Pliocene beds of the 

Chesapeake Group, middle Altantic Coastal Plain: U.S. 

Geol. Survey Bull. 1482-D, p. D8-D28 

4. Silty sand, clay, shelly sand 

5. Greenish-gray, tan 

6. 7 m, range 6-24 m 

7. Fine-grained, fossiliferous 

8. Claremont Manor and Cobham Bay Members 

9. Unconformably overlies St. Marys Formation or, to S, progressively older sediments; unconformably underlies Sunken 

Meadow Member (Yorktown Formation) 

10. Type section: Exposures 0.8 km above Mount Pleasant on R 

bank of James River, 5.1 km E of Eastover, Surry County, Va. 

Echo Shale Member (Carrara Formation) 

1. Early Cambrian 

2. California (EC), Nevada 

3. Palmer, A. R., and Halley, R. B., 1979, Physical stratigraphy and trilobite biostratigraphy of the Carrara Formation 

(Lower and Middle Cambrian), southern Great Basin: U.S. 

Geol. Survey Prof. Paper 1047, p. 13 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 53 

4. Micaceous shale with calcareous intervals or interbedded 

limestone 

·5. Green, brown, orange 

6. Range <1-42 m 

7. Platy, generally unfossiliferous 

9. Overlies Thimble Limestone Member; gradationally underlies 

Gold Ace Limestone Member, or is inseparable from Pyramid 

Shale Member where Gold Ace is absent 

10. Type locality: Exposures at "Narrows" of Echo Canyon, Inyo 

County, Calif. 

Eckler Mountain Mellber (Wanapum Basalt) 

1. Miocene, middle 

2. Washington (SE), Oregon 

3. Swanson, D. A., and others, 1979, Revisions in stratigraphic 

nomenclature of the Columbia River Basalt Group: U.S. Geol. 

Survey Bull. 1457-G, p. G27-G31 

4. Basalt 

6. 20 to 25 m 

7. Coarse- to fine-grained, several flows 

8. Informal basalt of Robinette Mountain, basalt of Dodge, and 

basalt of Shumaker Creek 

9. Disconformably overlies Grande Ronde Basalt; disconformably 

underlies Frenchman Springs Member (Wanapum Basalt) (both 

formations in Yakima Basalt Subgroup of Columbia River 

Basalt Group) 

10. Type locality: On S and SE sides of Eckler Mountain, about 

17 km SE of Dayton, N1/2 sees. 26 and 27, T. 9 N., R. 40 E., 

Eckler Mountain quadrangle, Columbia County, Wash. 

Ecor Rouge Sand 

1. Miocene, late 

2. Alabama (SW) 

3. Isphording, W. C., 1977, Petrology and stratigraphy of the 

Alabama Miocene: Gulf Coast Assoc. Geol. Socs. Trans., v. 27, p. 305-306 

4. Sand, gravelly sand, quartzite gravel 

5. White, reddish-brown 

6. 12 m 

7. Cross-bedded, fluvial marine clastics 

9. Overlies Mobile Clay; underlies Citronelle Formation 

10. Type locality: Ecor Rouge (Sea Cliff), onE shore of Mobile 

Bay near town of Fairhope, Baldwin County, Ala. 

Elkhead Limestone 

1. Middle Cambrian 

2. Idaho (SE) 

3. Trimble, D. E., and Carr, w. J., 1976, Geology of the RockU.S. Geol. 

4. 

5. 

6. 

7. 

9. 

10. 

land and Arbon quadrangles, Power County, Idaho: 

Survey Bull. 1399, p. 12-13 

Limestone, with interbedded shale unit 

Gray 

640 m 

Thin-bedded, ledge-forming, platy, to thick-bedded to massive, oolitic; fossiliferous 

Conformably overlies Gibson Jack Formation; conformably 

underlies Bloomington Formation 

Type locality: Exposures both E and W of Midnight Creek, 
54 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

sees. 7, 8, 17, and 18, T. 8 s., R. 34 E., Arbon quadrangle, 

Power County, Idaho. Named for 'Elkhead Ranch on Midnight 

Creek. 

Elkport 

1 • 

Bentonite Bed (Glenhaven Member of Guttenberg Formation) 

Middle Ordovician 

2. 

3. 

4. 

5. 

6. 

9. 

10. 

Iowa (NE), Illinois, Wisconsin 

Willman, H. B., and Kolata, D. R., 1978, The Platteville and 

Galena Groups in northern Illinois: Illinois Geol. Survey 

Circ. 502, p. 45 

Bentonite clay 

Gray 

0.03 m 

Basal unit of Glenhaven Member; overlies Garnavillo Member 

(Guttenberg Formation) 

Type section: Guttenberg North Section, roadcut on U.S. 

Highway 52, NW of Guttenberg, SW1/4SW1/4 sec. 5, T. 92 N., 

R. 2 W., Clayton County, Iowa. Named for town of Elkport, 

14.5 km SW of type section. 

Elwell Formation 

1. Late Devonian 

2. California (NC) 

3. Durrell, Cordell, and D'Allura, Jad, 1977, Upper Paleozoic 

section in eastern Plumas and Sierra Counties, northern 

Sierra Nevada, California: Geol. Soc. America Bull., v. 88, 

no. 6, p. 846-847 

4. Radiolarian chert interbedded with andesite tuff 

5. Black, gray 

6. 90 m, range 90-300 m 

9. Overlies Sierra Buttes Formation; underlies Taylor Formation 

10. Type area: Along ridge overlooking valley W of Long Lake, 

SE1/4 sec. 12, T. 21 N., R. 11 E., Plumas County, Calif. 

Probably named for Mount Elwell, 0.5 km NW of Long Lake. 

Emigrant Pass Member (Zabriskie Quartzite) 

1. Early Cambrian 

2. California (EC), Nevada 

3. Palmer, A. R., and Halley, R. B., 1979, Physical stratigraphy and trilobite biostratigraphy of the Carrara Formation 

(Lower and Middle Cambrian), southern Great Basin: U.S. 

Geol. Survey Prof. Paper 1047, p. 7-9 

4. Quartzite, sandstone, minor siltstone and phyllitic shale 

5. Maroon, brown, yellow, pale-green, pink, white 

6. Range <1-51 m 

1. Quartzite medium- to coarse-grained, laminated or low-angle 

crossbeds; mudcracks in upper part 

9. As uppermost unit and only formal member, overlies main body 

of Zabriskie Quartzite; underlies Eagle Mountain Shale 

Member (Carrara Formation) 

10. Type locality: Exposures N of Emigrant Pass, NW1 /4 sec. ~.5, 

T. 21 N., R. 8 E., S Nopah Range, Tecopa quadrangle, Inyo 

County, Calif. 

Blllperor Volcanic Colllplex 

1. [Early Proterozoic] 

2. Michigan (NW) 

3. Trent, V. A., 1976, The Emperor Volcanic Complex of the East 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Gogebic Range, Michigan: U.S. Geol. Survey Bull. 1422-A, 

p. A69-A74 

55 

4. Basalt flows, flow-breccias, metagabbro, metadiorite, and 

metadiabase 

5. Dark-gray to greenish-gray 

6. >700 m 

7. Dike swarm, phacoliths, sill, flows; prominent fold, fault, 

and joint formation; superimposed metamorphic grades 

8. Wolf Mountain Creek Formation, youngest and only formally 

named unit 

9. Overlies Palms Formation; underlies Copps Formation 

10. Type locality: Exposures N and W of Kimberly Clark logging 

road, which runs E to NNE through sees. 21, 22, and 15, 

T. 47 N., R. 44 W., Wakefield NE quadrangle, Gogebic County, 

Mich. Named for Emperor Creek, tributary of Little Presque 

Isle River, sees. 14 and 15, T. 47 N., R. 44 W. 

Encampment River Granodiorite 

1. Early Proterozoic 

2. Wyoming (SC) 

3. Divis, A. F., 1976, Geology and geochemistry of Sierra Madre 

Range, Wyoming: Colorado School Mines Quart., v. 71, no. 3, 

p. 30-31 

4. Granodiorite 

7. Well-foliated, medium-grained 

9. Intrudes Green Mountain Formation 

10. Type area: Exposed in gorge of North Fork of Encampment 

River, Sierra Madre Range, Carbon County, Wyo. 

Encinal Member (Topanga Canyon Formation) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E15-E16 

4. Siltstone or silty mudstone with dolomitic concretions 

5. Dark-gray 

6. 430 m 

7. Platy to shaly 

9. Conformably overlies San Nicholas Member (Vaqueros Formation); unconformably underlies Conejo Volcanics (Topanga 

Group) 

10. Type locality: Exposures on Encinal Canyon Road, sees. 21 

and 28, T. 1 s., R. 19 W., lower Encinal Canyon, Santa 

Monica Mountains, Point Dume quadrangle, Los Angeles County, 

Calif. 

Escalante 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

Desert Formation 

Oligocene 

Utah (SW) 

Grant, S. K., 1978, Stratigraphic relations of the Escalante 

Desert Formation near Lund, Utah: Brigham Young Univ. Geol. 

Studies, v. 25, pt. 3, p. 27-30 

Ash-flow tuff with interbedded volcaniclastic rocks 

Pink, brown, lavender 

169 m 

Crystal-poor, lithic-bearing 
56 

8. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Informal lower, middle, and upper members, which include six 

ash-flow beds, A to F. [In Beaver County, NNW of type 

locality, D. R. Campbell (1978) subdivides formation into 

Lamerdorf Tuff Member and Beers Spring Member.] 

Overlies unnamed volcanic conglomerate or informal tuff of 

Frisco; underlies Wah Wah Springs Tuff Member (Needles Range 

Formation) 

Type section: NE flank of hill 6535, sec. 6, T. 32 S., 

R. 14 W., W margin of Escalante Desert, S Wah Wah Mountains, 

Lund quadrangle, Iron County, Utah. 

Escondido Canyon Shale Member (Calabasas Formation) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E24 

4. Siltstone, mudstone, shale, minor interbedded sandstone 

turbidites, dolomitic concretions in siltstone 

6. 276 m 

9. Overlies Ramera Canyon Tongue (Conejo Volcanics); intertongues with Dry Canyon Sandstone Member (Calabasas Formation); underlies Latigo Canyon Breccia Member (Calabasas 

Formation) 

10. Type area: Escondido Canyon, Santa Monica Mountains, EC 

Point Dume quadrangle, Los Angeles County, Calif. 

Esquatzel Member (Saddle Mountains Basalt) 

1. Miocene, middle 

2. Washington (SE) 

3. Swanson, D. A., and others, 1979, Revisions in stratigraphic 

nomenclature of the Columbia River Basalt Group: U.S. Geol. 

Survey Bull. 1457-G, p. G45-G46 

4. Plagioclase- and clinopyroxene-phyric basalt 

6. Range <10-50 m 1. One flow 

9. Unconformably overlies Priest Rapids Member (Wanapum 

Basalt); underlies Pomona Member (Saddle Mountains Basalt) 

10. Type locality: Hillslope on N side of Esquatzel Coulee, 

elevation 223-241 m, NW1/4NW1/4 sec. 25, T. 13 N., R. 30 E., 

1 km N of Mesa, Mesa quadrangle, Franklin County, Wash. 

Eureka Canyon Tuff 

1. Oligocene 

2. Nevada (WC) 

3. Bingler, E. C., 1978, Abandonment of the name Hartford Hill 

Rhyolite Tuff and adoption of new formation names for middle 

Tertiary ash-flow tuffs in the Carson City-Silver City area, 

Nevada: u.s. Geol. Survey Bull. 1457-D, p. D14-D16 

4. Rhyolite tuff 

5. White to pale-gray, lavender, and tan 

6. 130 m, range 130-150 m 1. Vitric, distinct cooling zonation; mostly devitrified, 

weakly welded, with zones of vitrophyre; very uniform in 

primary texture and composition 

9. Disconformably overlies Nine Hills Tuff; disconformably 

underlies younger Tertiary tuffs 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

10. Type section: Exposures in Eureka Canyon, at common boundary between sees. 32 and 33, T. 16 N., R. 21 E., New Empire 

quadrangle, Lyon County, Nev. 

Facer Fol'llation 

1. Early Proterozoic 

2. Utah (NC) 

3. Crittenden, M. D., Jr., and Sorensen, M. L., 1980, The Facer 

Formation, a new early Proterozoic unit in northern Utah: 

U.S. Geol. Survey Bull. 1482-F, p. F1-F28 

4. Quartzite, pelitic schist, minor limestone and conglomerate 

5. White to pale-rusty-brown, bright-green 

6. 1 ,000 m 

1. Low-grade regional metamorphism; quartzite forms cliffs, 

ledges, supports highest peaks 

9. Base everywhere in thrust contact with Paleozoic rocks; 

unconformably underlies Huntsville sequence of Late Proterozoic and Early Cambrian age 

10. Type section: Exposures from N slope Willard Canyon, N1/2 

sec. 19, T. 8 N., R.1 W., to head of Facer Creek, SE1/4 

sec. 18, T. 18 N., R. 1 W., W face of Wasatch Mountains, 

S of Brigham City, Mantua quadrangle, Box Elder County, 

Utah. Named for Facer Creek. 

Factory Shoals Fol'lllation (Sandy Springs Group) 

1. Precambrian, late(?) and (or) Paleozoic, early(?) 

2. Georgia (NW) 

3. Higgins, M. w~, and McConnell, K. I., 1978, The Sandy 

Springs Group and related rocks in the Georgia Piedmont--

nomenclature and stratigraphy:. U.S. Geol. Survey Bull. 

1457-A, p. A103 (Also published in: Georgia Geol. Survey 

Bull. 93, p. 53, 1978) 

4. Garnet-biotite-oligoclase-muscovite-quartz schist locally 

containing kyanite or staurolite, with interlayered micaceous quartzite and metagraywacke 

5. Light-gray, lustrous 

6. Range 1,000-2,000 m 

9. Gradationally overlies Chattahoochee Palisades Quartzite; 

gradationally underlies Rottenwood Creek Quartzite 

10. Type area: Exposures along Sweetwater Creek at Factory 

Shoals, Ben Hill quadrangle, Fulton County, Ga. 

Fall Brook Formation 

1. Late Silurian or Early Devonian 

2. Maine (WC) 

3. Pankiwskyj, K. A., and others, 1976, Stratigraphic relationships on the southeast limb of the Merrimack synclinorium in central and west-central Maine: Geol. Soc. 

America Mem. 146, p. 270, 275 

57 

4. Calcareous metasandstone, minor metapelite and metasiltstone 

6. Range 600-1,000 m 

7. Massive 

9. Overlies Parkman Hill Formation (in type locality), or 

Thompson Mountain or Sangerville Formation; conformably and 

gradationally underlies Solon Formation 

10. Type locality: Fall Brook in village of Solon, N Anson 

quadrangle, Somerset County, Maine. 
58 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Falling 

1 • 

2. 

3. 

Creek Member (Doswell Formation) 

Late Triassic 

Virginia (EC) 

Weems, R. E., 1980, Geology of the Taylorsville basin, 

Hanover County, Virginia: Virginia Div. Mineral Resources 

Pub. 27, p. 25-26 

4. 

5. 

6. 

7. 

9. 

10. 

Sandstone with interbedded siltstone, shale, and coal 

Black, green, grayish-orange 

354 m 

Laminated, flaggy sandstone, bioturbated siltstone, fossiliferous 

Conformably overlies Stagg Creek Member; conformably underlies Newfound Member 

Type section: Along Stagg Creek, beginning at Hanover 

Country Club 0.3 km N of Virginia Highway 54 and continuing 

S to contact with Petersburg Granite, Taylorsville basin, 

Hanover Academy quadrangle, Hanover County, Va. Named for 

Falling Creek 3.4 km NW of junction of U.S. Highway 1 and 

Virginia Highway 54 in Ashland. 

Falls Run Granite Gneiss (Fredericksburg Complex) 

1. Middle Silurian to Early Devonian 

2. Virginia (EC) 

3. Pavlides, Louis, 1980, Revised nomenclature and stratigraphic relationships of the Fredericksburg Complex and 

Quantico Formation of the Virginia Piedmont: U.S. Geol. 

Survey Prof. Paper 1146, p. 12-15 

4. Granite gneiss 

5. Pale-pink to white 

7. Coarse-grained, foliated, allochthonous refolded fold in 

type area 

9. Intrudes Holly Corner Gneiss and (S of type area) Po River 

Metamorphic Suite (autochthonous) 

10. Type area: Downstream from intersection of Falls Run and 

Virginia Route 654, Salem Church quadrangle, Stafford 

County, Va. 

Falmouth Intrusive Suite 

1. Carboniferous 

2. Virginia (EC) 

3. Pavlides, Louis, 1980, Revised nomenclature and stratigraphic relationships of the Fredericksburg Complex and 

Quantico Formation of the Virginia Piedmont: U.S. Geol. 

Survey Prof. Paper 1146, p. 20-22 

4. Granitoid and pegmatoid rocks 

1. Foliated granitoid, nonfoliated pegmatoid; dikes, sills, 

small plutons 

9. Intrudes Po River and Ta River Metamorphic Suites, Holly 

Corner Gneiss, and Falls Run Granite Gneiss, (all in Fredericksburg Complex), and Quantico Formati9n 

10. Type area: Exposures along Rappahannock River upstream from 

town of Falmouth, Stafford County, Va. 

Feltville 

1. 

2. 

3. 

Formation (Newark Supergroup) 

Early Jurassic 

New Jersey (NE) 

Olsen, P. E., 1980, The latest Triassic and Early Jurassic 

formations of the Newark Basin (eastern North America, 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Newark Supergroup)--stratigraphy, structure, and correlation: New Jersey Acad. Sci. Bull., v. 25, no. 2, p. 34 

4. Interbedded siltstone and sandstone in fining-upwards 

sequences; laminated limestone containing fossil fishes 

5. Red, buff, gray, white 

6. 170 m avg, range >18-600 m 

9. Overlies Orange Mountain Basalt; underlies Preakness 

Basalt. Unit was formerly a subdivision of upper part of 

Brunswick Formation of Klimmel (1897) 

10. Type section: Exposure along Blue Brook, 1 km SW of dam at 

Lake Surprise, Watchung Reservation (Union County Park Commission), Union County, N.J. Named for old village of Feltville. 

Fernwood Member (Topanga Canyon Formation) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E16-E17 

4. Sandstone interbedded with mudstone 

6. >375 m 

7. Fluvial to brackish-water pebbly sandstone in thick lenticular ledge-forming beds, channeled and crossbedded 

9. Conformably overlies and tongues into Saddle Peak Member; 

conformably underlies and tongues into Cold Creek Member 

10. Type locality: Exposures in vicinity of Fernwood, sees. 18 

and 19, T. 1 S., R. 16 W., and sees. 13 and 24, T. 1 S., 

R. 17 W., Santa Monica Mountains, Topanga quadrangle, Los 

Angeles County, Calif. 

Ferron Mountain Member (Flagstaff Limestone) 

1. Paleocene, late 

2. Utah (C) 

3. Stanley, K. 0., and Collinson, J. W., 1979, Depositional 

history of Paleocene-lower Eocene Flagstaff Limestone and 

coeval rocks, central Utah: Am. Assoc. Petroleum Geologists 

Bull., v. 63, ·no. 3, p. 316 

4. Interbedded limestone, dolomicrite, mudstone, with sandstone 

lenses 

5. Blue-gray, gray, white 

6. 165 m 

7. Brecciated, fossiliferous (mollusks); represents lower of 

two major high stands of Lake Flagstaff 

8. Eight informal units, A through H 

9. Conformably overlies North Horn Formation; underlies Cove 

Mountain Member (Flagstaff Limestone) 

10. Type locality: Cliffs and slopes along S face of Ferron 

Mountain, sec. 32, T. 19 s., R. 5 E., Wasatch Plateau, Sanpete County, Utah. 

Finch Dolostone Member (Whitehall Formation) 

1. Late Cambrian 

2. New York (NE), Vermont 

3. Fisher, D. W., 1977, Correlation of the Hadrynian, Cambrian 

and Ordovician rocks in New York State: New York State Mus. 

Map and Chart Ser., no. 25, p. 49 

59 
60 

~. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Dolostone with interbedded chert 

Medium-gray 

12.2 m, range 12.2-22.8 m 

Thin- to thick-bedded, laminated, fetid odor, abundant 

quartz vugs 

Overlies basal orthoquartzite (Mosherville Sandstone?) 

member; underlies Warner Hill Limestone Member 

Type locality: Ward Farm, 6.~ km NNE of intersection of 

U.S. Highway 4 and New York Highway 22 in Whitehall, Thorn 

Hill quadrangle, Washington County, N.Y. Named for Finch 

Marsh, 3.7 km NNE of Whitehall. 

Fine Creek Mills Granite 

1. Paleozoic, late(?) 

2. Virginia (EC) 

3. Poland, F. B., Glover, Lynn, III, and Mose, D. G., 1979, The 

geology of the rocks along the James River between Sabot and 

Cedar Point, Virginia, in Glover, Lynn, III, and Tucker, 

R. D., eds., Virginia Piedmont geology along the James River 

from Richmond to the Blue Ridge--Field trip 1, of Guides to 

field trips 1-3: Blacksburg, Va., Geol. Soc. America, 

Southeastern Sec., p. 13 

~. Two-feldspar biotite granite 

1. Foliation, flow-banding 

9. Intrudes State Farm Gneiss in core of NNE-trending antiform 

10. Type area: Exposures at Fine Creek Mills, S of James River, 

Powhatan County, Va. 

Fisher Ridge Member (Mahantango Formation) 

1. Middle Devonian 

2. Pennsylvania (C) 

3. Faill, R. T., Hoskins, D. M., and Wells, R. B., 1978, Middle 

Devonian stratigraphy in central Pennsylvania--a revision: 

Pennsylvania Geol. Survey, 4th ser., Gen. Geology Rept. 70, 

p. 14, 23-28 

4. Shale, siltstone 

5. Olive-gray 

6. 139 m, range 39-300 m 

7. Cyclic deposits, uniformly fine grained; lower part of major 

upward-coarsening cycle 

9. Overlies Dalmatia Member (Mahantango Formation) or Marcellus 

Formation where Turkey Ridge and Dalmatia Members are 

absent; underlies Montebello Member (Mahantango Formation) 

10. Type section: First and second abandoned quarries, counting 

from S, and quarry access road, along E side of Penn Central 

Railroad, at W end of Fisher Ridge, 4 km S of Dalmatia, 

Northumberland County, Pa. 

Fish Lake Complex 

1. Jurassic 

2. Alaska (EC) 

3. Stout, J. H., 1976, Geology of the Eureka Creek area, eastcentral Alaska Range: Alaska Div. Geol. and Geophys. 

Surveys Geol. Rept. 46, p. 21-23 ~. Dunite, gabbro, minor diorite 

7. Intrusive bodies and related gabbro dikes, conforming to 

bedding trends; compositional layering suggests differentiated layered sill 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

9. Intrusive into, and between, Paxson Mountain Basalt and 

Tangle Lakes Formation (Amphitheater Group); unconformably 

underlies Tertiary rocks 

10. Type locality: Exposures of main dunite body in low hills 

around Fish Lake, Eureka Creek area, Mount Hayes A-4 and A-5 

quadrangles, EC Alaska Range, Alaska. 

Flint Hill Gneiss 

1. Middle Proterozoic 

2. Virginia (NC) 

3. Lukert, M. T., Nuckols, E. B., and Clarke, J. W., 1977, 

Flint Hill Gneiss--a definition: Southeastern Geology, v. 19, no. 1, p. 19-28 

4. Biotite gneiss of granitic composition with veins of blue 

quartz 

5. Dark and light layers 

7. Finely layered, strongly foliated 

9. Intruded by Robertson River Formation and basaltic greenstone dikes 

10. Type locality: Large quarry 0.8 km E of community of Flint 

Hill, Rappahannock County, Va. 

Fogelin Hill Formation 

1. Late Silurian and Early Devonian(?) (Ludlovian to 

Siegenian?) 

2. Maine (NE) 

3. Roy, D. C., and Mencher, Ely, 1976, Ordovician and Silurian 

stratigraphy of northeastern Aroostook County, Maine: Geol. 

Soc. America Mem. 148, p. 41, 50 

4. Slate interlayered with calcareous sandstone and siltstone 

5. Light green and red 

6. >760 m 9. Conformably overlies Jemtland Formation (Perham Group); top 

not observed (forms axial terrain of Stockholm Mountain 

syncline) 

10. Type area: Exposures in village of Stockholm and along N-S 

road between Stockholm and Jemtland, Aroostook County, 

Maine. Named for Fogelin Hill, SW of Jemtland. 

Fort Edward Dolostone Member (Great Meadows Formation) 

1. Early Ordovician 

2. New York (NE), Vermont 

3. Fisher, D. W., 1977, Correlation of the Hadrynian, Cambrian 

and Ordovician rocks in New York State: New York State Mus. 

Map and Chart Ser., no. 25, p. 56 

4. Quartzose and calcitic dolostone 

5. Mottled 

6. Range 18.2-45.5 m 

7. Medium- to thick-bedded, vermicular, fossiliferous 

9. Transitionally overlies Winchell Creek Siltstone Member; 

abruptly underlies Smith Basin Limestone Member 

10. Type locality: Bushlea Farm, N of New York Highway 149 and 

1.6 km E of Smiths Basin on Champlain Canal, Hartford quadrangle, Washington County, N.Y. Named for village of Fort 

Edward, 16 km SW of type locality. 

Fort Pond Member (Nashoba Formation) 

1. pre-Silurian 

61 
62 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Massachusetts (C) 

Bell, K. G., and Alvord, D. C., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 184-185, 208, app. 1 (in pocket) 

Calc-silicate rocks with discontinuous beds of marble; 

amphibole-biotite gneiss; amphibolite 

1,470 m 

Fine- to medium-grained, stratified, relict sedimentary 

structures 

Overlies Nagog Pond Gneiss Member; underlies Long Pond 

Gneiss Member 

Type locality: Area near SE, NW, and SW shores of Fort Pond 

in town of Littleton, Westford quadrangle, Middlesex County, 

Mass. 

Foss Group 

1. Late Permian 

2. Oklahoma (C) 

3. Fay, R. 0., 1978, Geology and mineral resources (exclusive 

of petroleum) of Custer County, Oklahoma: Oklahoma Geol. 

Survey Bull. 114, p. 19-35 

4. Shale, siltstone 

5. Orange-brown, red-brown 

6. 110 m 

8. Cloud Chief Formation with its Moccasin Creek Bed, Kiger 

Member, Day Creek Bed, and Big Basin Member; Doxey Shale 

9. Overlies Rush Springs Formation (Whitehorse Group); underlies Elk City Sandstone 

10. Type locality: S side of Foss Reservoir between Clinton and 

Hammon, Custer County, Okla. Named for town of Foss, 

Washita County. 

Fossil Hill Member (Prida Formation)/Member (Favret Formation)/ 

Formation (Star Peak Group) 

1. Middle Triassic (Anisian and Ladinian) 

2. Nevada (NW) 

3. Nichols, K. M., and Silberling, N. J., 1977, Stratigraphy 

and depositional history of the Star Peak Group (Triassic), 

northwestern Nevada: Geol. Soc. America Spec. Paper 178, 

p. 20-23, 39-41, 45-48 

4. Interstratified limestone, calcareous mudstone, siltstone, 

and shale 

5. Dark-gray, yellowish-brown, pinkish-gray 

6. 60 m, range <1-200 m 7. Fossiliferous, flaggy, laterally discontinuous beds, platform carbonate deposit 

9. Disconformably overlies unnamed lower member and gradationally underlies unnamed upper member of Prida Formation (Star 

Peak Group) 

10. Type section: S side of Fossil Hill, NW1/4SE1/4 sec. 19, 

T. 28 N., R. 35 E., SE Humboldt Range, Pershing County, Nev. 

Frame Member (Wristen Formation) 

1. Late Silurian 

2. Texas (WC) 

3. Hills, J. M., and Hoenig, M. A., 1979, Proposed type sec- tions for Upper Silurian and Lower Devonian subsurface units 

in Permian Basin, west Texas: Am. Assoc. Petroleum 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Geologists Bull., v. 63, no. 9, p. 1510-1511 

4. Calcareous shale, shaly limestone 

5. Green-gray, blue-gray 

6. 61 m, range <1-61 m 

9. Conformably overlies Wink Member (Wristen Formation); uncon- formably underlies Thirtyone Formation10. Type section: Wilshire Oil Co. 1 Atlantic Frame well, 

depth-interval 2036-2097 m, Sec. 8, Blk. 10, H & GN Survey, 

Pecos County, Tex. 

Franklinville Gneiss • 

1. Cambrian-Ordovician(?) 

2. Maryland (NC) 

3. Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the eastern Maryland Piedmont: Maryland Geol. Survey Rept. Inv. 27, 

p. 16 

4. Biotite-quartz-plagioclase gneiss 

7. Medium- to coarse-grained 

9. Overlies Bradshaw Layered Amphibolite (Baltimore Mafic 

Complex) in NE-SW syncline 

10. Type locality: Outcrops on either side of bridge that crosses Little Gunpowder Falls at Franklinville, White Marsh 

quadrangle, Baltimore County, Md. 

Furner Valley Lilllestone (Oquirrh Group) 

1. Late Pennsylvanian and Early Permian (Missourian to Wolfcampian) 

2. Utah (C) 

3. Morris, H. T., Douglass, R.· C. , and Kopf, R. W., 1977, 

Stratigraphy and microfaunas of the Oquirrh Group in the 

southern East Tintic Mountains, Utah: U.S. Geol. Survey 

Prof. Paper 1025, p. 6-8 

4. Limestone with chert masses, hydrothermal dolomite 

5. Gray, blue-gray 

6. 1,595 m, range 1,524-1,829 m 

7. Thin- to medium-bedded, ledge-forming, fossiliferous 

(fusulinids) 

9. Conformably overlies Bingham Mine Formation (Oquirrh Group); 

disconformably underlies Diamond Creek Sandstone 

10. Type section: E side of Jericho Ridge, E1/2 sees. 6, 7, and 

18, T. 13 S., R. 2 W., S East Tintic Mountains, Furner Ridge 

quadrangle, Juab County, Utah. Named for Furner Valley, 

which separates Jericho and Furner Ridges. 

Gallagher Peak Sandstone Member (Snaky Canyon Formation) 

1. Late Pennsylvanian (Missourian) 

2. Idaho (SE) 

3. Skipp, Betty, and others, 1979, Upper Paleozoic carbonate 

bank in east-central Idaho--Snaky Canyon, Bluebird Mountain, 

and Arco Hills Formations, and their paleotectonic significance: U.S. Geol. Survey Bull. 1486, p. 28-29 

4. Calcareous, quartzose sandstone 

5. Medium-gray and light-brownish-gray 

6. 59 m 7. Very fine grained, thin-bedded 

9. Gradationally overlies Bloom Member; gradationally underlies 

Juniper Gulch Member 

63 
64 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Type section: Exposures on summit of Gallagher Peak, 

sec. 21, T. 9 N., R. 32 E., Copper Mountain quadrangle, 

Clark County, Idaho. 

Gene Canyon Formation 

1. Oligocene(?), late, to Miocene, early 

2. California (SE), Arizona 

3. Davis, G. A., and others, 1980, Mylonitization and detachment faulting in the Whipple-Buckskin-Rawhide Mountains 

terrane, southeastern California and western Arizona: Geol. 

Soc. America Mem. 153, p. 93-95 

4. Sandstone, interbedded with andesitic(?) volcanic rocks, 

debris flows of crystalline rocks, siltstone, and limestone 

5. Red, buff 

6. 585 m 

1. Unit in allochthonous upper-plate assemblage separated from 

lower-plate assemblage by subhorizontal detachment fault 

9. Overlies upper-plate crystalline basement rocks; unconformably underlies Copper Basin Formation or Osborne Wash Formation 

10. Type area: Gene Canyon, E Whipple Mountains, Gene Wash 

quadrangle, San Bernardino County, Calif. 

Georges 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10 0 

Creek Member (Paluxy Sand) 

Early Cretaceous 

Texas (C) 

Owen, M. T., 1979, The Paluxy Sand in north-central Texas: 

Baylor Geol. Studies Bull. 36, p. 8, 21-25 

Sand, silt, clay, sandstone, limestone 

Red, white 

10 m, range 2-31 m 

Cross-bedded, fluvial and subtidal deposits 

Disconformably overlies Lake Merritt Member; unconformably 

underlies Eagle Mountain Member 

Type locality: Georges Creek along county road at Capitol 

Silica Quarry, 12.8 km E of Glen Rose, Somervell County, 

Tex. 

Gettel Member (Laketown Dolostone) 

1. Middle Silurian 

2. Utah (WC), Nevada 

3. Budge, D. R., and Sheehan, P.M., 1980, The Upper Ordovician 

through Middle Silurian of the eastern Great Basin--Pt. 1, 

Introduction--historical perspective and stratigraphic synthesis; Pt. 2, Lithologic descriptions: Milwaukee Public 

Mus. Contr. Biology and Geology, no. 28, p. 19-20 (pt. 1); 

no. 29, p. 17 (pt. 2) 

4. Argillaceous dolomite 

5. Olive-gray, weathers brownish gray 

6. 11.6 m 1. Finely crystalline, medium- to thick-bedded, fossiliferous 

9. Overlies High Lake Member; underlies Portage Canyon Member 

or, as at type section, Jack Valley Member 

10. Type section: W of Gettel Playa, NE1/4SW1/4 sec. 26, 

T. 21 S., R. 14 W., Barn Hills, Confusion Range, Millard 

County, Utah. Unit is restricted to S part of study area. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Ghost Dance Lava Member (Hu-pwi Rhyodacite) 

1. Miocene 

2. Nevada (WC) 

3. Ekren, E. B., and others, 1980, Stratigraphy, preliminary 

petrology, and some structural features of Tertiary volcanic 

rocks in the Gabbs Valley and Gillis Ranges, Mineral County, 

Nevada: U.S. Geol. Survey Bull. 1464, p. 38-39 

4. Rhyodacitic flow breccia and lava 

5. Brownish-gray, black 

6. Range <1-100 m 

7. Porphyritic, flow-banded lava with layers alternately rich 

and poor in phenocrysts 

9. Overlies Nugent Tuff Member; underlies Poinsettia Tuff 

Member; contacts are low-angle detachment faults 

10. Type locality: Hidden Wash, 3.2 km E of Ghost Dance Ridge, 

T. 11 N., R. 30 E., Gillis Range, Mineral County, Nev. 

Gibraltar Lake Tuff 

1. Oligocene(?) to Pliocene(?) 

2. Alaska (C) 

3. Detterman, R. L., and Reed, B. L., 1980, Stratigraphy, 

structure, and economic geology of the Iliamna quadrangle, 

Alaska: U.S. Geol. Survey Bull. 1368-B, p. B56-B58 

4. Rhyolitic crystal and lithic tuff 

5. Lower member: light-gray to tan; upper member: light-gray 

to white 

6. Lower member: range 300-730 m; upper member: range 30-

182 m 

8. Informal lower welded tuff member and upper ash-flow tuff 

member 

9. Unconformably overlies older Tertiary volcanic rocks; 

locally unconformably underlies Intricate Basalt 

10. Type locality: Exposures on mountain W of Emerald Lake, S 

of Iliamna Lake, Iliamna quadrangle, Alaska Peninsula, 

Alaska. Named for nearby Gibraltar Lake. 

Gilmer Limestone (Louark Group) 

1. Late Jurassic 

2. Texas (EC) 

3. Forgotson, J. M., and Forgotson, J. M., Jr., 1976, Definition of Gilmer Limestone, Upper Jurassic formation, northeastern Texas: Am. Assoc. Petroleum Geologists Bull., v. 

60, no. 7, p. 1119-1123 

4. Micritic limestone, oolitic limestone, shale 

5. Gray, brown 

6. 97 m 1. Subsurface, depositional basin 

9. Overlies Smackover Formation or Buckner Formation (Louark 

Group); unconformably underlies Bossier Formation (Cotton 

Valley Group) 

10. Type section: Arkansas Louisiana Gas Co. Indian Rock Gas 

Unit 2 well, depth-interval 3542-3639 m, Maria Finolia 

Flores Survey A-2, Gilmer field, 5 km E of Gilmer, Upshur 

County, Tex. 

Glen Creek Gabbro (Roosevelt Gabbros) 

1. Cambrian 

2. Oklahoma (C) 

65 
66 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Powell, B. N., Gilbert, M. c., and ·Fischer, J. F., 1980, 

Lithostratigraphic classification of basement rocks of the 

Wichita province, Oklahoma--summary: Geol. Soc. America 

Bull., pt. 1, v. 91, no. 9, p. 510-513 

Biotite-amphibole-olivine gabbro with ultramafic segregations and concentrations of magnetite and ilmenite 

Weathers olive brown 

>30 m 

Ophitic, poikilitic, medium-grained, sill-like intrusive 

body 

Intrudes Glen Mountains Layered Complex (Raggedy Mountain 

Gabbro Group) 

Type locality: Outcrops W of Glen Creek, NE1/4SW1/4 sec. 14, T. 4 N., R. 17 W., Glen Mountains, Kiowa County, 

Okla. 

Glen Mountains Layered Complex (Raggedy Mountain Gabbro Group) 

1. Precambrian to Cambrian 

2. Oklahoma (C) 

3. Powell, B. N., Gilbert, M. c., and Fischer, J. F., 1980, 

Lithostratigraphic classification of basement rocks of the 

Wichita province, Oklahoma--summary: Geol. Soc. America 

Bull., pt. 1, v. 91, no. 9, p. 509-510 

4. Feldspathic cumulates including anorthosite, anorthositic 

gabbro, and troctolite 

5. Tan, light-gray 

6. >240 m 

7. Medium- to coarse-grained, igneous lamination and gravitational layering 

B. Informal G, K, L, and M zones 

9. Base not exposed; intruded by Roosevelt Gabbros; underlies 

sills of younger granites emplaced along erosional unconformity between complex and overlying Carlton Rhyolite Group 

10. Type area: Glen Mountains, T. 4 N., Rs. 16 and 17 W., Kiowa 

County, Okla. 

Glen Township Formation (Mille Lacs Group) 

1. Precambrian, middle 

2. Minnesota (C) 

3. Morey, G. B., 1978, Lower and middle Precambrian stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol, Survey Rept. Inv. 21, p. 20-21 

4. Interbedded sulfide-rich carbonaceous slate, cherty ironformation, metabasalt, and epiclastic sedimentary rocks 

6. 3,000 m 

7. Highly metamorphosed 

9. Overlies and grades laterally into Denham Formation (Mille 

Lacs Group); underlies argillaceous rocks of Mille Lacs 

Group, undivided 

10. Type locality: Drilling logs and core samples from 55 holes 

in sec. 28, T. 46 N., R. 25 W., Glen Township, Aitkin 

County, Minn. 

Goat Mountain Schists 

1. Middle Jurassic(?) 

2. California (NW) 

3. Suppe, John, and Foland, K. A., 1978, The Goat Mountain 

Schists and Pacific Ridge Complex: A redeformed but still-
LEXICON OF GEOLOGIC NAMES OF THE UNITgD STATES 

intact late Mesozoic Franciscan schuppen complex, in Howell 

and McDougall, eds., Mesozoic paleogeography of the-western 

United States: Soc. Econ. Paleontologists and Mineralogists, Pacific Sec., Pacific Coast Paleogeography Symposium 

2, p. 431-451 

4. Coarsely crystalline hornblende schist, metabasalt, metachert, actinolite-chlorite schist, and serpentinite 

1. Coarse-grained 

9. Structurally interlayered with Pacific Ridge Complex in 

Franciscan terrane 

10. Type area: 800 m along ridge extending W from Goat Mountain 

summit, lat 39°30' N., long 122°45' W., Stonyford quadrangle, Lake County, Calif. 

Gold Ace Limestone Member (Carrara Formation) 

1. Early Cambrian 

2. Nevada (SC), California 

3. Palmer, A. R., and Halley, R. B., 1979, Physical stratigraphy and trilobite biostratigraphy of the Carrara Formation 

(Lower and Middle Cambrian), southern Great Basin: U.S. 

Geol. Survey Prof. Paper 1047, p. 13-14 

4. Microspar limestone deposited as lime mudstone 

5. Dark-gray 

6. 46 m, range <1-103 m 

1. Thin- to medium-bedded, cliff-forming, burrowed, oncolitic, 

fossil fragments 

9. Gradationally overlies Echo Shale Member; underlies with 

sharp contact Pyramid Shale Member 

10. Type section: Exposure in canyon 0.8 km NW of Carrara 

Canyon, near Gold Ace Mine, Bare Mountain quadrangle, Nye 

County, Nev. 

Goose Creek Conglomerate Member (Bull Run Formation) 

1. Late Triassic 

2. Virginia (NE) 

3. Lindholm, R. C., 1979, Geologic history and stratigraphy of 

the Triassic-Jurassic Culpeper Basin, Virginia: Geol. Soc. 

America Bull. (pts. 1 and 2), v. 90, no. 11, p. 996 (pt. 1, 

summary); p. 1721-1722 (pt. 2, microfiche) 

4. Silicate pebble conglomerate 

5. Greenish and grayish pebbles 

6. >900 m 1. Member separated on basis of clast lithology; clasts derived 

from metamorphic rocks of the Blue Ridge province 

9. Conglomeratic masses within main body of Bull Run Formation 

in its upper part; underlies Buckland Formation on W side of 

Culpeper basin 

10. Type locality: Exposures on S side of Goose Creek, 2 km E 

of confluence of Goose Creek and Little River, Culpeper 

basin, Loudoun County, Va. 

Gordon Pass Formation (Big Cypress Group) 

1. Early Cretaceous (Comanchean) 

2. Florida (SE) 

3. Winston, G. D., 1976, Six proposed formations in the undefined portion of the Lower Cretaceous section in south 

Florida: Gulf Coast Assoc. Geol. Socs. Trans., v. 26, p. 71 

4. Anhydrite interbedded with micritic limestone and dolomite 

67 
68 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

159 m 

Dense limestone at base, thin anhydrite bed at top 

Overlies Marco Junction Formation; underlies Dollar Bay 

Formation 

Type section: Humble No. 1 Collier Corp. well, depthinterval 3,109-3,268 m, sec. 27, T. 50S., R. 26 E., Collier 

County, Fla. Named for Gordon Pass, which connects Gulf of 

Mexico with barrier-beach lagoon 9.6 km W of type well. 

Grande Ronde Basalt (Yakima Basalt Subgroup of Columbia River Basalt 

Group) 

1. Miocene, early and middle 

2. Washington (SE), Idaho, Oregon 

3. Swanson, D. A., and others, 1979, Revisions in stratigraphic 

nomenclature of the Columbia River Basalt Group: U.S. Geol. 

Survey Bull. 1~57-G, p. G16-G2~ 

~. Tholeiitic basalt 

6. Range ~50-1,000 m 

7. Fine-grained, aphyric, cliff-forming, numerous flows range 

<1->100 m thick 

8. Four informal magnetostratigraphic units 

9. Conformably overlies Imnaha Basalt or overlies and intertongues with Picture Gorge Basalt; conformably and disconformably underlies Wanapum Basalt or disconformably underlies Saddle Mountains Basalt (both in Yakima Basalt 

Subgroup) 

10. Type locality: Exposures on W-trending spur ridge extending 

from NW1/~ sec. 23 across N1/3 sec. 22 to NE1/~ sec. 21, 

T. 7 N., R. ~6 E., lower Grande Ronde River Valley, Black 

Butte quadrangle, Asotin County, Wash. 

Granger Mountain Member (Oquirrh Formation) 

1. Early Permian (Wolfcampian) 

2. Utah (C) 

3. Baker, A. A., 1976, Geologic map of the west half of the 

Strawberry Valley quadrangle, Utah: U.S. Geol. Survey Misc. 

Inv. Ser. Map I-931, p. 2-3 

~. Limy and silty sandstone interbedded with quartzite and 

limestone 

5. Gray, weathers tan 

6. 1,500 m; range 1,500-2,200 m 7. Wormlike trail markings, fusulinids 

9. Overlies Wallsburg Ridge Member (Oquirrh Formation); underlies Kirkman Limestone 

10. Type locality: On SE flank of Granger Mountain, extending 

along walls of Right Fork of Hobble Creek from mouth of Days 

Canyon to mouth of Cedar Canyon, NW1/~ sec. 3~ to SW1/4 sec. 24, T. 7 s., R. ~ E., Utah County, Utah. 

Greenleaf Lake Li•estone Member (McCully Formation) 

1. Middle Pennsylvanian (Morrowan) 

2. Oklahoma (EC) 

3. Sutherland, P. K., and Henry, T. w., 1977, Carbonate platform facies and new stratigraphic nomenclature of the 

Morrowan Series (Lower and Middle Pennsylvanian), northeastern Oklahoma: Geol. Soc. America Bull., v. 88, no. 3, 

p. 434 

4. Limestone 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

6. 6.4 m, range 4.7-9.1 m 

1. Micritic and skeletal calcarenite (wackestone, packstone), 

fossiliferous 

9. Conformably overlies informal shale "A" member (McCully 

Formation); underlies informal shale "B" member (McCully 

Formation), or unconformably underlies Atoka Formation 

10. Type section: Measured Section 42, on bluff immediately E 

of Greenleaf Lake Dam, sec. 36, T. 14 N., R. 20 E., Muskogee 

County, Okla. 

Greenleaf Mountain Fo~ation 

1. pre-Silurian (late Precambrian? to Ordovician?) 

2. Massachusetts (C) 

3. Bell, K. G., and Alvord, D. c., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 188-189, 202-203, app. 1 (in pocket) 

4. Oligoclase-hornblende amphibolite 

5. Dark-greenish-gray to dark-gray 

·6. 225 m 

1. Fine-grained, thin-bedded, relict sedimentary structures 

9. Unconformably overlies unnamed quartzites and gneisses and 

Middlesex Fells Volcanic Complex; underlies Burlington 

Formation 

10. Type locality: Greenleaf Mountain, N Lexington quadrangle, 

Middlesex County, Mass. 

Green Mountain Formation, 

1. Early Proterozoic 

2. Wyoming (SC) 

3. Divis, A. F., 1976, Geology and geochemistry of Sierra Madre 

Range, Wyoming: Colorado School Mines Quart., v. 71, no. 3, 

p. 18-21 

4. Metamorphosed calc-alkaline volcanic-sedimentary rocks 

including sericitic quartzite, marble, conglomerate, felsic 

and mafic schists 

9. Overlies Archean quartz-biotite gneiss; overlies and intergrades with Big Creek Gneiss; intruded by Encampment River 

Granodiorite; underlies Libby Creek Group with structural 

unconformity 

10. Type area: Exposures near Green Mountain, lat 41°07'30" N., 

long 106°55' W., Sierra Madre Range, Carbon County, Wyo. 

Griffins Landing Sand Member (Dry Branch Formation) 

1. Eocene, late 

2. Georgia (EC) 

3. Huddlestun, P. F., and Hetrick, J. H., 1979, The stratigraphy of the Barnwell Group of Georgia: Georgia Geol. 

Survey Open File Rept. 80-1, p. 24-25, 54-58 

4. Calcareous sand with limestone and shell beds and clay 

lenses 

6. 19.1 m 

1. Massive to rudely bedded, fossiliferous 

9. Overlies Clinchfield Formation; interfingers with Twiggs 

Clay Member and Irwinton Sand Member (Dry Branch Formation); 

underlies Tobacco Road Sand; all units in Barnwell Group 

10. Type locality: Exposure at Griffins Landing on Savannah 

River, 2.25 km N of junction of Griffins Landing Road and 

River Road, 8.4 km N of Girard, Burke County, Ga. 

69 
70 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Guild Mine Member (Mickey Pass Tuff) 

1. Oligocene 

2. Nevada (WC) 

3. Proffett, J. M., Jr., and Proffett, B. H., 1976, Stratigraphy of the Tertiary ash-flow tuffs in the Yerington 

district, Nevada: Nevada Bur. Mines and Geology Rept. 27, 

p. 10-16 

4. Dacite, quartz latite, and rhyolite ash-flow tuff 

5. Brown, pink, lavender 

6. 790 m, range 520-790 m 

7. Strongly welded, crystal-rich cooling unit 

8. Unnamed map units 1, 2, 3 

9. Unconformably overlies unnamed early Tertiary rocks; underlies Weed Heights Member (map unit 6) or intervening unnamed 

map units 5 or 4 of Mickey Pass Tuff 

10. Type area: Exposures 2 km SW of Guild Placer mines, 

Singatse Range, Lyon County, Nev. 

Gushee Member (Penobscot Formation) 

1. Ordovician 

2. Maine (SE) 

3. Bickel, C. E., 1976, Stratigraphy of the Belfast quadrangle, 

Maine: Geol. Soc. America Mem. 148, p. 116 

4. Sulfidic anthophyllite-cordierite rock, amphibolite, quartzalbite granofels, minor mica schist 

5. Weathers rusty or chalky 

6. 500 m 

7. Coarse- to fine-grained; relict scoria and pillows in 

amphibolite 

9. Belt of rocks in Penobscot Formation near its contact with 

Appleton Ridge Formation along St. George fault 

10. Type area: Roland Gushee Farm, Appleton Township, Belfast 

quadrangle, Waldo County, Maine. 

Haldane Bentonite Bed (Loves Park Member of Dunleith Formation)/ 

(Wall Member of Dunleith Formation) 

1. Middle Ordovician 

2. Illinois (NC) 

3. Willman, H. B., and Kolata, D. R., 1978, The Platteville and 

Galena Groups in northern Illinois: Illinois Geol. Survey 

Circ. 502, p. 50 

4. Bentonite clay 

6. 0.05 m 

7. Bed marked by strong reentrant in exposures 

9. In type section, overlies and underlies dolomite units in 

upper part of Loves Park Member; toW, in Galena, Ill., 

area, is in middle part of Wall Member 

10. Type section: Victory School Section, abandoned quarry on W 

side of Pine Creek, N of Victory School, 3.2 km SW of 

Mt. Morris, NW1/4SW1/4SE1/4 sec. 32, T. 24 N., R. 9 E., Ogle 

County, Ill. Named for town of Haldane, 8 km NW of type 

section. 

Hamburg Member (Leithsville Formation) 

1. Early Cambrian 

2. New Jersey (NC) 

3. Markewicz, F. J., and Dalton, Richard, 1977, Stratigraphy 

and applied geology of the lower Paleozoic carbonates in 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

northwestern New Jersey--Field Conference of Pennsylvania 

Geologists, 42d, Stroudsburg, 1977, Guidebook: [Harrisburg, 

Pennsylvania Geol. Survey] p. 13-14 

4. Dolomite, shale, siltstone, sandstone 

6. 29 m 7. Rhythmically bedded cycles representative of mudflat to 

lagoonal environments 

9. Overlies Califon Member; underlies Wallkill Member 

10. Type section: Steep hillside, 0.4 km S of New Jersey Route 

94, 0.8 km W of Hamburg, Sussex County, N.J. 

Happy Valley Branch Member (James Run Formation) 

1. Paleozoic, early 

2. Maryland (NE) 

3. Higgins, M. W., 1977, Six new members of the James Run 

Formation, Cecil County, northeastern Maryland: U.S. Geol. 

Survey Bull. 1435-A, p. A127 

4. Metamorphosed felsic volcaniclastic rocks with relict phenocrysts of sodic plagioclase and quartz 

5. Light-gray to white 

6. 915 m 

7. Fine-grained, medium- to thin-bedded 

9. Overlies Gilpins Falls Member; probably partly equivalent to 

Big Elk Creek and Principio Creek Members 

10. Type section: Exposed from just N of Happy Valley Branch, 

tributary of Susquehanna River, to contact with Gilpins 

Falls Member about 1,220 m NW of U.S. Highway I-95, Cecil 

County, Md. 

Harleyville Member (Cooper Formation) 

1. Eocene, late(?) and Oligocene(?), early 

2. South Carolina (C) 

3. Ward, L. W., and others, 1979, Stratigraphic rev1s1on of 

Eocene, Oligocene, and lower Miocene formations of South 

Carolina: South Carolina Geol. Survey Geol. Notes, v. 23, no. 1, p. 18-23 

4. Phosphatic, clayey calcarenite 

5. Olive-gray, greenish-gray 

6. 3 m, range 3-30 m 

1. Compact, fine-grained, fossiliferous 

9. Unconformably overlies Cross Member (Santee Limestone); 

unconformably underlies Parkers Ferry Member or Ashley 

Member (Cooper Formation) 

10. Type section: Section at Giant Portland Cement Co. quarry, 

3.2 km N of Harleyville, just E of Route 453, Ridgeville 15' 

quadrangle, Dorchester County, S.C. Named for nearby town 

of Harleyville. 

Harmonyvale Member (Ontelaunee Formation) 

1. Early Ordovician 

2. New Jersey (NC) 

3. Markewicz, F. J., and Dalton, Richard, 1977, Stratigraphy 

and applied geology of the lower Paleozoic carbonates in 

northwestern New Jersey--Field Conference of Pennsylvania 

Geologists, 42d, Stroudsburg, 1977, Guidebook: [Harrisburg, 

Pennsylvania Geol. Survey] p. 22-23 

4. Dolomite, chert, limestone 

5. Light-gray 

71 
72 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

>67 m Fine-grained to cryptocrystalline, stylolitic, fossiliferous 

Overlies Beaver Run Member (Ontelaunee Formation); unconformably underlies Jacksonburg Formation 

Type section: Not stated, although unit is described in 

measured sections. Probably named for Harmonyvale, a 

village about 5 km WSW of Hamburg, Sussex County, N.J. 

Harris wash Tongue (Page Sandstone) 

1. Middle Jurassic (Bajocian) 

2. Utah (SC) 

3. Peterson, Fred, and Pipiringos, G. N., 1979, Stratigraphic 

relations of the Navajo Sandstone to Middle Jurassic formations in parts of southern Utah and northern Arizona: U.S. 

Geol. Survey Prof. Paper 1035-B, p. B27-B29 

4. Sandstone 

5. Gray to reddish-brown or grayish-red 

6. 18.3 m, range <1-36.6 m 

1. Fine-grained, crossbedded, forms smooth cliff 

9. Unconformably overlies Navajo Sandstone (Glen Canyon Group); 

underlies Judd Hollow Tongue (Carmel Formation of San Rafael 

Group), which separates it from Thousand Pockets Tongue 

(Page Sandstone) 

10. Type section: W side Halfway Hollow, 0.8 km from junction 

with Harris Wash, 20 km SE of Escalante, NE1/4SE1/4NE1/4 

sec. 26, T. 36 S., R. 4 E., Garfield County, Utah. 

Hart Ledge Complex (White Mountain Plutonic-Volcanic Series) 

1. Jurassic and Cretaceous(?) 

2. New Hampshire (C) 

3. Henderson, D. M., and others, 1977, Geology of the Crawford 

Notch quadrangle, New Hampshire: Concord, New Hampshire 

Dept. Resources and Econ. Devel., p. 11 

4. Syenite, quartz syenite, ferrorichterite granite, and 

riebeckite granite 

5. Green, buff, white 

1. Medium- to coarse-grained; circular and arcuate bodies of 

map-units form circular pluton 5 km across 8. Four informal lithologic map-units 

9. Apparently intrudes, and may be younger than, Mount Osceola 

Granite (White Mountain Plutonic-Volcanic Series) 

10. Type area: From Hart Ledge SW to Mount Tremont, Crawford 

Notch quadrangle, Grafton and Carroll Counties, N.H. 

Harwood 

1 • 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Member (Poplar River Formation) 

Pleistocene (Wisconsinan) 

North Dakota (EC) 

Arndt, B. M., 1977, Stratigraphy of offshore sediment, Lake 

Agassiz--North Dakota: North Dakota Geol. Survey Rept. 

Inv. 60, p. 8 

Clay 

Gray, gray-brown 

1.8 m 

Mealy texture; fluvial-overbank deposits 

Unconformably overlies Brenna Formation; conformably underlies West Fargo Member (Poplar River Formation) or uncon- formably underlies Sherack Formation 

Type section: Boring T-18, North Dakota Geol. Survey test-
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

hole, SW1/4SW1/4SW1/4 sec. 11, T. 147 N., R. 49 W., Traill 

County, N. Dak. Named for village of Harwood, Cass County. 

Hayfork Bally Meta-andesite 

1. Jurassic(?) 

2. California (NW) 

3. Irwin, W. P., 1977, Review of Paleozoic rocks of the Klamath 

Mountains: in Stewart, J. H., and others, eds., Paleozoic 

paleogeography of the western United States--Pacific Coast 

Paleogeography Symposium 1 [Bakersfield, Calif., 1977]: Los 

Angeles, Soc. Econ. Paleontologists and Mineralogists, 

Pacific Sec., p. 448 

4. Meta-andesite 

5. Light- to dark-gray-green 

6. >1 ,000 m 

7. Fine-grained groundmass, bedded, forms blocky outcrops and 

light-colored soil; lowest unit of Hayfork terrane 

9. Intruded by Jurassic Ironside Mountain batholith and 

Wildwood pluton; structurally underlies middle unit of 

Hayfork terrane, or unconformably underlies Cretaceous or Tertiary rocks 

10. Type locality: Exposures along main Forest Service road 

that crosses N slope of Hayfork Bally at altitude of 1,200-

1,370 m, sees. 27 and 28, T. 33 N., R. 12 E., and along 

branch of that road that climbs N and W slopes of peak to 

lookout tower, Hayfork quadrangle, Trinity County, Calif. 

Haywood Landing Member (Belgrade Formation) 

1. Miocene, early 

2. North Carolina (EC) 

3. Ward, L. W., Lawrence, D. R., and Blackwelder, B. W., 1978, 

Stratigraphic revision of the middle Eocene, Oligocene, and 

lower Miocene--Atlantic Coastal Plain of North Carolina: 

U.S. Geol. Survey Bull. 1457-F, p. F15-F16 

4. Phosphatic, calcareous, clayey, shelly quartz sand 

5. Gray to brown 

6. 3 m, range 3-31 m 

7. Unconsolidated; offshore equivalent of nearshore Pollocksville Member 

9. Unconformably overlies River Bend Formation; unconformably 

underlies Duplin Formation 

10. Type locality: Outcrop at Haywood Landing, L bank of White 

Oak River, 1.2 km below mouth of Holston Creek, Jones 

County, N.C. 

Hickory Hills Till Member (Wolf Creek Formation) 

1. Pleistocene (pre-Wisconsinan) 

2. Iowa (C) 

3. Hallberg, G. R., 1980, Pleistocene stratigraphy in eastcentral Iowa: Iowa Geol. Survey Tech. Inf. Ser., no. 10, 

p. 14-37 

4. Sandy till, pebble loam 

5. Yellowish-brown to dark-gray 

6. 16.5 m 

7. Loam-textured till 

9. Unconformably overlies informal Dysart paleosol or Aurora 

Till Member; as the upper unit of Wolf Creek Formation, 

unconformably underlies late Sangamon pedisediment 

73 
74 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Type section: 402 roadcut and core section, Hickory Hills 

Park, on W end of Caseys Paha, where State Highway 21 cuts 

through paha, NW1/4SE1/4 sec. 10, T. 86 N., R. 13 W., Tama 

County, Iowa. 

High Lake Member (Laketown Dolostone) 

1. Early Silurian 

2. Utah (NC), Nevada 

3. Budge, D. R., and Sheehan, P.M., 1980, The Upper Ordovician 

through Middle Silurian of the eastern Great Basin--Pt. 1, 

Introduction--historical perspective and stratigraphic 

synthesis; Pt. 2, Lithologic descriptions: Milwaukee Public 

Mus. Contr. Biology and Geology, no. 28, p. 19 (pt. 1); 

no. 29, p. 6 (pt. 2) 

4. Dolomite with chert seams and nodules 

5. Gray 

6. 105 m 7. Finely to coarsely crystalline, medium- to thick-bedded, 

lenticular., laminated 

9. Overlies Tony Grove Lake Member; underlies Portage Canyon 

Member, as at type section, or Gettel Member 

10. Type section: SW1/4SW1/4 sec. 5, T. 13 N., R. 3 E., Tony 

Grove Lake, Bear River Range, Cache County, Utah. Derivation of name not stated. 

Hoko River Formation (Twin River Group) 

1. Eocene, late (Narizian) 

2. Washington (NW) 

3. Snavely, P. D., Jr., Niem, A. R., and Pearl, J. E., 1978, 

Twin River Group (upper Eocene to lower Miocene)--defined to 

include the Hoko River, Makah, and Pysht Formations, Clallam 

County, Washington: U.S. Geol. Survey Bull. 1457-A, 

p. A 111-A 11 5 

4. Siltstone, with interbeds of phyllitic and basaltic sandstone, pebbly sandstone, and conglomerate 

6. 1,600 m, range 1,600-2,300 m 

7. Thin-bedded to massive siltstone; conglomerate and sandstone 

channels; calcareous concretions; fossiliferous 

9. Conformably overlies, or intertongues with, Lyre Formation; 

gradationally, or locally unconformably, underlies Makah 

Formation (Twin River Group) 

10. Type locality: Exposures in stream bed and cliffs of Hoko 

River and in railway and road cuts parallel to river from 

point 1 km N of junction of Blue Canyon with Hoko River S to 

point 1.5 km N of Hoko Falls bridge, NW Olympic Peninsula, 

Clallam County, Wash. 

Hollofield Layered Ultramafite (Baltimore Mafic Complex) 

1. Cambrian(?) 

2. Maryland (NC) 

3. Crowley, w. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the east- ern Maryland Piedmont: Maryland Geol. Survey Rept. Inv. 27, 

p. 13-14, 28-30 

4. Actinofels and actinoschist interlayered with amphibolite 

and serpentinite 

5. Green 

9. In thrust-fault contact with Loch Raven Schist, Oella and 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Sykesville Formations (Wissahickon Group); underlies Mount 

Washington Amphibolite (Baltimore Mafic Complex) in E-W 

anticline which is truncated on SE by James River Formation 

10. Type locality: Exposures at abandoned Hollofield Quarry 

along E bank of Patapsco River, 80 m S of first bridge 

crossing the Patapsco N of U.S. Righway I-7n. Ellicott City 

quadrangle, Howard County, Md. 

Holly Corner Gneiss (Fredericksburg Complex) 

1. Early Cambrian(?) 

2. Virginia (EC) 

3. Pavlides, Louis, 1980, Revrsed nomenclature and stratigraphic relationships of the Fredericksburg Complex and 

Quantico Formation of the Virginia Piedmont: U.S. Geol. 

Survey Prof. Paper 1146, p. 5, 7 

4. Amphibole-biotite gneiss 

5. Dark-gray to black 

7. Fine- to medium-grained, foliated; refolded synform structure 

9. Allochthonous equivalent of Ta River Metamorphic Suite and 

possibly an eastern distal facies of Chopawamsic Formation; 

intruded by Falls Run Granite Gneiss 

10. Type area: Along two intermittent streams that flow into 

Rappahannock River, S of Holly Corner crossroads, NC Salem 

Church quadrangle, Stafford County, Va. 

Home Station Member (Augusta Mountain Formation) 

1. Middle Triassic' (Ladinian) 

2. Nevada (NC) 

3. Nichols, K. M., and Silberling, ·N. J., 1977, Stratigraphy 

and depositional history of the Star Peak Group (Triassic), 

northwestern Nevada: Geol. Soc. America Spec. Paper 178, 

p. 23-25 

4. Interstratified primary dolomite, limestone, sandstone, and 

secondary dolomite 

5. Light-gray 

6. 250 m 7. Massive, saccharoidal, cliff-forming, supratidal deposits 

9. Disconformably overlies Fossil Hill Member (Favret Formation); transitionally underlies Panther Canyon Member 

(Augusta Mountain Formation) (both formations in Star Peak 

Group) 

10. Type section: RidgeS of Favret Canyon, T. 25 N., R. 39 E., 

N Augusta Mountains, Pershing County, Nev. Named for Home 

Station Ranch, 30 km NW of type section. 

Hominy Peak Fonaation (Absaroka Volcanic Supergroup) 

1. Eocene, middle 

2. Wyoming (NW) 

3. Love, J. D., Leopold, E. B., and Love, D. W., 1978, Eocene 

rocks, fossils, and geologic history, Teton Range, northwestern Wyoming: U.S. Geol. Survey Prof. Paper 932-B, p. 3-

31 

4. Volcaniclastic conglomerates, tuffs, quartzite conglomerates, andesite flows and breccia 

5. Green, brown, red 

6. 610 m 

7. Minor gold deposits; fossiliferous (pollen) 

75 
76 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Unconformably overlies Pinyon Conglomerate or older rocks; 

unconformably underlies Conant Creek Tuff (at type section) or Huckleberry Ridge Tuff; intruded by late Eocene dacite 

porphyry of Birch Hills 

Type section: Exposures 0.8 km S of Hominy Peak on SEfacing escarpment of Hominy Ridge on NW margin of Conant 

basin, SE1/4 sec. 16 and N1/2 sec. 21, T. 47 N., R. 117 w., 

Grassy Lake Reservoir quadrangle, Teton County, Wyo. 

Honey Formation (Packsaddle Group) 

1. Precambrian 

2. Texas (C) 

3. McGehee, R. V., 1979, Precambrian rocks of the southeastern 

Llano region, Texas: Texas Bur. Econ. Geology Geol. Circ. 

79-3, p. 8-9 

4. Graphite schist, calc-silicate rock, marble 

6. 2,530 m (composite) 

9. Overlies Valley Spring Gneiss (Llano Supergroup); underlies 

Sandy Formation (Packsaddle Group). Unit was formerly Honey 

Creek Member (Packsaddle Formation) of McGehee (1964) 

10. Type locality: Base exposed in Honey Creek, NW of Packsaddle Mountain, Cap Mountain quadrangle; upper part exposed 

along Sandy Creek from State Highway 71 bridge to mouth of 

creek, Dunman Mountain quadrangle, Llano County, Tex. 

Hook Mountain Basalt (Newark Supergroup) 

1. Early Jurassic 

2. New Jersey (NE) 

3. Olsen, P. E., 1980, The latest Triassic and Early Jurassic 

formations of the Newark Basin (eastern North America, 

Newark Supergroup)--stratigraphy, structure, and correlation: New Jersey Acad. Sci. Bull., v. 25, no. 2, p. 37-38 

4. Two massive basalt flows with interbedded thin pahoehoe 

flows 

6. 110 m 9. Overlies Towaco ·Formation; underlies Boonton Formation. 

Unit was formerly "third" Watchung Basalt of Darton (1890) 

10. Type section: Cuts along Hook Mountain Road and U.S. Interstate Highway 80 through S terminus of Hook Mountain near 

Pine Brook, Morris County, N.J. 

Hope Member (Rickenbach Formation) 

1. Early Ordovician 

2. New Jersey (NC) 

3. Markewicz, F. J., and Dalton, Richard, 1977, Stratigraphy 

and applied geology of the lower Paleozoic carbonates in 

northwestern New Jersey--Field Conference of Pennsylvania 

Geologists, 42d, Stroudsburg, 1977, Guidebook: [Harrisburg, 

Pennsylvania Geol. Survey] p. 17 

4. Dolomite with chert beds 

5. Gray to dark-gray 

6. 51 m 7. Aphanitic to coarsely crystalline, medium- to massivebedded, with internal brecciation 

9. Overlies lower member of Rickenbach Formation; underlies 

Branchville Member (Epler Formation); intertongues with 

informal Crooked Swamp dolomite facies (Rickenbach Formation), which is well developed N of Lafayette, Sussex 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

County, N.J. 

10. Type section: On U.S. Highway I-80 near New Jersey County 

Route 521 exit, N of Hope, Warren County, N.J. 

Hopukani Formation (Hamakua Group) 

1. Pleistocene 

2. Hawaii (SE) 

3. Porter, S. c., 1979, Quaternary stratigraphy and chronology 

of Mauna Kea, Hawaii--a 380,000-yr record of mid-Pacific 

volcanism and ice-cap glaciation: Geol. Soc. America Bull. 

(pt. 2, microfiche), v. 90, no. 7, p. 988-998 

4. Alkalic olivine basalt lava with olivine phenocrysts 

6. 30 m 

7. Thin-bedded vesicular pahoehoe flows and cinder cones 9. Overlies volcanic rocks of Hamakua Group (lower member of 

Hamakua volcanic series of Stearns and Macdonald (1946), not 

renamed here); underlies Pohakuloa Formation (Hamakua Group) or basal lavas of Laupahoehoe Group. Equivalent to upper 

member of Hamakua volcanic series of Stearns and Macdonald 

(1946) 

10. Type section: Along State Highway 19 on S wall of Laupahoehoe Gulch, between 100 and 130 m altitude, Mauna Kea 

volcano, Hawaii County, Hawaii. Named for nearby Hopukani 

Springs. 

Horseshoe Formation 

1. Late Cretaceous 

2. Idaho (SE) 

3. Entzminger, D. J., 1979, Revision of Upper Cretaceous stratigraphy--Big Hole Mountains, Idaho: Earth Sci. Bull., v. 

12, no. 4, p. 20-22 

4. Sandstone, shale, coal 

5. Brown, gray, green 

6. Range 340-400 m 

7. Persistent fossil bed (mollusk fragments) 

8. In western coal belt, informal subdivisions include twelve 

named coal beds and Brown Bear leader sandstone, the lowest 

massive sandstone bed 

9. Gradationally overlies Bacon Ridge Formation; underlies 

unnamed unit 

77 

10. Composite section: Compiled from four sections in Horseshoe 

Creek area, including measured surface section on ridge N of 

Horseshoe Creek and two subsurface sections from Phillips 

Horseshoe No. 1 well and Sunmark-Supron Miner Estate 4-34 

well, T. 5 N., R. 44 E., Big Hole Mountains, Garns Mountain 

quadrangle, Teton County, Idaho. 

Hoyt Canyon Formation 

1. Late Triassic 

2. Nevada (WC) 

3. Speed, R. C., 1976, Geologic map of the Humboldt lopolith 

and surrounding terrane, Nevada: Geol. Soc. America Map and 

Chart Ser. MC-14, p. 2 

4. Alternating micritic limestone and slaty silty mudstone, 

siltstone, and minor sandstone 

5. Black 

6. 500 m 

1. Thin-bedded 
78 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Conformably overlies Bernice Formation; conformably underlies Mud Springs Canyon Formation 

Type locality: Not stated. Probably named for exposures in 

Hoyt Canyon, sees. 10 and 11, T. 22 N., R. 37 E., Clan 

Alpine Mountains, Churchill County, Nev. 

Huber Formation 

1. Paleocene and Eocene, early(?) and middle 

2. Georgia (C) 

3. Buie, B. F., 1978, The Huber Formation of eastern central 

Georgia: Georgia Geol. Survey Bull. 93, p. 1-7 

4. Sand and kaolin with bauxite beds 

5. White to cream, buff, gray 

6. 10.2 m, range <1-28.7 m 1. Sand medium- to very coarse grained, crossbedded; kaolin in 

beds, tubular forms, and balls; fossiliferous 

9. Unconformably overlies undifferentiated Cretaceous strata; 

unconformably underlies Clinchfield Sand, Tivola Limestone, 

or Barnwell Formation 

10. Type locality: Exposures from vicinity of Dry Branch and 

Stone Creek Church, SE for 8 km to Flat Creek, Twiggs 

County, Ga. Named for Huber Post Office. 

Huntington Formation 

1. Late Triassic 

2. Oregon (EC) 

3. Brooks, H. C., 1979, Geologic map of the Huntington and part 

of the Olds Ferry quadrangles, Baker and Malheur Counties, 

Oregon: Oregon Dept. Geology and Mineral Industries Geol: 

4. 

6. 

7. 

9. 

10. 

Huntley 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Map Ser. GMS-13 

Volcanic agglomerate, tuff, and flows intercalated with coarse volcaniclastic breccia and conglomerate and minor 

sedimentary rocks 

Range 3,000->6,000 m Bedded sequences of fine-grained sedimentary rocks; shallow 

intrusive bodies; zeolite and greenschist facies, abundant 

structural disruptions; fossiliferous (ammonites) 

Unconformably underlies Jet Creek Member (Weatherby Formation); base not exposed 

Type locality: Along Burnt River and Snake River, Tps. 13 

and 14 S., Rs. 44 and 45 E., Baker County, Oreg. Named for 

town in EC Huntington quadrangle. 

Mountain Formation 

Late Devonian and Early Mississippian 

Pennsylvania (NC) 

Berg, T. M., and Edmunds, W. E., 1979, The Huntley Mountain 

Formation--Catskill-to-Burgoon transition in north-central 

Pennsylvania: Pennsylvania Geol. Survey, 4th ser., Inf. 

Circ. 83, p. 1-80 

Sandstone, with minor siltstone, shale, and conglomerate 

Greenish-gray to light-olive-gray 

170 m Nonmarine clastic succession; fining-upward cycles in lower 

part; crossbedded 

Transitionally overlies Catskill Formation; transitionally 

underlies Burgoon Sandstone 

Type section: Exposure on SE slope of Huntley Mountain, NW 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

of village of Waterville, between lat 41°19'09" N., long 

7P22'20" W. (top) and lat 41°18'35" N., long 77°21'19" W. 

(base), Waterville quadrangle, Lycoming County, Pa. 

Bu-pwi Rhyodacite 

1. Miocene 

2. Nevada (WC) 

3. Ekren, E. B., and others, 1980, Stratigraphy, preliminary 

petrology, and some structural features of Tertiary volcanic 

rocks in the Gabbs Valley and Gillis Ranges, Mineral County, 

Nevada: U.S. Geol. Survey Bull. 1464, p. 36-41 

4. Rhyodacite tuff and lava, flow breccia 

5. Gray, brown, black 

6. >1 ,000 m 

7. Porphyritic, cooling units 

8. Nugent Tuff Member, Ghost Dance Lava Member, informal intermediate lavas of Poinsettia Spring area probably coeval with 

Ghost Dance, and Poinsettia Tuff Member 

9. Overlies Blue Sphinx Tuff or lava of Nugent Wash; underlies 

lava of Mount Ferguson or tuff of Copper Mountain 

10. Type locality: Exposures near Hu-pwi Wash, T. 12 N., 

R. 30 E., N Gillis Range, Mineral County, Nev. 

Hyak Member (Lakedale Drift) 

1. Pleistocene 

2. Washington (C) 

3. Porter, S. C., 1976, Pleistocene glaciation in the southern 

part of the North Cascade Range, Washington: Geol. Soc. 

America Bull. v. 87, no. 1, p. 71 

4. Till, lacustrine sediments 

7. Moraines, outwash fill 

8. Till and outwash facies 

9. Overlies Domerie Member (Lakedale Drift); underlies Holocene 

alluvium 

10. Type locality: Till facies: roadcuts along U.S. Highway 

I-90, NW1/4NW1/4 sec. 15, T. 22 N., R. 11 E.; outwash 

facies: cutbank along Coal Creek near town of Hyak, 

NW1/4SE1/4 sec. 15, T. 22 N., R. 11 E., Kittitas County, 

Wash. 

Hydes Marble Member (Loch Raven Schist) 

1. Cambrian-Ordovician(?) 

2. Maryland (NC) 

3. Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the eastern Maryland Piedmont: Maryland Geol. Survey Rept. Inv. 27, 

p. 10, 24 

4. Metalimestone, metadolostone, calc-silicate fels 

5. White 

6. Range <1-300 m 9. Lens within main body of Loch Raven Schist 

10. Type locality: Not established because of paucity of 

outcrop and heterogeneous nature of rock types. Named for 

village of Hydes, EC Baltimore County, Md. 

Ibex Member (Ely Springs Dolostone) 

1. Late Ordovician 

2. Utah (WC), Nevada 

79 
80 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Budge, D. R., and Sheehan, P. M., 1980, The Upper Ordovician 

through Middle Silurian of the eastern Great Basin--Pt. 1, 

Introduction--historical perspective and stratigraphic synthesis; Pt. 2, Lithologic descriptions: Milwaukee Public 

Mus. Contr. Biology and Geology, no. 28, p. 13-15 (pt. 1); no. 29, p. 22 (pt. 2) 

Dolomite containing frosted quartz sand grains 

Grayish-black, gray, brownish-black 

9.5 m 

Microcrystalline to finely crystalline, thin- to thickbedded 

Underlies Barn Hills Member (Ely Springs Dolostone); overlies Eureka Quartzite 

Exposures 3.2 km NNW of Ibex Well bench mark 4779, 

SE1/4NW1/4 sec. 26, T. 21 s., R. 14 W., Barn Hills, Confusion Range, Millard County, Utah. 

Ice Harbor Member (Saddle Mountains Basalt) 

1. Miocene, late 

2. Washington (SE) 

3. Swanson, D. A., and others, 1979, Revisions in stratigraphic 

nomenclature of the Columbia River Basalt Group: U.S. Geol. 

Survey Bull. 1457-G, p. G51-G53 

4. Basalt 

6. Range 15-30 m 7. At least three thick flows, with thin flows and tephra 

8. Informal basalt of Basin City, basalt of Martindale, and 

basalt of Goose Island 

9. Unconformably overlies Elephant Mountain Member; underlies 

alluvial deposits; apparently older than Lower Monumental 

Member 

10. Type locality: Abandoned quarry on S side of Snake River 

2.6 km W of Ice Harbor Dam, SE1/4SE1/4 sec. 22, T. 9 N., 

R. 31 E., Humorist quadrangle, Walla Walla County, Wash. 

Imnaha Basalt (Columbia River Basalt Group) 

1. Miocene, early 

2. Oregon (NE), Idaho, Washington 

3. Swanson, D. A., and others, 1979, Revisions in stratigraphic 

nomenclature of the Columbia River Basalt Group: U.S. Geol. 

Survey Bull. 1457-G, p. G8-G12 

4. Plagioclase-phyric basalt 

6. 500 m 1. Coarse-grained, 14 flows, weathers to grus-covered slopes 

9. Unconformably overlies pre-Tertiary rocks; conformably 

underlies Grande Ronde Basalt (Yakima Basalt Subgroup of 

Columbia River Basalt Group) 

10. Type locality: Exposures in cliffs on W side of Snake River 

above N end of Dug Bar, near mouth of Imnaha River, Cactus 

Mountain quadrangle, Wallowa County, Oreg. 

Indian John Member (Kittitas Drift) 

1. Pleistocene 

2. Washington (C) 

3. Porter, S. C., 1976, Pleistocene glaciation in the southern 

part of the North Cascade Range, Washington: Geol. Soc. 

America Bull., v. 87, no. 1, p. 67-69 

4. Gravel, till 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

6. 100 m 

1. Moraines, outwash 

8. Till and outwash facies 

9. Overlies Swauk Prairie Member (Kittitas Drift); underlies 

Lakedale Drift 

10. Type locality: Till facies: $ide of Ino~n John Hill at 

635 malt., NW1/4SW1/4 sec. 3, T. 19 N., R. 16 E., outwash 

facies: borrow pit on N side of Indian John Hill, 

NW1/4SE1/4 sec. 3, T. 19 N., R. 16 E., upper Yakima River 

drainage basin, Kittitas County, Wash. 

Indian Well Formation 

1. Oligocene 

2. Nevada (NE) 

3. Smith, J. F., Jr., and Ketner, K. B., 1976, Stratigraphy of 

post-Paleozoic rocks and summary of resources in the CarlinPinon Range area, Nevada: U.S. Geol. Survey Prof. Paper 

867-B, p. B23-B28 

4. Tuffaceous sandstone, limestone, and conglomerate, tuff, and 

ash-flow tuff 

5. Tan, gray, white 

6. 1,015 m 1. Interlayered; sedimentary rocks of lacustrine and fluviatile 

origin 

8. Four informal units 

9. Unconformably overlies older Tertiary (including Elko Formation), Jurassic, and Paleozoic rocks; unconformably underlies Quaternary alluvium or locally underlies younger 

Tertiary rocks (including Humboldt Formation) 

10. Composite type section: Sees .. 2 and 3, T. 30 N., R. 54 E., 

sec. 25, T. 31 N., R. 54 E., and sees. 29 and 30, T. 31 N., 

R. 55 E., Dixie Flats quadrangle, Elko County, Nev. Named 

for a water well in SE1/4 sec. 30, T. 31 N., R. 55 E. 

Intracoastal Formation 

1. Miocene, middle, to Pliocene, late 

2. Florida (NW) 

3. Schmidt, Walter, and Clark, M. W., 1980, Geology of Bay 

County, Florida: Florida Bur. Geology Bull. 57, p. 44-54 

4. Argillaceous, calcarenitic, sandy limestone 

5. Gray, olive-green 

6. 49 m, range <1-73 m 

1. Poorly consolidated, microfossiliferous, subsurface; missing 

biostratigraphic zones indicate late Miocene-early Pliocene 

hiatus 

9. Unconformably overlies Bruce Creek Limestone; underlies or interfingers with Jackson Bluff Formation or unconformably 

underlies Pliocene to Holocene sands 

10. Type section: Intracoastal Waterway core No. 1 (W-8873), 

depth-interval 20-69 m, NE1/4SW1/4 sec. 11, T. 3 S., 

R. 18 W., Walton County, Fla. 

Intricate Basalt 

1. Pliocene(?) 

2. Alaska (C) 

3. Detterman, R. L., and Reed, B. L., 1980, Stratigraphy, 

structure, and economic geology of the Iliamna quadrangle, 

Alaska: U.S. Geol. Survey Bull. 1368-B, p. B58-B59 

81 
82 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Olivine-augite basalt 

Black to dark-green 

Range 100-150 m 

Glassy to porphyritic, columnar jointing 

Disconformably to unconformably overlies Gibraltar Lake Tuff 

and all other Tertiary rocks; underlies Quaternary surficial 

deposits 

Type locality: Exposures around Intricate Bay, at SE end of 

Iliamna Lake, Iliamna quadrangle, Alaska Peninsula, Alaska. 

Ironshire Formation 

1. Pleistocene (Sangamonian) 

2. Maryland (SE), Delaware, Virginia 

3. Owens, J. P., and Denny, C. S., 1979, Upper Cenozoic 

deposits of the central Delmarva Peninsula, Maryland and 

Delaware: U.S. Geol. Survey Prof. Paper 1067-A, p. A20-A22 

4. Sand, gravelly sand 

5. Pale-yellow to white, with layers of black minerals 

6. 7.6 m, range <7-33 m 7. Coarsens upward; crossbedded, fluviatile-estuarine channel 

fill and beach sand 

9. Unconformably overlies Beaverdam Sand or Omar Formation 

against E-facing scarp 

10. Type locality: Borrow pits near Ironshire, Delmarva Peninsula, Worcester County, Md. 

Jabez Sandstone Member (Fort Payne Formation) 

1. Early Mississippian 

2. Kentucky (SC) 

3. Kepferle, R. C., and others, 1980, Jabez Sandstone Member--a 

new member of the Fort Payne Formation (Mississippian), 

south-central Kentucky: U.S. Geol. Survey Bull. 1502-A, p. 

A104-A107 

4. Sandstone 

5. Gray to yellowish-gray, weathers brownish red 

6. 43 m max 7. Medium-grained, angular, well-sorted, planar-bedded, NWtrending prism of vertically stacked coalescing tongues 

9. Overlies and intercalated with limestone and dolosiltite of 

lower part of Fort Payne Formation; intercalated with Cane 

Valley Limestone Member (Fort Payne Formation); underlies 

Salem and Warsaw Formations 

10. Type section: S shore of Lake Cumberland near mouth of 

Harmon Creek, lat 36°55'20" N., long 84°57'15" W., Jabez 

quadrangle, Wayne County, Ky. Named for exposures 6.5 km SW 

of town of Jabez. 

Jam Brook Formation 

1. Cambrian or Ordovician 

2. Maine (SC) 

3. Bickel, C. E., 1976, Stratigraphy of the Belfast quadrangle, 

Maine: Geol. Soc. America Mem. 148, p. 116-119 

4. Quartz-mica schist; calc-silicate gneiss, schist, and phyllite; quartzite; quartz-pebble metaconglomerate; marble 

6. <1,000 m 7. Marine transgressive sequence 

B. Five informal map units reflecting lithology 

9. In fault contact with Penobscot Formation to SE along 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

inferred thrust, and with Appleton Ridge-Formation to NW 

along St. George fault. Unit was formerly informal St. 

George Formation of Cheney (1967) 

10. Type area: Jam Brook, SW Belfast quadrangle, Waldo County, 

Maine. 

Jansen Creek Heaber (Makah Formation) 

1. Oligocene, early 

2. Washington (NW) 

3. Snavely, P. D., Jr., and others, 1980, Makah Formation--a 

deep-marginal-basin sequence of late Eocene and Oligocene 

age in the northwestern Olympic Peninsula, Washington: U.S. 

Geol. Survey Prof. Paper 1162-B, p. 14-15 

4. Basaltic sandstone and conglomerate 

6. 200 m 

7. Deformed, thick-bedded, fossiliferous, shallow-water olistostrome deposits, cliff-forming 

9. Lies 250 m above Third Beach Member; overlies and underlies, 

with sharp contacts, unnamed undeformed deep-water marine 

strata of Makah Formation 

10. Type section: Sea cliffs, wave-cut platforms, and sea 

stacks from headland 0.5 km E of Bullman Creek to point 0.7 

km SE of Brush Point, NE1/4NW1/4 sec. 6, T. 32 N., R. 13 W., 

Strait of Juan de Fuca, Clallam County, Wash. Named for 

exposures at mouth of Jansen Creek, SE1/4SE1/4 sec. 26, 

T. 33 N. , R. 14 W. 

Jaycox Shale Member (Ludlowville Formation) 

1. Middle Devonian 

2. New York (WC) 

3. Baird, G. C., 1979, Sedimentary relationships of Portland 

Point and associated Middle Devonian rocks in central and 

western New York: New York State Mus. Bull. 433, p. 14-19, 

4. 

5. 

6. 

7. 

9. 

10. 

Jemtland 

1 • 

2. 

3. 

4. 

6. 

7. 

9. 

23 

Calcareous shale with basal muddy limestone 

Light-colored, gray 

3.6 m, range 0.48-16.00 m 

Fossiliferous 

Equivalent to upper part of King Ferry Shale Member (Ludlowville Formation) E of Seneca Lake; overlies Wanakah Shale 

Member (Ludlowville Formation); paraconformably underlies 

Tichenor Limestone Member (Moscow Formation) 

Type section: Exposures in three waterfalls and banks along 

S branch of Jaycox Creek, 3.2 km NNE of Geneseo and 400 m W 

of New York Route 39, Geneseo quadrangle, Livingston County, 

N.Y. 

Formation (Perham Group) 

Silurian (late Wenlockian and early Ludlovian) 

Maine (NE) 

Roy, D. C., and Mencher, Ely, 1976, Ordovician and Silurian 

stratigraphy of northeastern Aroostook County, Maine: Geol. 

Soc. America Mem. 148, p. 39-41, 50 

Interlayered silty shale, shale, and calcareous and lithic 

graywacke 

Range 610-850 m Fine- to coarse-grained, thin-bedded 

Conformably overlies Frenchville Formation and New Sweden 

83 
84 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Formation (Perham Group); conformably underlies Fogelin Hill 

Formation 

Type area: Exposures along Maine Route 161 in Jemtland, 

Aroostook County, Maine. 

Jericho 

1. 

2. 

3. 

Run Meaber (Beaufort Formation) 

Paleocene, early (Danian) 

North Carolina (EC) 

Brown, P. M., and others, 1977, Wrench-style deformation in 

rocks of Cretaceous and Paleocene age, North Carolina 

coastal plain: North Carolina Div. Earth Resources Spec. 

Pub. 5, p. 13-14, 39-40 

4. 

5. 

6. 

7. 

9. 

10. 

Jet Creek 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Siliceous mudstone with basal conglomerate and chert and 

sandstone layers 

Black to gray 

Range 0.9-2. 7 m 

Friable to extremely hard; silicified microfossils poorly 

preserved 

Disconformably overlies Peedee Formation; unconformably 

underlies surficial material 

Type locality: Locality NC-LEN-0-8-73, exposures at and 

upstream from waterfall (on Jericho Run, tributary to Neuse 

River), in ravine extending back from Jericho Run fault 

scarp, 0.8 km NE of County Road 1809 (lat 35°19'14" N., 

long 77°29'43" W.) near Graingers, Lenoir County, N.C. 

Member (Weatherby Formation) 

Early Jurassic 

Oregon (EC) 

Brooks, H. c., 1979, Geologic map of the Huntington and part 

of the Olds Ferry quadrangles, Baker and Malheur Counties, 

Oregon: Oregon Dept. Geology and Mineral Industries Geol. 

Map Ser. GMS-13 

Pebble and cobble conglomerate, wacke, siltstone, limestone 

Red, green 

250 m 

Conglomerate composed of volcanic fragments; limestone, 

massive and thin-bedded; fossiliferous (ammonites) 

Unconformably overlies Huntington Formation; intergrades 

laterally with lower part of Weatherby Formation; upper and 

lower contacts obscured by landsliding 

Type section: Exposures near head of Jet [Jett on base map] 

Creek in sees. 16, 17, 18, 19, and 20, T. 13 S., R. 45 E., 

Baker County, Oreg. 

Jewell Bluff Formation (Stones River Group) 

1. Middle Ordovician 

2. Tennessee (SC) 

3. Wilson, R. L., 1979, The stratigraphy of exposed rocks in 

Hamilton County, Tennessee: Tennessee Div. Geology 

Bull. 79, p. 23-25 

4. Limestone, siltstone 

5. Gray, greenish-gray, reddish-gray 

6. 104 m 

7. Thin- to medium-bedded 

8. Informal lower and upper members 

9. Unconformably overlies Mascot Dolomite (Knox Group); 

conformably underlies Carters Limestone (Stones River Group) 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

10. Type section: Exposures in Jewell Bluff, on N side of 

Hiwassee River across from mouth of Gunstocker Creek, Meigs 

County, Tenn. 

Johnson Member (Snake Creek Formation) 

1. Miocene, late 

2. Nebraska (NW) 

3. Skinner, M. F., Skinner, S.M., and Gooris, R. J., 1977, 

Stratigraphy and biostratigraphy of late Cenozoic deposits 

in central Sioux County, western Nebraska: Am. Mus. Nat. 

History Bull., v. 158, art. 5, p. 311-314 

4. Sand and gravel with sedimentary and granite clasts in lower 

part, sand and clay in upper part 

6. 21 m; range 2-21 m 

7. Unconsolidated, stream-channel deposits, fossiliferous 

(vertebrates) 

9. Overlies Sheep Creek Formation (Hemingford Group) with 

erosional unconformity, or locally overlies slump blocks of 

Murphy Member; uppermost member of Snake Creek Formation 

(Ogallala Group); underlies sand and sod at surface 

10. Type section: Near head of East Pliohippus Draw, NE1/4NW1/4 

sec. 32, and SE1/4SW1/4 sec. 29, T. 26 N., R. 55 W., Sioux 

County, Nebr. Named for Vance Johnson Ranch. 

Jones Falls Schist 

1. Cambrian(?) 

2. Maryland (NC) 

3. Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the eastern Maryland Piedmont: Maryland Geol. Survey Rept. Inv. 27, 

p. 13, 15 

4. Biotite-plagioclase-muscovite-quartz schist 

6. Range <1-250 m 

7. Medium- to coarse-grained 

9. Overlies Relay Gneiss Member, Carroll Gneiss Member, or Druid Hill Amphibolite Member (James Run Formation) in NE-SW 

syncline 

10. Type locality: Outcrops along Jones Falls, E of Druid Hill 

Park between Falls Road and 28th Street ramps onto Jones 

Falls Expressway, Baltimore City, Baltimore County, Md. 

Joy Tuff 

1 • 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

Eocene, late, and Oligocene, early 

Utah (WC) 

Lindsey, D. A., 1979, Geologic map and cross-sections of 

Tertiary rocks in the Thomas Range and northern Drum Mountains, Juab County, Utah: U.S. Geol. Survey Misc. Inv. Ser. 

Map I-1176 

Rhyolitic ash-flow tuff with crystals of quartz, sanidine, 

plagioclase, and biotite 

Lower member: gray-pink to red-brown; upper member: gray 

to black 

Lower member: 180 m; upper member: 20 m Lower member: moderately welded, forms cliffs; upper 

member: densely welded 

Informal lower crystal tuff member and upper black glass 

tuff member 

Unconformably overlies Mount Laird Tuff, Drum Mountains 

85 
86 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Rhyodacite, or Paleozoic rocks; underlies informal Oligocene(?) megabreccia of northern Drum Mountains, or uncon- formably underlies Topaz Mountain Rhyolite or Quaternary 

sediments 

Type locality: Exposures NW of Joy townsite, sees. 16, 17, 

and 22, T. 14 s., R. 11 W., Drum Mountains, Juab County, 

Utah. 

Juniper Gulch Meaber (Snaky Canyon Formation) 

1. Late Pennsylvanian (Missourian and Virgilian) and Early 

Permian (Wolfcampian) 

2. Idaho (SE) 

3. Skipp, Betty, and others, 1979, Upper Paleozoic carbonate 

bank in east-central Idaho--Snaky Canyon, Bluebird Mountain, 

and Arco Hills Formations, and their paleotectonic significance: U.S. Geol. Survey Bull. 1486, p. 29-32 

4. Interbedded sandy and cherty limestone and dolomite 

5. Weathers light gray 

6. 597 m 

7. Thin- to thick-bedded, oolitic, 9 m thick, ledge-forming 

dolomite marker bed, fossiliferous 

9. Gradationally overlies Gallagher Peak Sandstone Member 

(Snaky Canyon Formation); conformably underlies Phosphoria 

Formation 

10. Type section: Exposures on Gallagher Peak, sec. 21, 

T. 9 N., R. 32 E., Copper Mountain quadrangle, Clark County, 

Idaho. Named for Juniper Gulch, about 1 km S of type 

section. 

Kakhonak Complex 

1. Permian(?), Triassic, and Jurassic 

2. Alaska (C) 

3. Detterman, R. L., and Reed, B. L., 1980, Stratigraphy, 

structure, and economic geology of the Iliamna quadrangle, 

Alaska: U.S. Geol. Survey Bull. 1368-B, p. B6-B9 

4. Metamorphic rocks mainly of greenschist facies, including 

argillite, schist, and quartzite; locally of pyroxenehornfels, amphibolite, and granulite facies 

6. >1,000 m 

7. Roof pendants in Alaska-Aleutian Range batholith; complexly 

faulted and folded 

9. Locally, apparently conformably, overlies Cottonwood Bay 

Greenstone; interbedded with and overlain by metavolcanic 

rocks; intruded by Jurassic rocks-of Alaska-Aleutian Range 

batholith 

10. Type locality: Exposures along Kakhonak Lake, SE of Iliamna 

Lake, Iliamna quadrangle, Alaska Peninsula, Alaska. Named 

for Kakhonak Lake, River, and Bay. 

~ent Island Formation 

1. Pleistocene (Wisconsinan) 

2. Maryland (EC), Delaware 

3. Owens, J. P., and Denny, C. s., 1979, Upper Cenozoic 

deposits of the central Delmarva Peninsula, Maryland and 

Delaware: U.S. Geol. Survey Prof. Paper 1067-A, p. A24-A26 

4. Sand, clay-silt, gravel 

5. Light-colored 

6. 12 m max 
7. 

9. 

10. 

Kimball 

1 • 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Crossbedded; tree stumps in growth position encased within 

clay-silt, estuarine deposit 

Unconformably overlies Chesapeake Group, undivided, 

Pensauken Formation, Beaverdam Sand, and equivalents of 

Ironshire and Omar Formations 

Type area: Exposures in bluffs on N side of Kent Island 

Formations, along Chester River, Queen Annes County, Md. 

Corners Conglomerate 

Late Proterozoic or Cambnian 

New York (EC) 

Fisher, D. w., 1980, Bedrock geology of the central Mohawk 

Valley, New York: New York State Mus. Map and Chart 

Ser. 33, Eastern Sheet 

Meta-quartzite clasts in coarse quartz sand matrix, sandstone lens 

Grayish-white, weathers yellow, orange, brown 

0-3 m 

Cobble- to boulder-size clasts, iron-stained 

Overlies biotite gneiss; Irving Pond Formation exposed 

nearby; may be equivalent to Potsdam Sandstone 

Type locality: Exposures along N side of New York 

Highway 29, 0.55 km E of Kimball Corners at intersection of 

New York Highways 29 and 147, Galway quadrangle, Saratoga 

County, N.Y. 

87 

King Tonopah Member (Fraction Tuff) 

1. Miocene 

2. Nevada (C) 

3. Bonham, H. F., Jr., and Garside, L. J., 1979, Geology of the 

Tonopah, Lone Mountain, Klondike, and northern Mud Lake 

quads, Nevada: Nevada Bur. Mines and Geology Bull. 92, 

p. 51-54 

4. Vitric-lithic rhyolite ash-flow tuff with volcanic siltstone, sandstone, conglomerate, and breccia lenses 

6. 200 m 

7. Moderately to densely welded 

8. Two nearly identical cooling units 

9. Unconformably overlies Mizpah Formation, Tonopah Summit 

Member (Fraction Tuff); unconformably underlies Heller Tuff 

10. Type locality: Exposures extending from King Tonopah Mine, 

1.6 km N of town of Tonopah, for 1.6 km NE to top of "TV 

Tower Hill," sees. 24 and 25, T. 3 N., R. 42 E., Nye County, 

Nev. 

Kittitas Drift 

1. Pleistocene 

2. Washington (C) 

3. Porter, S. C., 1976, Pleistocene glaciation in the southern 

part of the North Cascade Range, Washington: Geol. Soc. 

America Bull., v. 87, no. 1, p. 66-69 

4. Till, gravel 

1. Moraines, dissected outwash fills; mantled by loess 

8. Swauk Prairie Member, Indian John Member 

9. Overlies Thorp Drift; underlies Lakedale Drift 

10. Type locality: Designated for each member. Named for 

Kittitas Valley, upper Yakima River drainage basin, Kittitas 

County, Wash. 
88 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Klaohopis Point Member (Makah Formation) 

1. Eocene, late 

2. Washington (NW) 

3. Snavely, P. D., Jr., and others, 1980, Makah Formation--a 

deep-marginal-basin sequence of late Eocene and Oligocene 

age in the northwestern Olympic Peninsula, Washington: U.S. 

Geol. Survey Prof. Paper 1162-B, p. 13 

4. Micaceous sandstone with siltstone interbeds and calcareous 

concretions 

6. 73 m 

7. Thick-bedded, amalgamated turbidite beds, ridge-forming 

9. Lies 155 m above Dtokoah Point Member and 290 m below Third 

Beach Member; gradationally overlies unnamed siltstone of 

Makah Formation; upper contact covered 

10. Type section: Wave-cut platform and headland exposures at 

Klachopis Point E of Neah Bay, NE1/4SE1/4 sec. 12, T. 33 N., 

R. 15 W., Strait of Juan de Fuca, Clallam County, Wash. 

~umu111ah1 Formation 

1. Pleistocene 

2. Hawaii (EC) 

3. Macdonald, G. A., 1978, Geologic map of the crater section 

of Haleakala National Park, Maui, Hawaii: U.S. Geol. Survey 

Misc. Inv. Ser. Map I-1088, p. 5 

4. Alkali olivine basalt 

7. Thin-bedded pahoehoe and aa lava flows; many small white 

feldspar phenocrysts 

9. Lower contact not exposed; unconformably underlies Kula 

Formation 

10. Type locality: Exposures at base of S wall of Haleakala 

Crater N and NE of Kumuiliahi, Haleakala National Park, SE 

Maui, Maui County, Hawaii. 

Kurry Creek Member (Doyle Creek Formation) 

1. Late Triassic 

2. Idaho (WC) 

3. Vallier, T. L., 1977, The Permian and Triassic Seven Devils 

Group, western Idaho and northwestern Oregon: U.S. Geol. 

Survey Bull. 1437, p. 45-48 

4. Conglomerate interlayered with sandstone, tuff, shale, 

argillite, and limestone 

5. Dark-brown to greenish-black 

6. >270 m 

7. Mainly clastic rock sequence within upper part of Doyle 

Creek Formation; thick-bedded, crudely graded, shallow 

marine fan deposit 

9. Conformably(?) overlies Wild Sheep Creek Formation; unconformably underlies Coon Hollow Formation or, locally, Martin 

Bridge Limestone. Unit was formerly Pittsburg Formation of 

W. R. Wagner (1945) 

10. Type section: Spur SE of West Creek, from 465 m elevation 

to top of ridge, NE1/4SE1/4 sec. 29 to SW1/4 sec. 28, 

T. 27 N., R. 1 W., Idaho County, Idaho. Named for nearby 

Kurry Creek. 

~uskulana Pass Formation 

1 . Early Cretaceous (Hauterivian and Barremian) 

2. Alaska (EC) 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

3. MacKeve~t, E. M., Jr., and others, 1978, Geologic map of the 

McCarthy C-8 quadrangle, Alaska: u.s. Geol. Survey Geol. 

Quad. Map GQ-1418 

4. Sandstone, siltstone, minor shale 

5. Dark-greenish-gray or medium-gray; weathers brown 

6. 300 m 

7. Thin-bedded, fine- and very fine grained, meagerly fossiliferous, shallow marine deposits 

9. Gradationally overlies Berg Creek Formation; disconformably, 

or with slight angular unconformity, underlies Kennicott 

Formation 

10. Type section: Exposures extending S from NE1/4SE1/4SW1/4 

sec. 32, T. 3 s., R. 10 E., to NE1/4SW1/4NW1/4 sec. 5, 

T. 4 S., R. 10 E., upper drainage basin of Trail and Slatka 

Creeks, near Kuskulana Pass, McCarthy c-8 quadrangle, 

Wrangell Mountains, Alaska. 

Lac ~ Croix Granite (Vermilion Granitic Complex) 

1. Late Archean 

2. Minnesota (NC) 

3. Southwick, D. L., and Sims, P. K., 1980, The Vermilion 

Granitic Complex--a new name for old rocks in northern 

Minnesota: U.S. Geol. Survey Prof. Paper 1124-A, p. A5-A7 

4. Biotite granite 

5. Light-pink 

7. Homogeneous texture, weakly altered 

9. Grades into granite-rich migmatite and schist-rich migmatite 

10. Type area: Outcrops S of Lac La Croix, St. Louis County, 

Minn. Reference locality: Roadcuts along Echo Trail S of 

Little Indian Sioux River and E of Echo Lake, Shell Lake 

quadrangle. 

Ladron Member (Kelly Limestone) 

1. Early Mississippian (Osagean) 

2. New Mexico (WC) 

3. Armstrong, A. K., and Mamet, B. L., 1976, Biostratigraphy 

and regional relations of the Mississippian Leadville Limestone of the San Juan Mountains, southwestern Colorado: 

U.S. Geol. Survey Prof. Paper 985, p. 17-19 

4. Wackestone and packstone with nodular chert 

5. Gray 

6. 21.5 m 

7. Fossiliferous 

9. Disconformably overlies Caloso Member (Kelly Limestone); 

unconformably underlies Sandia Formation 

10. Type locality: Kelly Limestone type section on crest of 

Magdalena Mountains, NE1/4SW1/4 sec. 31, T. 2 S., R. 3 W., 

Socorro County, N. Mex. Named for Ladron Mountains, N of 

Magdalena Mountains. 

Lafayette 

1. 

2. 

3. 

Member (Epler Formation) 

Early Ordovician 

New Jersey (NC) 

Markewicz, F. J., and Dalton, Richard, 1977, Stratigraphy 

and applied geology of the lower Paleozoic carbonates in 

northwestern New Jersey--Field Conference of Pennsylvania 

Geologists, 42d, Stroudsburg, 1977, Guidebook: [Harrisburg, 

Pennsylvania Geol. Survey] p. 21 

89 
go 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Dolomite with shale and chert beds 

Black, gray, weathers orange gray 

Range 15-76 m 

Fine- to medium-grained, laminated, with breccia zones Overlies Big Springs Member (Epler Formation); underlies 

Beaver Run Member (Ontelaunee Formation) 

Type section: Not stated, although unit is described in 

measured sections. Probably named for town of Lafayette, 

Sussex County, N.J. 

Lake Angeline Till 

1. Holocene 

2. Wyoming (NC) 

3. Nelson, R. S., 1977, Glacial deposits of the Lake Angeline 

quadrangle, Bighorn Mountains, Wyoming: Earth Sci. Bull., 

v. 10, no. 1, p. 18 

4. Cobble and boulder till in sand matrix 

5. Pinkish-gray, weathers light gray 

6. Range 3-4 m 7. Angular boulders, very little matrix; loop moraines at 

mouths of cirques 

9. Overlies Chill Lakes Till 

10. Type locality: Moraine surrounding Lake Angeline, SE1/4 

sec. 16, T. 50 N., R. 85 W., Bighorn Mountains, Johnson 

County, Wyo. 

Lakedale Drift 

1. Pleistocene 

2. Washington (C) 

3. Porter, S. C., 1976, Pleistocene glaciation in the southern 

part of the North Cascade Range, Washington: Geol. Soc. 

America Bull., v. 87, no. 1, p. 70-72 

4. Till, gravel 

7. Moraines, outwash terraces; mantled by loess 

B. Bullfrog, Ronald, Domerie, and Hyak Members 

9. Overlies Kittitas Drift; underlies Holocene alluvium 

10. Type locality: Designated for each member. Named for 

community of Lakedale, upper Yakima River drainage basin, 

Kittitas County, Wash. 

Lake Durant Formation 

1. Proterozoic 

2. New York (NE) 

3. McLelland, James, and Isachsen, Yngvar, 1980, Structural 

synthesis of the southern and central Adirondacks--a model 

for the Adirondacks as a whole and plate tectonics interpretations: Geol. Soc. America Bull. (pt. 2, microfiche), v. 91, no. 2, p. 223-224, 233-234 

4. Granitic gneiss, interlayered with calc-silicate rocks near base 

5. Tan, pink, light-green 

6. Range 200-1,000 m 7. Characterized by lithologic consistency and areal continuity 

9. Overlies Cedar River Formation, underlies Blue Mountain Lake 

Formation 

10. Type locality: N of Lake Durant, 2.7 km S of Blue Mountain 

Lake on New York Route 28-30, Blue Mountain quadrangle, 

Hamilton County, N.Y. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Lake Merritt Member (Paluxy Sand?) 

1. Early Cretaceous 

2. Texas (C) 

3. Owen, M. T., 1979, The Paluxy Sand in north-central Texas: 

Baylor Geol. Studies Bull. 36, p. 8, 15-21 

4. Sand, silt, clay 

6. 6 m, range 3-6 m 

1. Horizontally bedded, tidal flat deposit 

9. Conformably overlies Glen Rose Limestone (Trinity Group); 

disconformably underlies Georges Creek Member (Paluxy Sand) 

10. Type locality: State Highway 16, 8.2 km NE of Goldthwaite, 

Mills County, Tex. Named for exposure near Lake Merritt, 

Mills County. 

Lamerdorf Tuff Member (Escalante Desert Formation) 

1. Oligocene 

2. Utah. (SW) 

3. Campbell, D. R., 1978, Stratigraphy of pre-Needles Range 

Formation ash-flow tuffs in the northern Needle Range and 

southern Wah Wah Mountains, Beaver County, Utah: Brigham 

Young Univ. Geol. Studies, v. 25, no. 3, p. 33-38 

4. Ash-flow tuff 

5. Pink, brown, lavender 

6. 109 m, range 21-109 m 

1. Moderately to densely welded, vitric 

8. Informal lower vitric-crystal tuff and upper vitric-lithic 

tuff 

9. Overlies tuff of Sulphur Spring; underlies Beers Spring 

Member (Escalante Desert Formation) 

10. Type locality: E of Willow Creek Spring and W and S of 

Bucket Ranch Spring, SE1/4 sec. 2, T. 29 s., R. 16 W., to 

S1/2 sec. 4, T. 29 s., R. 15 W., Wah Wah Mountains, 

Lamerdorf Peak quadrangle, Beaver County, Utah. 

Latigo Canyon Breccia Ma.ber (Calabasas Formation) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E23 

4. Sedimentary breccia 

6. 91 m 1. Clasts of red-bed (Sespe) sandstone and fossiliferous 

(Vaqueros) sandstone 

9. Overlies Escondido Canyon Shale Member (Calabasas 

Formation); intertongues with unnamed epiclastic volcanic 

breccia; underlies Solstice Canyon Tongue (Conejo Volcanics) 

10. Type area: Latigo Canyon, Santa Monica Mountains, EC Point 

Dume quadrangle, Los Angeles County, Calif. 

Latite Ridge Latite (Tintic Mountain Volcanic Group) 

1. Oligocene, middle 

2. Utah (C) 

3. Morris, H. T., and Lovering, T. S., 1979, General geology 

and mines of the East Tintic mining district, Utah and Juab 

Counties, Utah: U.S. Geol. Survey Prof. Paper 1024, p. 38-

40 

91 
92 

4. 

5. 

6. 

8. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Latite airfall and water-laid tuff and welded tuff 

Lower member: white; upper member: reddish-brown 

Lower member: range <1-30 m; upper member: range 38-152 m 

Informal lower airfall tuff member and upper welded tuff 

member 

Unconformably overlies Packard Quartz Latite or Copperopolis 

Latite (Tintic Mountain Volcanic Group); unconformably 

underlies Big Canyon Latite (Tintic Mountain Volcanic 

Group), or North Standard and Pinyon Queen Latites (Laguna 

Springs Volcanic Group), or disconformably underlies Pinyon 

Creek Conglomerate 

Type locality: Exposures on Latite Ridge, NW1/4 sec. 23, 

and NE1/4 sec. 27, T. 10 S., R. 2 W., East Tintic Mountains, 

16 km SW of East Tintic mining district, Juab County, Utah. 

Laucomer Member (Snake Creek Formation) 

1. Miocene, middle 

2. Nebraska (NW) 

3. Skinner, M. F., Skinner, S. M., and Gooris, R. J., 1977, 

Stratigraphy and biostratigraphy of late Cenozoic deposits 

in central Sioux County, western Nebraska: Am. Mus. Nat. 

History Bull., v. 158, art. 5, p. 310-311 

4. Quartz sand, gravel, fossil fragments, ash 

6. 14.3 m, range 1.2-14.3 m 

1. Unconsolidated, fluviatile, fossiliferous (vertebrates) 

9. Unconformably overlies Murphy Member; underlies soil at 

surface 

10. Type section: NE side of Olcott Hill, NE1/4SW1/4SE1/4 

sec. 3, T. 25 N., R. 55 W., near Laucomer Ranch, Sioux 

County, Nebr. 

Lawson Creek Formation 

1. Middle Proterozoic 

2. Idaho {C) 

3. Hobbs, S. W., 1980, The Lawson Creek Formation of Middle 

Proterozoic age in east-central Idaho: U.S. Geol. Survey 

Bull. 1482-E, p. 3-9 

4. Quartzite, siltstone, argillite 

5. Medium-reddish-purple, dark-purplish-gray, and maroon 

6. >1,300 m; total thickness unknown 

7. Predominantly thin-bedded, mud chip breccia, ripple marks, 

micaceous partings 

8. Informal basal quartzite transition zone, middle quartzite 

and silty argillite unit, upper argillite unit 

9. Conformably and gradationally overlies Swauger Formation; 

unconformably underlies Challis Volcanics 

10. Type locality: Exposures in Lost River Range where Lawson 

Creek flows into Pahsimeroi Valley, mostly in sees. 4 and 9, 

T. 14 N., R. 21 E., May quadrangle, Custer County, Idaho. 

Leesburg Limestone Conglaaerate Mellber (Bull Run Formation) 

1. Late Triassic 

2. Virginia (NE), Maryland 

3. Lee, K. Y., 1977, Triassic stratigraphy in the northern part 

of the Culpeper basin, Virginia and Maryland: U.S. Geol. 

Survey Bull. 1422-C, p. C6 

4. Limestone conglomerate, metamorphosed into marble where in 

contact with diabase 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

5. Gray 

7. 76 m, range 76-1,070 m 9. Overlies and intertongues with Balls Bluff Siltstone (Newark 

Group); underlies and intertongues with unnamed basalticflow-bearing clastics memb~r of Bull Run Formation {Newark 

Group) 

10. Type section: SE roadcuts at junction oYU.S. Route 15 

bypass and entrance road to Balls Bluff National Cemetery, 

SE Waterford quadrangle, Loudoun County, Va. Named for town 

of Leesburg. 

Lehigh Acres Member {Tamiami Formabion) 

1. Miocene, late 

2. Florida {SE) 

3. Peck, D. M., and others, 1979, Stratigraphy and paleoecology 

of the Tamiami Formation in Lee and Hendry Counties, 

Florida: Gulf Coast Assoc. Geol. Socs. Trans., v. 29, 

p. 331-333 

4. Limestone and calcareous sand, with minor clay and marl 

6. 18.5 m 

7. Highly porous and permeable shallow-water aquifer 

10. Type section: U.S.G.S. water test well L-1984, depthinterval 63.7-82.2 m, SW1/4NE1/4SE1/4 sec. 22, T. 46 s., 

R. 26 E., approx 1 km E of intersection of Alico Road and 

Corkscrew Road, Lee County, Fla. Named for nearby community 

of Lehigh Acres. 

Lenihan canyon Tuff 

1. Oligocene 

2. Nevada {WC) 4 

3. Bingler, E. C., 1978, Abandonment of the name Hartford Hill 

Rhyolite Tuff and adoption of new formation names for middle 

Tertiary ash-flow tuffs in the Carson City-Silver City area, 

Nevada: U.S. Geol. Survey Bull. 1457-D, p. D9-11 

4. Hornblende-biotite quartz latite tuff 

5. Pale-lavender-brown 

6. 300 m 

7. Moderately to strongly welded, mostly devitrified, finegrained, crystal-vitric; simple cooling unit 

9. Disconformably overlies Mickey Pass Tuff; unconformably 

underlies younger Tertiary rocks; older than Nine Hill Tuff 

10. Type section: Exposures 0.8 km NE of Lenihan Canyon, 

NE1/4NE1/4 sec. 14 T. 16 N., R. 20 E., Virginia City quadrangle, Storey County, Nev. 

Leopold Limestone Member (Branchville Formation) 

1. Late Mississippian (Chesterian) 

2. Indiana (SC) 

3. Gray, H. H., 1978, Buffalo Wallow Group--upper Chesterian 

(Mississippian) of southern Indiana: Indiana Geol. Survey 

Occasional Paper 25, p. 10 

4. Limestone with interbedded shale 

5. White to gray, weathers yellow brown 

6. 3.5 m 9. Conformably overlies shale of Branchville Formation; 

conformably underlies Tobinsport Formation 

10. Type section: Leopold Section, NW1/4 sec. 11 and SW1/4 

93 
94 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

sec. 2, T. 5 s., R. 2 W., W of Leopold along Indiana 

Route 37, Perry County, Ind. 

Lilesville Granite 

1. Late Mississippian and Early Pennsylvanian 

2. North Carolina (C) 

3. Waskom, J.D., and Butler, J. R., 1971, Geology and gravity 

of the Lilesville Granite batholith, North Carolina: Geol. 

Soc. America Bull., v. 82, no. 10, p. 2827-2844 

4. Adamellite, granodiorite, and tonalite 

7. Medium- to coarse-grained matrix, porphyritic rapakivi 

texture 

9. Intrudes metamorphosed volcanic rocks and argillites 

10. Type locality: Lilesville, Anson County, N.C. 

Limberlost Dolomite 

1. Middle Silurian 

2. Indiana (NE) 

3. Droste, J. B., and Shaver, R. H., 1976, The Limberlost 

Dolomite of Indiana--a key to the great Silurian facies in 

the southern Great Lakes area: Indiana Geol. Survey Occasional Paper 15, 21 p. 

4. Dolomite 

5. Brown, tan 

6. 5.5 m, range <1-21 m 

7. Fine- to medium-grained, oolitic, reef-bearing 

9. Conformably overlies Salamonie Dolomite; conformably underlies Waldron Formation 

10. Type section: John W. Karch Stone Co. quarry, SW1/4SW1/4 

sec. 31, T. 25 N., R. 15 E., near New Corydon, Adams County, 

Ind. Named for Limberlost area near Geneva. 

Lindsey 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Quartzite (Deep Lake Group) 

Early Proterozoic 

Wyoming (SE) 

Karlstrom, K. E., and Houston, R. S., 1979, Stratigraphy and 

uranium potential of Early Proterozoic metasedimentary rocks 

in the Medicine Bow Mountains, Wyoming: Wyoming Geol. 

Survey Rept. Inv. 13, p. 13-15, 42-43 

Quartzite with lenses of quartz pebbles 

White to light-gray 

410 m 

Trough cross-beds, ripple marks; fluvial deposits 

Conformably overlies Magnolia Formation; underlies Campbell 

Lake Formation with sharp to gradational contact (near type 

section), or overlies Cascade Quartzite 

Type section: NW1/4 sec. 2 and NE1/4 sec. 3, T. 16 N., 

R. 80 W., Medicine Bow Mountains, Carbon County, Wyo. Named 

for exposures W of Lindsey Lake, sec. 26, T. 17 N., R. 79 W. 

Link Spring Tuff Member (South Park Formation) 

1. Paleocene 

2. Colorado (C) 

3. Wyant, D. G., and Barker, Fred, 1976, Geologic map of the 

Milligan Lakes quadrangle, Park County, Colorado: U.S. 

Geol. Survey Geol. Quad. Map GQ-1343 

4. Tuff, with volcanic breccia, andesite flows, and minor 

porphyry-cobble conglomerate 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

5. Gray, brown, and pale-green 

6. Range <1-213 m 

1. Contains leaf impressions; forms ridges; tongue of thicker 

unnamed tuffaceous mudstone member S of Elkhorn quadrangle 

9. Overlies unnamed conglomeratic member; underlies unnamed 

arkosic member 

10. Type locality: Exposures N of Link Spring on Elkhorn Road, sec. 6, T. 10 s., R. 75 W., Elkhorn quadrangle, Park County, 

Colo. 

Linton Member (Fox Hills Formation) 

1. Late Cretaceous 

2. North Dakota (SC), South Dakota 

3. Klett, M. C., and Erickson, Mark, 1976, Type and reference 

sections for a new member of the Fox Hills Formation, Upper 

Cretaceous (Maestr.) in the Missouri Valley region, North 

and South Dakota: North Dakota Acad. Sci. Proc., v. 28, 

pt. 2' p. 3-24 

4. Siliceous arenite to subgraywacke sandstone with volcanic 

shards 

5. Olive-gray to grayish-brown 

6. 2.4 m, range 0.2-7 m 

1. Fine-grained, fossiliferous, estuarine channel deposit, 

forms butte caps 

9. Overlies unnamed facies of Fox Hills Formation; underlies 

Hell Creek Formation 

10. Type section: Section A216, composite section from NW tip 

to center of N side of butte, N1/2 sees. 8 and 9, T. 132 N., 

R. 76 W., 1.6 km E of Linton, Emmons County, N. Oak. 

Little Copper Formation (Copper Basin Group) 

1. Early Mississippian (Kinderhookian) 

2. Idaho (SC) 

3. Paull, R. A., and Gruber, D.P., 1977, Little Copper Formation--new name for lowest formation of Mississippian Copper 

Basin Group, Pioneer Mountains, south-central Idaho: Am. 

Assoc. Petroleum Geologists Bull., v. 61, no. 2, p. 256-262 

4. Argillite with interbedded quartzite, conglomerate, and 

limestone 

5. Dark-gray 

6. 1,120 m 

1. Thin- to medium-bedded, blocky weathering 

9. Base of formation not exposed and stratigraphic relation to 

underlying Milligen Formation not known; grades eastward 

into lower part of McGowan Creek Formation (Copper Basin 

Group); gradationally underlies Drummond Mine Limestone 

(Copper Basin Group) 

10. Type section: Basal part of Copper Basin Group type 

section, 150 m up N flank of ridge above Little Copper 

Creek, SW1/4NE1/4SE1/4 sec. 22, and continues N 45° E to 

center of NE1/4NW1/4 sec. 23, T. 4 N., R. 21 E., Pioneer 

Mountains, Blaine County, Idaho. Little Copper Creek is 

tributary of Copper Creek, which joins Muldoon Creek at 

Muldoon. 

Little Falls Formation (Mille Lacs Group) 

1. Precambrian, middle 

2. Minnesota (C) 

95 
96 

3. 

lf. 

5. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Morey, G. B., 1978, Lower and middle Precambrian stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol. Survey Rept. Inv. 21, p. 18-20 

Argillaceous slate, phyllite, and schist intercalated with 

quartz-rich metasiltstone and metagraywacke 

Gray 

Thin- to thick-bedded, abundant carbonate concretions 

Infolded with early Precambrian gneissic rocks; to N, passes 

into Mille Lacs Group, undivided, or may overlie Randall 

Formation (Mille Lacs Group) 

Type locality: Exposures on and near Mill Island in valley 

of Mississippi River near center of city of Little Falls, 

sec. 8 , T. lJ 1 N . , R. 32 W. , and sec. 19 , T. 129 N. , R. 32 W., Morrison County, Minn. 

Little Northeast Creek Member (James Run Formation) 

1. Paleozoic, early 

2. Maryland (NE) 

3. Higgins, M. W., 1977, Six new members of the James Run 

Formation, Cecil County, northeastern Maryland: U.S. Geol. 

Survey Bull. 1lf35-A, p. A123 

lf. Dacitic to rhyolitic granofels with relict phenocrysts of 

plagioclase and quartz 

5. Grayish-white to gray 

6. 1, 370 m 

7. Fine- to medium-grained, massive; at least four phases of 

folding; of metavolcanic to metasubvolcanic origin 

9. Grades into Frenchtown Member and biotite gneiss of sedimentary origin; probably partly equivalent to Principio· 

Furnace Member; underlies Gilpins Falls Member 

10. Type section: Section along Little Northeast Creek between 

outcrop belts of Gilpins Falls Member, on flanks of major 

anticline that trends NE from near Theodore, Cecil County, 

Md. 

Livengood Dome Chert 

1. Late Ordovician 

2. Alaska (NE) 

3. Chapman, R. M., and others, 1980, The Livengood Dome Chert, a new Ordovician formation in central Alaska, and its relevance to displacement on the Tintina fault: U.S. Geol. 

Survey Prof. Paper 1126-F, p. F1-F13 

lf. Chert with interbedded shale, argillite, and siltstone 

5. Light-gray to grayish-black; weathers gray, green, yellow, 

reddish brown, red 

6. Range 300-600 m 7. Thick- to thin-bedded, jointed, brecciated; complex structure with overturned folds and faults; shale fossiliferous 

(graptolites) 

9. Unconformably overlies Precambrian(?) or Cambrian rocks; 

underlies Middle Silurian to Early Devonian unnamed dolomite 

and limestone unit; Livengood Dome Chert and unnamed unit 

formerly were unnamed lower and upper units of Livengood 

Chert of Mertie (1937) (name abandoned) 

10. Type area: Exposures between valleys of Lost Creek and 

South Fork of Hess Creek, Livengood C-4 quadrangle, 

Alaska. Reference section in borrow pit 13.6 km W of town 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

of Livengood and 2.4 km W of Lost Creek, SW1/4 sec. 8, 

T. 8 N., R. 6 W. 

Loch Raven Schist (Wissahickon Group) 

1. Cambrian-Ordovician(?) 

2. Maryland (NC) 

3. Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the 

eastern Maryland Piedmont: Maryland Geol. Survey Rept. 

Inv. 27, p. 9-11, 23-24 

4. Biotite-plagioclase-muscovite-quartz schist with pods of 

vein quartz 

6. Range <1->600 m 

1. Medium- to coarse-grained 

8. Hydes Marble Member, Rush Brook Member 

9. Overlies Cockeysville Marble; underlies Oella Formation 

(Wissahickon Group) or Piney Run Formation (Wissahickon 

Group) 

10. Type locality: Outcrops on banks of Loch Raven Reservoir 

from Papermill Road (Ashland Avenue) S for 1.5 km, Baltimore 

County, Md. 

Lock Haven Formation 

1. Late Devonian 

2. Pennsylvania (C) 

3. Faill, R. T., and Wells, R. B., 1977, Bedrock geology and 

mineral resources of the Salladasburg and Cogan Station 

quadrangles, Lycoming County, Pennsylvania: Pennsylvania 

Geol. Survey, 4th ser., Atlas 133cd, p. 32-44 

4. Interbedded shale, siltstone, sandstone, minor conglomerate 

5. Gray 

6. 1,189 m 

1. Sandstone lenticular, cross-bedded; fossiliferous marine 

deposits 

9. Gradationally and conformably overlies Brallier Formation; 

conformably underlies Irish Valley Member (Catskill 

Formation) 

10. Type section: Exposure along Queens Run Road from borrow 

pit 1.5 km NW of Susquehanna River (West Branch) bridge at 

Lock Haven, 1.5 km NW to lower slopes of Simcox Mountain, N 

of junction of Queens Run Road and Swissdale Road, Lock 

Haven quadrangle, Clinton County, Pa. 

Lodoga Formation 

1. Early Cretaceous 

2. California (NW) 

3. Ingersoll, R. V. Rich, E. I., and Dickinson, W. R., 1977, 

Field guide--Great Valley Sequence, Sacramento Valley: 

Geol. Soc. America, Cordilleran Sec., Ann. Mtg., [Guidebook 

8J, p. 28, 31-32 

4. Siltstone, with many lenticular beds of sandstone and a few 

conglomerate lenses 

5. Dark-gray 

6. 4,200 m, range 3,600-4,800 m 1. Thin- to thick-bedded; mixed plutonic and volcanic detritus 

deposited in deep-marine trough 

8. Leesville Sandstone Member at base; informal Eckman Canyon 

sandstone member 

97 
98 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Conformably overlies Stony Creek Formation; conformably 

underlies Boxer Formation 

Type section: Along road between Lodoga and Sites, Lodoga 

quadrangle, Colusa County, Calif. 

Longford Member (Kiowa Formation) 

1. Early Cretaceous 

2. Kansas (NC) 

3. Franks, P. C., 1979, Paralic to fluvial record of an Early 

Cretaceous marine transgression--Longford Member, Kiowa 

Formation, north-central Kansas: Kansas Geol. Survey 

Bull. 219, 55 p. 

4. Clay rocks and siltstone with sparse layers of lignite and 

lenses of sandstone capped by distinctive siltstone unit 

5. Brown, light-gray, white 

6. 30 m, range <1-30 m 

1. Thin bedded to thin laminated; fluvial and estuarine 

deposits 

9. Unconformably overlies Wellington Formation; gradationally 

underlies upper unit of Kiowa Formation or disconformably 

underlies Dakota Formation 

10. Type section: Exposures N of town of Longford, from creek 

bottom to top of roadcut along road from Longford to Oak 

Hill, SW1/4 sec. 9, T. 10 S., R. 1 E., Clay County, Kans. 

Long Island Creek Gneiss 

1. Precambrian, late(?) and (or) Paleozoic, early(?) 

2. Georgia (NW) 

3. Higgins, M. W., and McConnell, K. I., 1978, The Sandy 

Springs Group and related rocks in the Georgia Piedmont--

nomenclature and stratigraphy: U.S. Geol. Survey 

Bull. 1457-A, p. A104 (Also published in: Georgia Geol. 

Survey Bull. 93, p. 53-54, 1978) 

4. Epidote-biotite-plagioclase gneiss 

5. Dark-gray, weathers yellow 

1. Weathers to massive saprolite 

9. In fault contact along SE boundary of Sandy Springs Group; 

in fault contact with all other adjacent rocks 

10. Type area: Exposures on SE side of Long Island Creek near 

and along Roswell Road, Sandy Springs quadrangle, Fulton 

County, Ga. 

Long Lake Till 

1. Holocene 

2. Wyoming (NC) 

3. Nelson, R. S., 1977, Glacial deposits of the Lake Angeline 

quadrangle, Bighorn Mountains, Wyoming: Earth Sci. Bull. v. 10, no. 1, p. 16 

4. Cobble and boulder till in quartz and feldspar matrix 

5. Reddish-brown, weathers light yellowish brown 

6. Range 15-38 m 

7. Loose; end and ground moraines 

9. Overlies Sherd Lake Till; underlies informal Lake Lame Deer 

till 

10. Type locality: Moraine enclosing Long Lake, center sec. 25, 

T. 15 N., R. 85 W., Bighorn Mountains, Johnson County, Wyo. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Long Pond Gneiss Meaber (Nashoba Formation) 

1. pre-Silurian 

2. Massachusetts (C) 

3. Bell, K. G., and Alvord, D. C., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 184-185, 208, app. 1 (in pocket) 

4. Sillimanitic biotite gneiss with lenticular bodies of 

amphibolite 

5. Medium-gray 

6. 1,160 m 

7. Medium-grained, stratified, relict sedimentary structures 

9. Overlies Fort Pond Member; underlies Beaver Brook Member 

10. Type locality: Belt 1,530'm wide extending from SW shore of 

Long Pond in town of Littleton, SW to S and W boundaries of 

Westford quadrangle, Middlesex County, Mass. 

Lookout 

1 • 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Mountain Conglomerate Member (Wasatch Formation) 

Eocene, early 

Wyoming (WC) 

Dorr, J. A., Jr., Spearing, D. R., and Steidtmann, J. R., 

1977, Deformation and deposition between a foreland uplift 

and an impinging thrust belt--Hoback Basin, Wyoming: Geol. 

Soc. America Spec. Paper 177, p. 23-24 

Conglomerate with sandstone and limestone clasts, sandstone 

interbeds 

Red, gray 

>660 m 

Large, angular to poorly rounded clasts in sandstone matrix; 

alluvial fan deposits 

Unconformably overlies Gannett Formation or other Mesozoic 

rocks; relation to Chappo Member (Wasatch Formation) and 

Pass Peak Formation to N and E not clear; lies at surface 

Type area: Exposures along South Fork Hoback River and on 

Lookout Mountain, T. 35 N., Rs. 114 and 115 W., Sublette 

County, Wyo. 

Lookout Mountain Ranch Drlf't 

1. Pleistocene 

2. Washington (C) 

3. Waitt, R. B., Jr., 1979, Late Cenozoic deposits, landforms, 

stratigraphy, and tectonism in Kittitas Valley, 

Washington: U.S. Geol. Survey Prof. Paper 1127, p. 12-13 

4. Till 

5. Dark-gray to black; produces reddish-brown soil 

6. >50 m 

7. Lateral moraines; conspicuously weathered 

9. Unconformably overlies Grand Ronde Basalt; younger than 

Thorp Gravel, older than Kittitas Drift. Unit includes 

S. C. Porter's (1976) informal till facies of Thorp Drift; 

Porter's Thorp Drift is here restricted to its outwash 

facies and renamed Thorp Gravel 

10. Type locality: Exposure at top of NW scarp of Lookout Mountain, SE1/4SW1/4 sec. 36, T. 20 N., R. 16 E., Cle Elum quadrangle, Kittitas County, Wash. Named for ranch that 

occupies top of Lookout Mountain. 

Lost Canyon Member (Ely Springs Dolostone) 

1. Late Ordovician 

99 
100 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Utah (NW), Nevada 

Budge, D. R., and Sheehan, P.M., 1980, The Upper Ordovician 

through Middle Silurian of the eastern Great Basin--Pt. 1, 

Introduction--historical perspective and stratigraphic 

synthesis; Pt. 2, Lithologic descriptions: Milwaukee Public 

Mus. Contr. Biology and Geology, no. 28, p. 15 (pt. 1); no. 29, p. 25-26 (pt. 2) 

Dolomite 

Light-gray and dark-gray interbedded 

67 m 

Thin- to thick-bedded, microcrystalline to finely crystalline laminated 

Overlies Barn Hills Member; underlies Floride Member 

Type section: Exposures N of Lost Canyon, NE1/4 sec. 30, 

T. 3 N., R. 17 W., Silver Island Mountains, Tooele County, 

Utah. 

Love Formation 

1. Pleistocene 

2. Texas (WC) 

3. Akersten, W. A., 1970, Red Light local fauna (Blancan) of 

the Love Formation, southeastern Hudspeth County, Texas: 

Texas Memorial Mus. Bull. 20, p. 4-8 

4. Silty clay and gravel interfingering with silt, sand, and 

clay 

5. Reddish-brown, orange-pink 

6. 36 m 

7. Lenticular, cross-bedded, basin and fluvial deposits; vertebrate fossils 

9. Conformably overlies Bramblett Formation; top eroded, capped 

by pediment gravel; in fault contact with Lower Cretaceous 

sedimentary rocks 

10. Type section: Section RL-1, along stream in TMM locality 

40664, on John D. Bramblett Ranch, Hudspeth County, Tex. 

Named for Love triangulation station, lat 30°48'27", 

long 105°12'12". 

Loves Park Member (Dunleith Formation) 

1. Middle Ordovician 

2. Illinois (NC) 

3. Willman, H. B., and Kolata, D. R., 1978, The Platteville and 

Galena Groups in northern Illinois: Illinois Geol. Survey 

Circ. 502, p. 50-51 

4. Dolomite, cherty dolomite, bentonite 

6. 15 m 

8. Calmar, Conover, Nasset, and Haldane Bentonite Beds 

9. Overlies Fairplay Member; underlies Wyota Member; equivalent 

of Mortimer, Rivoli, Sherwood, and Wall Members (Dunleith 

Formation) in area E and S of Freeport, Ill., where those 

members cannot be divided 

10. Type section: Harlem Southeast section, quarry 1.6 km SE of 

Harlem, center SE1/4 sec. 33, T. 45 N., R. 2 E., Winnebago 

County, Ill. Named for town of Loves Park, 1.6 km SW of 

type section. 

Lower Monuaental Member (Saddle Mountains Basalt) 

1. Miocene, late 

2. Washington (SE) 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

3. Swanson, D. A., and others, 1979, Revisions in stratigraphic 

nomenclature of the Columbia River Basalt Group: U.S. Geol. 

Survey Bull. 1457-G, p. G53-G54 

4. Basalt 

6. 30 m, range 25-60 m 7. Nearly aphyric, one flow 

9. Overlies river gravel in an ancestral Snake River canyon 

whose lower end appears to be eroded into Ice Harbor Member; 

believed to be youngest basalt of Columbia River Basalt 

Group and its Yakima Basalt Subgroup 

10. Type locality: Prominent roadcut 1 km S of Lower Monumental 

Dam, NW1/4SE1/4 sec. 3, T. 12 N., R. 34 E., Lower Monumental 

Dam quadrangle, Walla Walla County, Wash. 

Lyman Member (Ammonoosuc Formation) 

1. Middle Ordovician 

2. New Hampshire (WC) 

3. Prager, G. D., 1980, Stratigraphy of the Gardner Mountain 

area, New Hampshire: Northeastern Geology, v. 2, no. 1, 

p. 34 

4. Mafic chlorite schist 

5. Dark-green 

7. Slaty, well-developed cleavage 

9. Overlies West Bath Member (Ammonoosuc Formation); underlies 

Partridge Formation 

10. Type locality: In road along E side of Gardner Mountain, 

2.2 km WNW of Lyman village, Grayton County, N.H. 

Lynnhaven 

1 • 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Member (Tabb Formation) 

Pleistocene, late 

Virginia (SE) 

Johnson, G. H., 1976, Geology of the Mulberry Island, 

Newport News North, and Hampton quadrangles, Virginia: 

Virginia Div. Mineral Resources Rept. Inv. 41, p. 35-37 

Gravelly and clayey sand 

Bluish-gray, reddish-brown 

1.77 m, range <1-2m 

Beach and nearshore marine deposits 

Unconformably overlies Sedgefield Member (Tabb Formation), 

Norfolk Formation, or Yorktown Formation; unconformably 

underlies Poquoson Member (Tabb Formation) 

Type section: Exposure along Butler Farm ditch, 1.08 km W 

of intersection of Magruder Boulevard (State Highway A134) 

and Butler Farm Road, city of Hampton, Va. Named for subdivision of Lynnhaven, city of Hampton. 

Mableton Amphibolite Member (Powers Ferry Formation) 

1. Precambrian, late(?) and (or) Paleozoic, early(?) 

2. Georgia (NW) 

3. Higgins, M. W., and McConnell, K. I., 1978, The Sandy 

Springs Group and related rocks in the Georgia Piedmont--

nomenclature and stratigraphy: U.S. Geol. Survey 

Bull. 1457-A, p. A102-A103 (Also published in: Georgia 

Geol. Survey Bull. 93, p. 52, 1978) 

4. Hornblende-plagioclase amphibolite 

6. Range 500-700 m 7. Layered 

9. Within Powers Ferry Formation 

101 
102 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Type area: Exposures along and N of Fountain Road NE of 

Mableton, Mableton quadrangle, Cobb County, Ga. 

Madawaska 

1 • 

Lake Formation 

Ordovician and Early Silurian(?) (Caradocian to Llandoverian(?)) 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Maine (NE), Canada (New Brunswick) 

Roy, D. C., and Mencher, Ely, 1976, Ordovician and Silurian 

stratigraphy of northeastern Aroostook County, Maine: Geol. 

Soc. America Mem. 148, p. 29-31, 47-48 

Slate interbedded with siltstone and graywacke 

Green-gray, gray, weathers orange 

>600 m 

Fine-grained, brittle, thin-bedded 

Oldest rocks exposed in cores of anticlines; interfingers 

with Winterville Formation; underlies Aroostook River Formation or unconformably underlies Frenchville Formation 

Type area: Exposures along N shore of Madawaska Lake, along 

Maine Route 161, 3.7 km N of Little Madawaska River, 

Aroostook County, Maine. 

Magnolia Formation (Deep Lake Group) 

1. Early Proterozoic 

2. Wyoming (SE) 

3. Karlstrom, K. E., and Houston, R. S., 1979, Stratigraphy and 

uranium potential of Early Proterozoic metasedimentary rocks 

in the Medicine Bow Mountains, Wyoming: Wyoming Geol. 

Survey Rept. Inv. 13, p. 11-13, 40-42 

4. Arkosic conglomerate, quartzite 

6. Conglomerate: 150 m; quartzite: 425 m 

7. Conglomerate, poorly sorted, radioactive; quartzite, coarse- grained; fluvial deposits 

8. Informal lower radioactive conglomerate member and upper 

quartzite member 

9. Unconformably overlies Phantom Lake Suite; conformably 

underlies Lindsey Quartzite (Deep Lake Group) 

10. Type section: Radioactive conglomerate: center sec. 10, 

T. 16 N., R. 80 W.; quartzite: E of Stamp Mill Lake, sec. 16, T. 16 N., R. 80 W., Medicine Bow Mountains, Carbon 

County, Wyo. Derivation of name not stated. 

Maiden Creek Member (Allentown Formation) 

1. Late Cambrian 

2. Pennsylvania (SE) 

3. MacLachlan, D. B., 1979, Geology and mineral resources of 

the Temple and Fleetwood quadrangles, Berks County, 

Pennsylvania: Pennsylvania Geol. Survey, 4th ser., Atlas 

187ab, p. 18-20 

4. Magnesian limestone, dolomite, chert 

5. Dark- to medium-gray 

6. 375 m 

7. Distinctive dark brownish chert fragments 

9. Conformably overlies Muhlenberg Member (Allentown 

Formation); conformably underlies Stonehenge Formation 

(Beekmantown Group) 

10. Type section: Exposures along Maiden Creek from Ontelaunee 

Reservoir to Schuylkill River, Berks County, Pa. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Maidens Gneiss 

1. Precambrian, late, and (or) Early Cambrian 

2. Virginia (EC) 

3. Poland, F. B., Glover, Lynn, III, and Mose, D. G., 1979, The 

geology of the rocks along the James River between Sabot and 

Cedar Point, Virginia, in Glover, Lynn, III, and Tucker, R. 

D., eds., Virginia Piedmont geology along the James River 

from Richmond to the Blue Ridge--Field trip 1, of Guides to 

field trips 1-3: Blacksburg, Va., Geol. Soc. America, 

Southeastern Sec., p. 11-13 

4. Biotite gneiss, schist, quartzite 

7. NNE-trending folds and W-facing overturned folds 

9. Structurally overlies Sabot Amphibolite 

10. Type area: Exposures along James River between State Farm 

and Cedar Point, Goochland County, Va. Named for village of 

Maidens. 

Makah Formation (Twin River Group) 

1. Eocene, late, to Oligocene (Narizian to Zemorrian) 

2. Washington (NW) 

3. Snavely, P. D., Jr., Niem, A. R., and Pearl, J. E., 1978, 

Twin River Group (upper Eocene to lower Miocene)--defined to 

include the Hoko River, Makah, and Pysht Formations, Clallam 

County, Washington: U.S. Geol. Survey Bull. 1457-A, 

p. A116-A117 

4. Siltstone, sandstone, conglomerate, tuff, with calcareous 

concretions 

6. >2,800 m 7. Thin- to thick-bedded, rhythmically bedded, deep-marginalbasin sequence, including turbidite sandstone packets and an olistostrome 

8. [Six formal members of Snavely and others (1980): Baada 

Point, Dtokoah Point, Carpenters Creek Tuff, Klachopis 

Point, Third Beach, and Jansen Creek Members] 

9. Gradationally or locally unconformably overlies Hoko River 

Formation; gradationally or locally unconformably underlies 

Pysht Formation 

10. Type section: Shore cliffs and wave-cut platform exposures 

along Strait of Juan de Fuca from Waadah Island and Baada 

Point to Kydaka Point, Clallam County, Wash. Named for 

Makah Indian Reservation, NW Olympic Peninsula. 

Malibu Bowl Tongue (Conejo Volcanics) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E23 

4. Andesitic and basaltic flows and flow breccias 

6. 143 m 

9. Upper of three named tongues of Conejo Volcanics (Topanga 

Group), which are recognized only in upper plate of Malibu 

detachment fault. Overlies Dry Canyon Sandstone Member 

(Calabasas Formation) or Solstice Canyon Tongue (Conejo 

Volcanics); underlies and intertongues with Newell Sandstone 

Member (Calabasas Formation) 

10. Type area: Malibu Bowl [populated place in SW1/4 sec. 23, 

103 
104 LEXICON OF GEOLOGIC NAMES OP THE UNITED STATES 

T. 1 S., R. 18 W.J, Santa Monica Mountains, WC Malibu Beach 

quadrangle, Los Angeles County, Calif. 

Mallard Island Member (Oahe Formation) 

1. Pleistocene (Wisconsinan) 

2. North Dakota (C) 

3. Clayton, Lee, Moran, S. R., and Bickley, W. B., Jr., 1976, 

Stratigraphy, origin, and climatic implications of late 

Quaternary upland silt in North Dakota: North Dakota Geol. 

Survey Misc. Ser., no. 54, p. 3 

4. Silt loam, sand, and clay 

5. Light-brown 

6. 1 m 

9. Overlies thin layer of lag pebbles eroded from underlying 

glacial sediments; underlies Aggie Brown Member (Oahe 

Formation) 

10. Type section: Riverdale Section, bluffs of Lake Sakakawea, 

center sec. 22, T. 147 N., R. 84 W., 4 km N of Riverdale, 

McLean County, N. Dak. Named for Mallard Island in Lake 

Sakakawea. 

Marcella 

1 • 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

Formation 

Late Mississippian 

Arkansas (NC) 

Ogren, D. E., 1968, Stratigraphy of Upper Mississippian 

rocks of northern Arkansas: Am. Assoc. Petroleum Geologists 

Bull., v. 52, no. 2, p. 282-294 

Calcarenite, limestone breccia, shale 

Black, dark-gray 

71 m Thick-bedded, massive, fossiliferous 

Wallace Creek Shale Member at base 

Conformably overlies Pitkin Limestone; conformably and transitionally underlies Cane Hill Member (Hale Formation) 

Type section: Exposure along intermittent tributary of 

Wallace Creek, NW1/4 sec. 12, T. 13 N., R. 9 W., near Marcella, Stone County, Ark. 

Marco Junction Formation (Big Cypress Group) 

1. Early Cretaceous (Comanchean) 

2. Florida (SE) 

3. Winston, G. D., 1976, Six proposed formations in the 

undefined portion of the Lower Cretaceous section in south 

Florida: Gulf Coast Assoc. Geol. Socs. Trans., v. 26, p. 71 

4. Chalky limestone with dolomite and anhydrite beds 

6. 101 m 

7. Dense limestone at base; thick, persistent anhydrite at top 

9. Overlies Rattlesnake Hammock Formation (Ocean Reef Group); 

underlies Gordon Pass Formation (Big Cypress Group) 

10. Type section: Humble No. 1 Collier Corp. well, depthinterval 3268-3369 m, sec. 27, T. 50S., R. 26 E., Collier 

County, Fla. Named for Marco Junction, road junction 8 km S 

of type well. 

Marshall Butte Member (Sheep Crossing Formation) 

1. Miocene, middle and late 

2. Arizona (EC) 

3. Merrill, R. K., and Pewe, T. L., 1977, Late Cenozoic geology 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

of the White Mountains, Arizona: Arizona Bur. Geology and 

Mineral Technology Spec. Paper 1, p. 18-19 

4. Interbedded laharic breccia, sandstone, airfall tephra, 

diamicton mudflows 

6. 65 m 7. Debris flows deposited in colluv.ial fans; alasts throughout, 

including quartz latite boulders, are from lavas of Mount 

Baldy Volcano 

9. Overlies Mount Baldy Formation; underlies Campground Member 

(Sheep Crossing Formation) 

10. Type section: Lat 33°48"30" N., long 109°46"30" W., Corn 

Creek Plateau quadrangle, ~pache County, Ariz. Named for 

Marshall Butte, hill on SW side of Mount Baldy, Marshall 

Butte quadrangle. 

Marty Dolomite Bed (Flowerpot Shale) 

1. Permian 

2. Oklahoma (SC) 

3. Johnson, K. S., 1976, Permian Copper Shales of southwestern 

Oklahoma, in Stratiform copper deposits of the midcontinent 

region, a symposium: Oklahoma Geol. Survey Circ. 77, p. 3-14 

4. Dolomite 

5. Light-gray, yellowish, tan 

6. 0.15 m, range 0.03-0.15 m 

7. Microgranular, platy, caps low escarpment, marker bed above 

copper shales 

9. 7-8 m below top of Flowerpot Shale. Formerly considered 

equivalent to Kiser Gypsum Bed and referred to as Kiser Bed 

in Creta area 10. Type locality: W1/2 sec. 3, T. 1 S., R. 22 W., Jackson 

County, Okla. Named for exposures near Marty siding on 

railroad E of Creta. 

McCully Formation 

1. Middle Pennsylvanian (Morrowan) 

2. Oklahoma (EC) 

3. Sutherland, P. K., and Henry, T. W., 1977, Carbonate 

platform facies and new stratigraphic nomenclature of the 

Morrowan Series (Lower and Middle Pennsylvanian), northeastern Oklahoma: Geol. Soc. America Bull., v. 88, no. 3, 

p. 432-435 

4. Shale, limestone 

6. 19.5 m, range 17.7-22.9 m 8. Chisum Quarry Member, informal shale "A" member, Greenleaf 

Lake Limestone Member, informal shale "B" member 

9. Unconformably overlies Sausbee Formation; unconformably 

underlies Atoka Formation 

10. Type section: Measured Section 1, W bluff of Arkansas 

River, 9-183 m S from W end of Webbers Falls Lock and Dam, 

SW1/4SW1/4SE1/4 sec. 34, T. 13 N., R. 20 E., and Measured 

Section 3, 0.5 km NW of MS 1 along river bluff, 

S1/2NW1/4SW1/4 sec. 34, T. 13 N., R. 20 E., Muskogee County, 

Okla. Probably named for exposures on McCully Mountain, 

bluff on W side of Arkansas River N of Webber Falls Lock and 

Dam. 

McKay Bay Member (Bush Bay Dolostone) 

1. Middle Silurian (Niagaran) 

105 
106 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Michigan (EC) 

Johnson, A. M., and others, 1979, The Maple Block knoll reef 

in the Bush Bay Dolostone (Silurian, Engadine Group), 

Northern Peninsula of Michigan: Michigan Univ. Mus. Paleontology Papers on Paleontology, no. 20, p. 18 

Dolostone 

Gray, mottled 

20 m 

Massive, vugular, medium- to coarsely crystalline, organic 

reef, fossil-rich reefal and fossil-poor interreefal facies 

Overlies Swede Road Member; uppermost unit of Bush Bay 

Dolostone (Engadine Group), lies at surface or unconformably(?) underlies Pointe aux Chenes Formation (Salina Group) 

Type section: Near McKay Bay along Michigan Route 134, 5 km 

E of Cedarville, sec. 33, T. 42 N., R. 1 E., Mackinac 

County, Mich. 

Mesa Peak Breccia Member (Calabasas Formation) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

4. 

6. 

7. 

9. 

10. 

Mesilla 

1 • 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

p. E23 

Breccia 

288 m 

Angular fragments of volcanic rock in very coarse grained 

sandstone 

Conformably overlies Newell Sandstone Member (Calabasas 

Formation); upper contact not exposed [or may unconformably 

underlie Modelo Formation]; in fault contact with Sespe and 

Topanga Canyon Formations 

Type locality: Mesa Peak, sec. 24, T. 1 S., R. 18 W., Santa 

Monica Mountains, WC Malibu Beach quadrangle, Los Angeles 

County, Calif. 

Valley Shale 

Early Cretaceous 

New Mexico (SC), Texas, Mexico 

Strain, W. S., 1976, New formation names in the Cretaceous 

at Cerro de Cristo Rey, Dofta Ana County, New Mexico, 

Appendix 2, in Lovejoy, E. M.P., Geology of Cerro de Cristo 

Rey uplift, Chihuahua and New Mexico: New Mexico Bur. Mines 

and Mineral Resources Mem. 31, p. 80-81 

Clay shale with limestone and siltstone beds 

Olive-gray 

64 m 

Thin-bedded, fossiliferous 

Conformably overlies Muleros Formation; conformably underlies Anapra Sandstone 

Type section: N side of largest railroad cut in which Ebound traffic passes, NW1/4NW1/4NE1/4 sec. 16, T. 29 S., 

R. 4 E., Smeltertown quadrangle, Dofta Ana County, N.Mex. 

Named for Mesilla Valley, on R1o Grande flood plain N of 

Cerro de Cristo Rey, Dofta Ana County. 

Metallic City Tuff 

1. Oligocene, late 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

2. 

3. 

Nevada (WC) 

Speed, R. C., and Cogbill, A. H., 

of the Candelaria region, Nevada: 

part 2, v. 90, no. 2, p. 456-493 

Ash-flow tuff 

70 m 

1979, Cenozoic volcanism 

Geol. Soc. America Bull., 

4. 

6. 

7. 

9. 

Basal zone moderately compacted, grading up to vitrophyre, 

strongly compacted upper zone vitric and stony 

Unconformably overlies tuff unit 4; unconformably underlies 

tuff unit 6 

10. Type locality: Cliff 2.5 km S. 64° W. of Metallic City 

site, Candelaria Hills, Mineral County, Nev. 

Mickey Pass Tuff 

1. Oligocene 

2. Nevada (WC) 

3. Proffett, J. M., Jr., and Proffett, B. H., 1976, Stratigraphy of the Tertiary ash-flow tuffs in the Yerington 

district, Nevada: Nevada Bur. Mines and Geology Rept. 27, 

p. 8-19 

4. Ash-flow tuffs with minor interbedded rhyolitic tuffs and 

sedimentary rocks 

5. Brown, pink, lavender 

6. 760 m, range 760->900 m 7. Two major ash-flow tuff cooling units with interbedded thin 

tuffs and sediments 

8. Guild Mine Member, Weed Heights Member, and unnamed map 

units 4, 5, 7 

9. Unconformably overlies unnamed early Tertiary rocks; underlies Singatse Tuff 

10. Type area: Exposures NE of Mickey Pass, SE1/4 sec. 13, 

T. 13 N., R. 24 E., and SW1/4 sec. 18, T. 13 N., R. 25 E., 

Singatse Range, Lyon County, Nev. 

Middlesex Fells Volcanic Complex 

1. Precambrian(?) 

2. Massachusetts (C) 

3. Bell, K. G., and Alvord, D. C., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 188-189, 199-201, app. 1 (in pocket) 

4. Mafic flow rocks, pyroclastic deposits, and tuffs, all metamorphosed to amphibolite facies; minor quartzite and gneiss 

5. Dark-gray to black 

6. 15,000 m 

7. Fine-grained; thinly laminated lentils; pillow structures; 

ripple-bedding 

9. Conformably overlies Westboro Formation; intruded by Dedham 

Granodiorite; unconformably underlies Greenleaf Mountain and 

Burlington Formation 

10. Type locality: NW Middlesex Fells Reservation and NE into 

Wakefield, including High Rock hill, Boston North 

quadrangle, Middlesex County, Mass. 

Millbrig Bentonite Bed (Glencoe Member of Spechts Ferry Formation) 

1. Middle Ordovician 

2. Illinois (NW), Wisconsin 

3. Willman, H. B., and Kalata, D. R., 1978, The Platteville and 

Galena Groups in northern Illinois: Illinois Geol. Survey 

107 
108 

4. 

5. 

6. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Circ. 502, p. 43-44 

Bentonite clay 

Light-gray, stained orange 

0.10 m 

At or near base of Glencoe Member, which overlies Castlewood 

Member (Spechts Ferry Formation) 

Type section: Millbrig Southeast section, along E bank of 

Galena River, 1.6 km SE of Millbrig, center sec. 34, 

T. 29 N., R. 1 E., Jo Daviess County, Ill. 

Mille Lacs Group 

1. Precambrian, middle 

2. Minnesota {C) 

3. Morey, G. B., 1978, Lower and middle Precambrian stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol. Survey Rept. Inv. 21, p. 15-24 

4. Metasedimentary arenitic quartz-rich rocks, metagraywacke, 

argillaceous, slate, dolomite, and metavolcanic rocks 

6. 1,000 m 

8. Denham, Little Falls, Glen Township, and Randall Formations, 

and informal Trout Lake unit 

9. Unconformably overlies McGrath Gneiss or early Precambrian 

gneissic rocks, undivided; unconformably underlies Animikie 

Group 

10. Type area: Named for Mille Lacs Lake, Mille Lacs and Aitkin 

Counties, Minn. Type localities of its formations are in 

Pine, Aitkin, Morrison, and Crow Wing Counties. 

Mina Formation 

1. Permian 

2. Nevada (WC) 

3. Speed, R. C., 1977, Excelsior Formation, west-central 

Nevada--stratigraphic appraisal, new divisions, and paleogeographic interpretations, in Stewart, J. H., and others, 

eds., Paleozoic paleogeography of the western United States--

Pacific Coast Paleogeography Symposium [Bakersfield, Calif., 

1977]: Los Angeles, Soc. Econ. Paleontologists and Mineralogists, Pacific Sec., p. 328-332 

4. Dominantly volcanogenic turbidite, lesser chert, pelite, and 

quartz sandstone 

6. >1,000 m 

1. Turbidite sequences fining upward; extensively thrustfaulted, forming nappes 

9. Base not exposed; unconformably (angular) underlies Gold 

Range Formation 

10. Type area: Lower Douglas Canyon, sec. 23, T. 6 N., 

R. 34 E., Garfield Hills, 3-5 km SW of town of Mina, Mineral 

County, Nev. 

Mixer Pond Member (Passagassawakeag Formation) 

1. Precambrian 

2. Maine (SC) 

3. Bickel, C. E., 1976, Stratigraphy of the Belfast quadrangle, 

Maine: Geol. Soc. America Mem. 148, p. 103-104 

4. Feldspathic gneiss composed of hornblende, biotite, ferrosalite, and magnetite 

5. Light-gray, white 

6. 300 m 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

7. Fine-grained, massive, compositionally layered 

9. Unconformably underlies Hogback Schist 

10. Type locality: Near Mixer Pond, Belfast quadrangle, Waldo 

County, Maine. 

Mobile Clay 

1. Miocene, middle 

2. Alabama (SW) 

3. Isphording, W. C., 1977, Petrology and stratigraphy of the 

Alabama Miocene: Gulf Coast Assoc. Geol. Socs. Trans., 

v. 27, p. 305-306 

4. Clay 

5. Dark-green, lavender, gray, brassy-yellow 

6. <450 m 

7. Laminated to massive, marine and transitional-marine 

deposit, fossiliferous 

9. Overlies Chickasawhay Limestone or (downdip to S) Tampa 

Limestone; underlies Ecor Rouge Sand 

10. Type area: Along Mobile River, highways, and in gravel pits 

in Mobile County, Ala. 

Moffett Creek Formation 

1. Silurian or older 

2. California (NW) 

3. Hotz, P. E., 1977, Geology of the Yreka quadrangle, Siskiyou 

County, California: U.S. Geol. Survey Bull. 1436, p. 25-30 

4. Sandstone or siltstone blocks in matrix of shale 

5. Medium-gray to dark-greenish-gray 

7. Strongly sheared; olistostrome or broken formation 

9. In thrust contact with underlying Duzel Phyllite and 

Schulmeyer Gulch sequence, and with overlying Sissel Gulch 

Graywacke 

10. Type locality: Moffett Creek, sec. 12, T. 43 N., R. 8 W., 

Siskiyou County, Calif. 

Moore Hollow Group 

1. Middle Cambrian to Early Ordovician 

2. Texas (C) 

3. Barnes, V. E., and Bell, W. C., 1977, The Moore Hollow Group 

of central Texas: Texas Bur. Econ. Geology Rept. Inv. 88, 

169 p. 

4. Limestone, dolomite, sandstone, quartz sand, glauconite 

5. Gray 

6. Range 180-540 m 7. Granular limestone, fine-grained dolomite, fossiliferous 

8. Riley Formation and its Hickory Sandstone, Cap Mountain 

Limestone, and Lion Mountain Sandstone Members; and Wilberns 

Formation and its Welge Sandstone, Morgan Creek Limestone, 

Point Peak, and San Saba Members 

9. Unconformably overlies Precambrian rocks; conformably underlies Tanyard Formation (Ellenburger Group) 

10. Type locality: East Canyon, just S of Moore Hollow, SE 

Riley Mountains, Llano County, Tex. 

Moore Bouse Member (Yorktown Formation) 

1. Pliocene, early 

2. Virginia (SE) 

3. Ward, L. W., and Blackwelder, B. W., 1980, Stratigraphic 

109 
110 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

revision of upper Miocene and lower Pliocene beds of the 

Chesapeake Group, middle Atlantic Coastal Plain: U.S. Geol. 

Survey Bull. 1482-D, p. D43-D48 

Clayey sand, shell hash 

Tan, orange 

4 m, range 4-6 m 

Locally cemented, cross-bedded 

Conformably overlies Morgarts Beach Member; upper contact 

not exposed, or underlies upper Pliocene or Pleistocene 

deposits 

Type section: Bluffs at Moore House, S bank of York River, 

Yorktown Battlefield Park, York County, Va. 

Moose Channel Formation 

1. Late Cretaceous and Paleocene 

2. Canada (District of Mackenzie), Alaska 

3. Mountjoy, E. W., 1967, Upper Cretaceous and Tertiary 

stratigraphy, northern Yukon Territory and northwestern 

District of Mackenzie: Canada Geol. Survey Paper 66-16, 

p. 8-9. Geographically extended to Alaska in: Lyle, W. M., 

and others, 1980, Post-Early Triassic formations of northeastern Alaska and their petroleum reservoir and source-rock 

potential: Alaska Div. Geol. and Geophys. Surveys Geol. 

Rept. 76, p. 6 

4. Feldspathic, laminated sandstone interbedded with silty 

shale and conglomerate lenses 

5. Greenish-gray to brown 

6. 365 m 

7. Nonmarine, contains plant fragments and coal seams, loosely 

consolidated 

9. Overlies Upper Cretaceous shale; unconformably underlies 

Pleistocene and Holocene deposits 

10. Type locality: Exposures along Fish River, on W side of 

Mackenzie Delta, Canada. Named for Moose Channel, 

Morgarts 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

lat 68°43' N., long 136°23' W. 

Beach Member (Yorktown Formation) 

Pliocene, early 

Virginia (SE), North Carolina 

Ward, L. W., and Blackwelder, B. W., 1980, Stratigraphic 

revision of upper Miocene and lower Pliocene beds of the 

Chesapeake Group, middle Atlantic Coastal Plain: U.S. Geol. 

Survey Bull. 1482-D, p. D40-D43 

Sandy to silty clay 

Gray 

3 m, range 3-6 m 

Fine--grained, fossiliferous 

Conformably overlies Rushmere Member; conformably underlies 

Moore House Member 

Type section: Exposures 1 km below Morgarts Beach, R. bank 

of James River, Isle of Wight County, Va. Named for beds at 

Morgarts Beach. 

Moultrie Member (Santee Limestone) 

1. Eocene, middle (Claibornian) 

2. South Carolina (C) 

3. Ward, L. W., and others, 1979, Stratigraphic revision of 

Eocene, Oligocene, and lower Miocene formations of South 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Carolina: South Carolina Geol. Survey Geol. Notes, v. 23, 

no. 1, p. 5-9 

4. Calcirudite and biosparrite 

5. Light-gray 

6. 6 m 

7. Fossiliferous (bryozoan biosparrite, bivalv~_molds), 

indurated; phosphate-coated, burrowed upper surface 

9. Overlies Black Mingo Formation [subsurface]; unconformably 

underlies Cross Member (Santee Limestone) 

10. Type section: Section at Martin Marietta Co. Berkeley 

quarry, 2.4 km S of Route 6 and Route 59 intersection, 

Chicora 15' quadrangle, BerKeley County, S.C. Named for 

nearby Lake Moultrie. 

Mount Baldy Formation 

1. Miocene 

2. Arizona (EC) 

·3. Merrill, R. K., and Pewe, T. L., 1977, Late Cenozoic geology 

of the White Mountains, Arizona: Arizona Bur. Geology and 

Mineral Technology Spec. Paper 1, p. 9-17 

4. Latite, quartz latite, alkali trachyte, and rhyolite flows 

5. Light-gray, grayish-red to bluish-gray 

6. <500 m 7. Lava flows erupted from Mount Baldy Volcano; platy or blocky 

jointing 

8. Informal lower and upper members 

9. Overlies early volcanic and volcaniclastic rocks of middle 

Tertiary age; underlies Sheep Crossing Formation or lies at 

surface 

10. Type locality: Along ridge between East Fork of Little 

Colorado River and West Fork of Black River, Apache County, 

Ariz. Named for Mount Baldy, which includes Baldy Peak, 

highest peak of White Mountain Massif. 

MOunt Baldy Rhyolite Member (Mount Belknap Volcanics) 

1. Miocene 

2. Utah (SC) 

3. Steven, T. A., and others, 1979, Revised stratigraphy and 

radiometric ages of volcanic rocks and mineral deposits in 

the Marysvale area, west-central Utah: U.S. Geol. Survey 

Bull. 1469, p. 29 

4. Rhyolite 

5. Light-gray to white 

6. 300 m 7. Fine-grained, locally prominent, contorted lava flows 

9. Overlies Blue Lake Rhyolite Member or unnamed middle tuff or 

sedimentary breccia members; units are part of intracaldera 

facies of Mount Belknap Volcanics 

10. Type area: Exposures on cliffs forming upper slopes of 

Mount Baldy, Piute County, Utah. 

Mount Blue Member (Seboomook Formation) 

1. Early Devonian 

2. Maine (WC) 

3. Pankiwskyj, K. A., 1979, Bedrock geology of the Kingfield 

and Anson 15' quadrangles, Franklin and Somerset Counties, 

Maine: Maine Geol. Survey Geol. Map Series GM-7, 51 p. 

4. Metasiltstone and metapelite 

111 
112 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Gray 

1,000 m Rhythmically bedded, rusty-weathering 

Overlies Hildreth Formation; gradationally underlies Temple 

Stream Member (Seboomook Formation) 

Type locality: Summit of Mount Blue, N Dixfield quadrangle, 

Franklin County, Maine. 

Mount Emily Dacite 

1. Oligocene, middle 

2. Oregon (SW) 

3. Beaulieu, J. D., and Hughes, P. W., 1976, Land use geology 

of western Curry County, Oregon: Oregon Dept. Geology and 

Mineral Industries Bull. 90, p. 20-21, 52 

4. Dacite, diorite, syenite 

5. Light-colored 

7. Two large intrusive bodies form prominent mountain with 

radiating dike ridges 

9. Intrusive into Dothan Formation 

10. Type area: Mount Emily, Mount Emily quadrangle, Curry 

County, Oreg. 

Mount Galen Volcanics 

1. Eocene, late, and Oligocene, early 

2. Alaska (C) 

3. Decker, J. E., and Gilbert, W. G., 1978, The Mount Galen 

Volcanics--a new middle Tertiary volcanic formation in the 

central Alaska Range: Alaska Geol. and Geophys. Surveys 

Geol. Rept. 59, p. 1-11 

4. Andesitic and basaltic breccia, lava flows, tuff 

6. >1,000 m 

9. Unconformably overlies Cantwell Formation; as possible 

eruptive center, cuts Triassic(?) metabasalt; conformably 

underlies Tertiary lignite-bearing sedimentary rocks 

10. Type locality: Narrow ridge extending from Stony Creek SW 

to top of Mount Galen in Mount McKinley B-1 quadrangle, 

Mount McKinley National Park, WC Alaska Range, Alaska. 

MOunt Laird Turf 

1. Eocene, late 

2. Utah (WC) 

3. Lindsey, D. A., 1979, Geologic map and cross-sections of 

Tertiary rocks in the Thomas Range and northern Drum 

Mountains, Juab County, Utah: U.S. Geol. Survey Misc. Inv. 

Ser. Map I-1176 

4. Rhyodacite to quartz latite ash-flow tuff, with crystals of 

plagioclase, biotite, horneblende, and pyroxene 

5. Pink 

6. 80 m, range 80-500 m 

9. Overlies Drum Mountains Rhyodacite; unconformably underlies 

Joy Tuff 

10. Type locality: Exposures near Mount Laird in Drum Mountains, sees. 23 and 26, T. 14 S., R. 11 W., Juab County, 

Utah. 

Mount Reba Conglomerate 

1. Pliocene 

2. California (C) 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

3. Axelrod, D. I., 1980, Contributions to the Neogene paleobotany of central California: California Univ. Pubs. Geol. 

Sci. , v. 121 , p • 25 

4. Boulder conglomerate 

6. 24 m 

7. Poorly lithified 

9. Unconformably overlies Disaster Peak Formation or Relief 

Peak Formation; youngest Tertiary unit in area 10. Type locality: Ridge E of Mount Reba, Alpine County, Calif. 

Mount Sheridan Gabbro (Roosevelt Gabbros) 

1. Cambrian 

2. Oklahoma (C) 

3. Powell, B. N., Gilbert, M. C., and Fischer, J. F., 1980, 

Lithostratigraphic classification of basement rocks of the 

Wichita province, Oklahoma: Summary: Geol. Soc. America 

Bull., pt. 1, v. 91, no. 9, p. 510-513 

4. Biotite gabbro grading upward into ferrogranodiorite 

5. Dark-gray, weathers reddish brown 

6. >200 m 

7. Medium-grained, hypidiomorphic, sill-like intrusive body 

9. Intrusive into Glen Mountains Layered Complex (Raggedy 

Mountain Gabbro Group); intruded by Mount Scott Granite 

10. Type locality: N and E slopes of Mount Sheridan, NE1/4 and 

SE1/4 sec. 5, T. 3 N., R. 13 W., Wichita Mountains, Comanche 

County, Okla. 

Mount Washington Amphibolite (Baltimore Mafic Complex) 

1 . Cambrian(?) 

2. Maryland (NC) 

3. Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the 

eastern Maryland Piedmont: Maryland Geol. Survey Rept. 

Inv. 27, p. 14, 28-30 

4. Plagioclase, amphibole 

5. Dark-green to black 

7. Fine- to medium-grained, massive 

9. In thrust-fault contact with Loch Raven Schist, Oella and 

Sykesville Formations (Wissahickon Group); overlies 

Hollofield Layered Ultramafite (Baltimore Mafic Complex) in 

E-W anticline which is truncated on SE by James Run 

Formation 

10. Type locality: Outcrops along unnamed S-flowing tributary 

of Western Run near intersection where Cross Country 

Boulevard becomes Kelly Avenue, Mount Washington section of 

Baltimore City, Baltimore County, Md. 

Mud Springs Canyon Formation 

1. Late Triassic and Early Jurassic(?) 

2. Nevada (WC) 

3. Speed, R. C., 1976, Geologic map of the Humboldt lopolith 

and surrounding terrane, Nevada: Geol. Soc. America Map and 

Chart Ser. MC-14, p. 2 

4. Limestone, dolomite, minor quartz sandstone 

6. 600 m 

7. Massive- to medium-bedded, fossiliferous 

9. Conformably overlies Hoyt Canyon Formation; unconformably 

underlies Boyer Ranch Formation 

113 
114 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Type locality: Not stated. Probably named for exposures 

near Mud Spring Creek, sees. 35 and 36, T. 23 N., R. 37 E., 

Clan Alpine Mountains, Churchill County, Nev. 

Muhlenberg Member (Allentown Formation) 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Muleros 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Mullikin 

1. 

2. 

3. 

4. 

7. 

9. 

10. 

Late Cambrian 

Pennsylvania (SE) 

MacLachlan, D. B., 1979, Geology and mineral resources of 

the Temple and Fleetwood quadrangles, Berks County, Pennsylvania: Pennsylvania Geol. Survey, 4th ser., Atlas 187ab, 

p. 15-18 

Limestone, dolomite, sandstone 

Gray 

240 m 

Sandy and carbonate fragments abundant in soil, stromatolitic, oolitic, cyclic deposits 

Conformably overlies Tuckerton Member; conformably underlies 

Maiden Creek Member 

Type locality: Temple quarry of Berks Products Corp., 

Muhlenberg Township, Temple quadrangle, Berks County, Pa. 

Formation 

Early Cretaceous 

New Mexico (SC), Texas, Mexico 

Strain, W. S., 1976, New formation names in the Cretaceous 

at Cerro de Cristo Rey, Dona Ana County, New Mexico, 

Appendix 2, ~Lovejoy, E. M. P., Geology of Cerro de Cristo 

Rey uplift, Chihuahua and New Mexico: New Mexico Bur. Mines 

and Mineral Resources Mem. 31, p. 79-80 

Limestone, interbedded with shale and siltstone 

Olive-gray, yellowish-brown 

32.4 m Limestone nodular, fossiliferous (Texigryphaea in banklike 

layers) 

Conformably overlies Smeltertown Formation; conformably 

underlies Mesilla Valley Shale 

Type section: On N side near head of arroyo trending S 

70° W from kiln area of El Paso Brick Co. plant; 

SE1/4SE1/4NE1/4 sec. 16, T. 29 S., R. 4 E., Smeltertown 

quadrangle, Dona Ana County, N. Mex. Named for Cerro de 

Muleros, original name of Cerro de Cristo Rey. 

Brook Member (Ammonoosuc Formation) 

Middle Ordovician 

New Hampshire (WC) 

Prager, G. D., 1980, Stratigraphy of the Gardner Mountain 

area, New Hampshire: Northeastern Geology, v. 2, no. 1, 

p. 34 

Quartz- and sericite-rich felsite 

Massive, fine-grained, granular 

Underlies West Bath Member 

Type locality: Mullikin Brook, 0.24 km S of New Hampshire 

Route 18, Grayton County, N.H. 

Muncy Till 

1. Pleistocene (Illinoian) 

2. Pennsylvania (C) 

3. Wells, R. B., and Bucek, M. F., 1980, Geology and mineral 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

resources of the Montoursville North and Huntersville quadrangles, Lycoming County, Pennsylvania: Pennsylvania 

Geological Survey, 4th ser., Atlas 143cd, p. 24, 61 

4. Slightly calcareous till consisting of clay, silt, sand, and 

pebbles 

5. Dark-grayish-brown 

6. 12.19 m 

7. Well-compacted, unsorted and nonstratified 

9. Overlies Muncy drift and Paleozoic bedrock; underlies 

Warrensville Till and drift 

10. Type section: Roadcut on U.S. Route 220, 8 km NW of Muncy, 

lat 40°15' 10 11 N., long 76°52'29" W., Montoursville North 

quadrangle, Lycoming County, Pa. 

Murdock Mountain Formation (Park City Group) 

1. Early Permian (Roadian to Wordian) 

2. Nevada (NE), Utah 

3. Wardlaw, B. R., Collinson, J. W., and Maughan, E. K., 1979, 

The Murdock Mountain Formation--a new unit of the Permian 

Park City Group, Chapter B, in Wardlaw, B. R., ed., Studies 

of the Permian Phosphoria Formation and related rocks, Great 

Basin-Rocky Mountain region: U.S. Geol. Survey Prof. Paper 

1163-B, p. 5-8 

4. Dolomitic chert, dolomite, sandstone, siltstone 

5. Gray 

6. 385.5 m 7. Bedded, fossiliferous, slope- and ledge-forming 

9. Conformably and gradationally overlies Meade Peak Phosphatic 

Shale Tongue (Phosphoria Formation); conformably underlies 

Gerster Limestone (Park City Group) 

10. Type section: On E flank of Murdock Mountain, N-center 

sec. 36, T. 39 N., R. 67 E., Leach Mountains, Loray quadrangle, Elko County, Nev. 

Murphy Member (Snake Creek Formation) 

1. Miocene, middle 

2. Nebraska (NW) 

3. Skinner, M. F., Skinner, S. M., and Gooris, R. J., 1977, 

Stratigraphy and biostratigraphy of late Cenozoic deposits 

in central Sioux County, western Nebraska: Am. Mus. Nat. 

History Bull., v. 158, art. 5, p. 308-310 

4. Sand, sandy clay, basal conglomerate 

5. Pink, tan, gray 

6. 9.7 m, range 4.8-9.7 m 7. Consolidated, channel deposit, fossiliferous (vertebrates) 

9. Disconformably overlies Olcott Formation or Sheep Creek 

Formation (Hemingford Group); unconformably underlies 

Laucomer Member or Johnson Member (Snake Creek Formation) 

10. Type section: NE side of Olcott Hill, NE1/4SW1/4SE1/4 

sec. 3, T. 25 N., R. 55 W., near Murphy Ranch, Sioux County, 

Nebr. 

Musinia Peak Member (Flagstaff Limestone) 

1. Eocene, early 

2. Utah (C) 

3. Stanley, K. 0., and Collinson, J. W., 1979, Depositional 

history of Paleocene-lower Eocene Flagstaff Limestone and 

coeval rocks, central Utah: Am. Assoc. Petroleum Geologists 

115 
116 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Bull., v. 63, no. 3, p. 318-319 

Limestone (micrite), interbedded with mudstone 

Bluish-gray, yellowish-brown 

37 m, range 37-50 m 

Fossiliferous (mollusks); represents upper of two major high 

stands of Lake Flagstaff 

Overlies Cove Mountain Member (Flagstaff Limestone); upp~r 

contact nowhere exposed on top of Wasatch Plateau, but on W 

flank conformably underlies Colton Formation 

Type locality: Musinia Peak, E1/2 sec. 28, T. 20 S., 

R. 3 E., Wasatch Plateau, Sanpete County, Utah. 

Muzzy Ridge Member (Appleton Ridge Formation) 

1. Early Devonian 

2. Maine (SC) 

3. Bickel, C. E., 1976, Stratigraphy of the Belfast quadrangle, 

Maine: Geol. Soc. America Mem. 148, p. 109 

4. Cummingtonite-garnet schist with minor biotite, plagioclase, 

quartz, and hornblende 

5. Gray to black, weathers rusty 

7. Fine-grained, dense; weakly schistose 

9. In fault contact with Jam Brook Formation to SW along St. 

George fault 

10. Type locality: Muzzy Ridge, Belfast quadrangle, Waldo 

County, Maine. 

Nagog Pond Gneiss Member (Nashoba Formation) 

1. pre-Silurian 

2. Massachusetts (C) 

3. Bell, K. G., and Alvord, D. C., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 184-185, 208, app. 1 (in pocket) 

4. Sillimanitic biotite gneiss 

5. Medium-gray 

6. 1 ,370 m 

7. Medium-grained, stratified, relict sedimentary structures 

9. Overlies Nashoba Brook Member; underlies Fort Pond Member 

10. Type locality: Area bounded on NW by Nagog Pond, on SW by 

Nagog Brook, on SE by S-flowing tributary to Nagog Brook, 

and on NE by Great Road, all in town of Acton, Westford 

quadrangle, Middlesex County, Mass. 

Nashoba Brook Member (Nashoba Formation) 

1. pre-Silurian 

2. Massachusetts (C) 

3. Bell, K. G., and Alvord, D. C., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 186-187, 208, app. 1 (in pocket) 

4. Calc-silicate rocks, sillimanitic muscovite-biotite schist, 

amphibole-biotite gneiss 

6. 920 m 7. Stratified, relict sedimentary structures 

9. Overlies Tophet Swamp Gneiss Member; underlies Nagog Pond 

Gneiss Member 

10. Type locality: Outcrops near junction of Quarry Road and 

Main Street in town of North Acton, and along Nashoba Brook 

E of this junction, Westford quadrangle, Middlesex County, 

Mass. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Nasset Bentonite Bed (Sherwood Member of Dunleith Formation)/{Loves 

Park Member of Dunleith Formation, in Illinois only) 

1. Middle Ordovician 

2. Iowa (NE), Illinois 

3. Willman, H. B., and Kolat~, D. R., 1978, The Platteville and 

Galena Groups in northern Illinois: Illinois Geol. Survey 

Circ. 502, p. 50 

4. Bentonite clay 

6. 0.07 m 

9. In type section, overlies and underlies limestone units in 

lower part of Sherwood Member 

10. Type section: Engineer& Old Cut section, stream diversion 

channel, 2.4 km W of Decorah, SE1/4NE1/4 sec. 18, T. 98 N., 

R. 8 W., Winneshiek County, Iowa. Named for town of Nasset, 

12.8 km E of type section. 

Revell Sandstone Member (Calabasas Formation) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E23 

4. Sandstone, shaly siltstone, dolomitic concretions in siltstone 

6. 244 m 7. Poorly sorted turbidites 

9. Conformably ~verlies Dry Canyon Sandstone Member (Calabasas 

Formation); intertongues with Malibu Bowl Tongue (Conejo 

Volcanics); conformably unde~lies Mesa Peak Breccia Member 

(Calabasas Formation) 

10. Type area: Newell Road, Santa Monica Mountains, WC Malibu 

Beach quadrangle, Los Angeles County, Calif. 

Newfound 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Member (Doswell Formation) 

Late Triassic 

Virginia (EC) 

Weems, R. E., 1980, Geology of the Taylorsville basin, 

Hanover County, Virginia: Virginia Div. Mineral Resources 

Pub. 27, p. 26-27 

Sandstone-conglomerate facies intertonguing with sandstonesiltstone facies 

Light-brown, light-gray, grayish-orange, red 

513.3 m Massive, crossbedded, alluvial-fan, fluvial, flood-plain 

deposits 

Conformably overlies Falling Creek Member (Doswell Formation); unconformably underlies Miocene to Holocene strata 

Type section: Along Stagg Creek, beginning at Hanover 

Country Club, 0.3 km N of Virginia Highway 54 and continuing 

S to contact with Petersburg Granite, Taylorsville basin, 

Hanover Academy quadrangle, Hanover County, Va. Named for 

Newfound River, tributary of South Anna River. 

New Hanover Member (Castle Hayne Formation) 

1. Eocene, middle (Claibornian) 

2. North Carolina (SE) 

3. Ward, L. W., Lawrence, D. R., and Blackwelder, B. W., 1978, 

117 
118 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Stratigraphic revision of the middle Eocene, Oligocene, and 

lower Miocene---Atlantic Coastal Plain of North Carolina: 

U.S. Geol. Survey Bull. 1457-F, p. F6-F8 

Phosphatic lithocalcirudite 

Cream-colored matrix 

1 m, range <1-2 m 

Arenitic, micrite matrix; cobble- to pebble-sized clasts; 

fossiliferous 

Unconformably overlies and occupies erosional channels in 

Peedee Formation; unconformably underlies Comfort Member 

(Castle Hayne Formation) 

Type locality: Martin Marietta Co. Castle Hayne quarry, 

28 km E of Castle Hayne, 0.8 km north of County Route 1002, 

New Hanover County, N.C. 

New Harmony Group 

1. Early Devonian 

2. Illinois (SE), Indiana 

3. Becker, L. E., and Droste, J. B., 1978, Late Silurian and 

Early Devonian sedimentologic history of southwestern 

Indiana: Indiana Geol. Survey Occasional Paper 24, p. 4-5 

4. Dolomitic limestone and chert 

6. 150 m 

7. Medium- to coarse-grained 

8. Backbone Limestone, Grassy Knob Chert, Clear Creek Chert 

9. Conformably overlies Bailey Limestone (Bainbridge Group); 

unconformably underlies Dutch Creek Sandstone Member 

(Jeffersonville Limestone) 

10. Type section: Superior No. C-17 Ford well, depth-interval 

1520-1670 m, sec. 27, T. 4 S., R. 14 W., White County, 

Ill. Named for town of New Harmony, Ind., across Wabash 

River from well. 

New Shoreham Drift 

1. Pleistocene (late Wisconsinan) 

2. Rhode Island (SC) 

3. Sirkin, Les, 1976, Block Island, Rhode Island--evidence of 

fluctuation of the late Pleistocene ice margin: Geol. Soc. 

America Bull., v. 87, no. 4, p. 574-580 

4. Sand and gravel outwash overlain by till 

6. 20 m 

7. Cross-bedded; morainal topography and drumlin field; derived 

from glacial lobe that crossed Connecticut region 

9. Unconformably overlies Montauk Drift and interstadial 

alluvium deposits 

10. Type section: Not stated. Derivation of name not stated. 

Occurs on Block Island, R.I. 

New Sweden Formation (Perham Group) 

1. Silurian (Llandoverian and Wenlockian) 

2. Maine (NE) 

3. Roy, D. C., and Mencher, Ely, 1976, Ordovician and Silurian 

stratigraphy of northeastern Aroostook County, Maine: Geol. 

Soc. America Mem. 148, p. 38, 49 

4. Calcareous, phyllitic slate containing laminae of calcareous 

siltstone and manganiferous ironstone 

5. Gray 

6. Range 180-1,200 m 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

9. Conformably overlies Spragueville Formation or Carys Mills 

Formation, or disconformably overlies Pyle Mountain 

Argillite; interfingers with Spragueville Formation or 

Frenchville Formation; conformably underlies Jemtland 

Formation (Perham Group) 

10. Type area: Exposed along Maine Route 161 in New Sweden, 

Aroostook County, Maine. 

Rine Hill Tuff 

1. Oligocene 

2. Nevada (WC) 

3. Bingler, E. C., 1978, Abandonment of the name Hartford Hill 

Rhyolite Tuff and adoption of new formation names for middle 

Tertiary ash-flow tuffs in the Carson City-Silver City area, 

Nevada: U.S. Geol. Survey Bull. 1457-D, p. D11-D14 

4. Ash-flow tuff 

5. Pale-orange-red_ to reddish-purple in lower part; pale-brown 

to purplish-brown in upper part 

6. >700 m 

7. Devitrified, densely welded, pumice-rich in lower part; 

vitric, weakly welded, pumice-poor in upper part, which 

locally includes dikes and pluglike masses of very densely 

welded and stretched tuff 

9. Unconformably overlies pre-Tertiary basement rocks and 

Mickey Pass Tuff; disconformably underlies Eureka Canyon 

Tuff and younger Tertiary volcanic rocks; younger than 

Lenihan Canyon Tuff 

10. Type section: Near Nine Hill, NE1/4 sec. 29, T. 16 N., 

R. 20 E., Carson City quadrangle, Washoe County, Nev. 

North Standard Latite (Laguna Springs Volcanic Group) 

1. Oligocene, middle 

2. Utah (C) 

3. Morris, H. T., and Lovering, T. S., 1979, General geology 

and mines of the East Tintic mining district, Utah and Juab 

Counties, Utah: U.S. Geol. Survey Prof. Paper 1024, 

p. 45, 48 

4. Latite flows, tuff, alluvium 

5. Tuff: gray to white; flow: purplish-gray 

6. Tuff: irregular thickness; flow: 91-152 m 

7. Tuff: heterogeneous boulder tuff; flow: medium--grained 

latite vitrophyre B. Informal lower tuff member, upper flow member 

9. Unconformably overlies Latite Ridge Latite (Tintic Mountain 

Volcanic Group), Packard Quartz Latite, or Paleozoic rocks; 

underlies Pinyon Queen Latite (Laguna Springs Volcanic 

Group) 

10. Type locality: Outcrops in area of North Standard shaft, 

sees. 27 and 34, T. 9 S., R. 2 W., East Tintic mining 

district, Utah County, Utah. 

Nugent Tuff Member (Hu-pwi Rhyodacite) 

1. Miocene 

2. Nevada (WC) 

3. Ekren, E. B., 1980, Stratigraphy, preliminary petrology, and 

some structural features of Tertiary volcanic rocks in the 

Gabbs Valley and Gillis Ranges, Mineral County, Nevada: 

U.S. Geol. Survey Bull. 1464, p. 37-38 

119 
120 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

4. Rhyodacitic ash-flow tuff 

5. Gray, brown 

6. Range <1-500 m 

7. Porphyritic, compound cooling unit 

9. Overlies Blue Sphinx Tuff or lava of Nugent Wash; underlies 

Ghost Dance Lava Member or Poinsettia Tuff Member (Hu-pwi 

Rhyodacite), or younger lavas or tuffs 

10. Type locality: Exposures in and near Nugent Wash, T. 11 N., 

R. 32 E., N Gabbs Valley Range, Mineral County, Nev. 

Oahe Formation 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

Oak City 

1 • 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Pleistocene (Wisconsinan) and Holocene 

North Dakota (C) 

Clayton, Lee, Moran, S. R., and Bickley, W. B., Jr., 1976, 

Stratigraphy, origin, and climatic implications of late 

Quaternary upland silt in North Dakota: North Dakota Geol. 

Survey Misc. Ser., no. 54, p. 1-15 

Unlithified silt loam composed of silt, clay, and sand 

Light-gray, light-brown 

3.10 m, range 3.10-6 m Unbedded; vertical columnar jointing; fossiliferous 

Mallard Island, Aggie Brown, Pick City, Riverdale Members 

Overlies glacial sediments; lies at surface 

Type section: Riverdale Section, bluffs of Lake Sakakawea, 

center sec. 22, T. 147 N., R. 84 W., 4 km N of Riverdale, 

McLean County, N. Dak. Named for Oahe Reservoir, Emmons 

County. 

Formation 

Miocene 

Utah (C) 

Campbell, J. A., 1979, Middle to late Cenozoic stratigraphy 

and structural development of the Canyon Range, central 

Utah: Utah Geology, v. 6, no. 1, p. 8-13 

Conglomerate, sandstone, and siltstone 

Pinkish-gray 

45 m 

Bedded, coarse- to fine-grained. Remnants of extensive 

alluvial fan deposits 

Unconformably overlies folded, faulted, and deeply eroded 

early Paleozoic and Tertiary strata; surface is maturely 

dissected and covered by mantle of lag gravel 

Type locality: Exposures on SW facing slope between Oak 

City and Clay Spring Wash, SE1/4NW1/4NW1/4 sec. 20, 

T. 17 s., R. 4 W., Canyon Range, Millard County, Utah. 

Oella Formation (Wissahickon Group) 

1. Cambrian-Ordovician(?) 

2. Maryland (NC) 

3. Crowley, W. P., 1976, The geology of the crystalline rocks near Baltimore and its bearing on the evolution of the 

eastern Maryland Piedmont: Maryland Geol. Survey Rept. 

Inv. 27, p. 11, 24-25 

4. Biotite-plagioclase-muscovite quartz schist, interlayered 

with biotite-plagioclase-quartz gneiss and, locally, epidote 

amphibolite 

6. Range <1-1,300 m 

8. Locally divisible into lower unnamed metasedimentary unit, 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

and (upper) Sweathouse Amphibolite Member 

9. Overlies Loch Raven Schist; underlies Sykesville Formation 

10. Type locality: Outcrops along Patapsco River at Oella, SW 

Baltimore County, Md. 

Olcott Formation (Hemingford Group) 

1. Miocene, middle 

2. Nebraska (NW) 

3. Skinner, M. F., Skinner, S. M., and Gooris, R. J., 1977, 

Stratigraphy and biostratigraphy of late Cenozoic deposits 

in central Sioux County, western Nebraska: Am. Mus. Nat. 

History Bull., v. 158, art. 5, p. 300-306 

4. Quartz sand, silty sand, sandy ash 

5. Buff, brown, gray 

6. 24 m 

7. Fluviatile, massive, well-sorted, fossiliferous (vertebrates) 

9. Unconformably overlies Harrison Formation (Arikaree Group) 

or, locally, Sheep Creek Formation (Hemingford Group); 

disconformably underlies Snake Creek Formation (Ogallala 

Group) 

10. Type section: NE side of Olcott Hill, NW/14SE1/4SE1/4 

sec. 3, T. 25 N., R. 55 W., Sioux County, Nebr. 

Olema Creek Formation 

1. Pleistocene 

2. California (WC) 

3. Galloway, A. J., 1977, Geology of the Point Reyes Peninsula, 

Marin County, California: California Div. Mines and Geology 

Bull. 202, p. 39-40 

4. Clayey siltstone or claystone interbedded with coarse granitic gravel 

5. Light-blue-gray, brownish-gray 

6. >200 m, base not exposed 

7. Thin-bedded, laminated, abundant organic material, freshwater diatoms; confined to central part of San Andreas fault 

zone 

9. Inferred to unconformably overlie serpentine and related 

Franciscan rocks of San Andreas fault zone; underlies 

Quaternary sediments 

10. Type section: Outcrop in Olema Creek between Boyd Stewart 

Ranch and Vedanta retreat, Marin County, Calif. 

Olin Sandstone 

1. Late Cambrian 

2. New York (WC), Pennsylvania 

3. Wagner, W. R., 1976, Growth faults in Cambrian and Lower 

Ordovician rocks of western Pennsylvania: Am. Assoc. 

Petroleum Geologists Bull., v. 60, no. 3, p. 414-427 

4. Sandstone with interbeds of dolomite 

6. 90 m 7. Medium- to coarse-grained, subsurface; beach or barrier bar 

deposit 

9. Overlies Warrior Limestone; underlies Gatesburg Formation 

10. Type section: New York State Natural Gas Corp. Robert Olin 

1 well, depth-interval 3,594-3,684 m, Woodhull Township, 

Steuben County, N.Y. 

121 
122 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Oonatut Granite Complex 

1. Late Cretaceous 

2. Alaska (NC) 

3. Hudson, Travis, 1979, Igneous and metamorphic rocks of the 

Serpentine Hot Springs area, Seward Peninsula, Alaska: U.S. 

Geol. Survey Prof. Paper 1079, p. 12-24 

4. Biotite granite 

5. Gray 

7. Stock, peripheral dikes, tin mineralization 

9. Exposed over area of 70 km2 and to deeper levels than any 

other tin-granites in belt. Intrudes unnamed Precambrian(?) 

and Paleozoic metamorphic rocks with sharp, discordant 

contact 

10. Type locality: Serpentine Hot Springs area in headwater 

region of Serpentine River, Bendeleben D-6 and D-5 quadrangles, NC Seward Peninsula, Alaska. Named for Eskimo word 

for area. 

Orange Mountain Basalt (Newark Supergroup) 

1. Early Jurassic 

2. New Jersey (NE), New York 

3. Olsen, P. E., 1980, The latest Triassic and Early Jurassic 

formations of the Newark Basin (eastern North America, 

Newark Supergroup)--stratigraphy, structure, and corre4. 

6. 

7. 

9. 

10. 

Osborne 

1. 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

lation: New Jersey Acad. Sci. Bull., v. 25, no. 2, p. 32-34 

Tholeiitic basalt flows and interbedded volcaniclastic units 

>50 m, range >50-200 m 

Massive, columnar, vesicular basalt 

Overlies Passaic Formation; underlies Feltville Formation. 

Unit was formerly "first" Watchung Basalt of Darton (1890) 

Type section: Exposures along U.S. Interstate Highway I-280 

at its cut through Orange Mountain, East Orange, Essex 

County, N.J. 

Wash Formation 

Miocene to Pliocene(?) 

Arizona (WC), California 

Davis, G. A., and others, 1980, Mylonitization and detachment faulting in the Whipple-Buckskin-Rawhide Mountains 

terrane, southeastern California and western Arizona: Geol. 

Soc. America Mem. 153, p. 119, 122 

Basal fanglomerates, basalt flows interbedded with agglomerate, tuff, and alluvial-fan deposits; intrusive dikes and 

plugs 

>400 m 

Basal fanglomerates and air-fall tuffs have filled old 

valleys with relief of at least 300 m; unit deposited after 

detachment faulting 

Unconformably overlies Gene Canyon and Copper Basin 

Formations and older crystalline rocks 

Type section: Not stated. Widespread exposures in W 

Buckskin Mountains, Yuma County, Ariz., and in SE Whipple 

Mountains, San Bernardino County, Calif. Probably named for 

exposures in hills near Osborne Wash, where Arizona Highway 

95 bridges the wash NE of Parker, Yuma County. 

Otter Creek Microdiorite 

1. Cambrian 
2. 

3. 

4. 

5. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Oklahoma (C) 

Powell, B. N., Gilbert, M. C., and Fischer, J. F., 1980, 

Lithostratigraphic classification or basement rocks of the 

Wichita province, Oklahoma: Summary: Geol. Soc. America 

Bull., pt. 1, v. 91, no. 9,. p. 510-513 

Diorite, quartz-diorite 

Dark-greenish-gray 

Aphanitic, dikes, sills, irregular intrusions 

Intrudes Glen Mountains Layered Complex and Roosevelt 

Gabbros (Raggedy Mountain Gabbro Group) 

Type area: Outcrops near Otter Creek, sec. 15, T. 4 N., 

R. 17 W., Glen Mountains~ Kiowa County, Okla. 

Pacific Ridge Complex 

1. Early Cretaceous or older 

2. California (NW) 

3. Suppe, John, and Foland, K. A., 1978, The Goat Mountain 

Schists and Pacific Ridge Complex--a redeformed but stillintact late Mesozoic Franciscan schuppen complex, in Howell, 

D. G., and McDougall, K. A., eds., Mesozoic paleogeography 

of the western United States--Pacific Coast Paleogeography 

Symposium 2 [Sacramento, Calif., 1978]: Los Angeles, Soc. 

Econ. Paleontologists and Mineralogists, Pacific Sec., 

p. 431-451 

4. Interbedded metacherts, metagraywackes, metamudstones, and 

metavolcanic rocks 

9. Structurally interlayered with Goat Mountain Schists in 

Franciscan terrane 

10. Type area: 400-1,000 m along ridge extending NW from Goat 

Mountain summit, lat 39°01 N.~ long 122°45'- W., Stonyford 

quadrangle, Lake County, Calif. 

Page Sandstone (San Rafael Group) 

1. Middle Jurassic (Bajocian and Bathonian) 

2. Arizona (NC), Utah 

3. Peterson, Fred, and Pipiringos, G. N., 1979, Stratigraphic 

relations or the Navajo Sandstone to Middle Jurassic formations in parts of southern Utah and northern Arizona: U.S. 

Geol. Survey Prof. Paper 1035-B, p. B20-B30 

4. Sandstone containing angular chert pebbles at base 

5. Red-orange, red-brown, light-gray 

6. 55.8 m, range <1-88.7 m 7. Fine-grained, well-sorted, crossbedded, cliff-forming 

8. Harris Wash Tongue at base, Thousand Pockets Tongue 

9. Unconformably overlies Navajo Sandstone (Glen Canyon Group); 

intertongues with Judd Hollow Tongue (Carmel Formation of 

San Rafael Group), which splits into Harris Wash and 

Thousand Pockets Tongues; underlies informal upper member of 

Carmel Formation -

10. Type section: NW side or Manson Mesa on which town of Page is situated, SW1/4NW1/4 sec. 19, T. 41 N., R. 9 E., Coconino 

County, Ariz. 

Pabruap Hills Shale Member (Carrara Formation) 

1. Middle Cambrian 

2. Nevada (SC), California 

3. Palmer, A. R., and Halley, R. B., 1979, Physical stratigraphy and trilobite biostratigraphy of the Carrara Formation 

123 
124 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

(Lower and Middle Cambrian), southern Great Basin: U.S. 

Geol. Survey Prof. Paper 1047, p. 18-20 

Siltstone, mudstone, shale, minor limestone and sandstone 

Tan, red, green 

Range <1-94 m Thin-bedded, fossiliferous, terrigenous clastic deposits 

Overlies with sharp contact Red Pass Limestone Member; 

conformably and gradationally underlies Jangle Limestone 

Member 

Type locality: Exposures in Pahrump Hills, NW of Pahrump, 

Nye County, Nev. 

Pamlico Formation 

1. Triassic 

2. Nevada (WC) 

3. Oldow, J. s., 1978, Triassic Pamlico Formation--an allochthonous sequence of volcanogenic-carbonate rocks in westcentral Nevada, in Howell, D. G., and McDougall, K. A., 

eds., Mesozoic paleogeography of the western United States--

Pacific Coast Paleogeography Symposium 2 [Sacramento, 

Calif., 1978]: Los Angeles, Soc. Econ. Paleontologists and 

Mineralogists, Pacific Sec., p. 223-235 

4. Limestone with interbedded volcanic and volcanogenic sedi6. 

7. 

8. 

9. 

10. 

Panther 

1 • 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

Parkers 

1. 

2. 

3. 

mentary rocks 

>1,500 m 

Limestone, medium- to coarse-grained, uniformly bedded; 

superimposed fold sets, high-angle faults 

Informal lower, middle, and upper members comprising 21 

mappable lithologic units 

Base not observed; conformably underlies undifferentiated 

Sunrise and Gabbs Formations; in E Garfield Hills, thrust 

nappes of Pamlico and Dunlap Formations structurally intercalated 

Type locality: Pamlico mining district, W Garfield Hills, 

Mineral County, Nev. 

Camp Formation (Naples Bay Group) 

Early Cretaceous (Comanchean) 

Florida (SE) 

Winston, G. D., 1976, Six proposed formations in the 

undefined portion of the Lower Cretaceous section in south 

Florida: Gulf Coast Assoc. Geol. Socs. Trans., v. 26, p. 71 

Limestone with thick anhydrite beds 

95 m 

Porous pelletal limestone at base, regionally persistent 

anhydrite bed at top 

Overlies Gordon Pass Formation (Big Cypress Group); underlies Rookery Bay Formation (Naples Bay Group) 

Type section: Humble No. 1 Collier Corp. well, depthinterval 3,002 m, sec. 27, T. 50S., R. 26 E., Collier 

County, Fla. Named for Panther Camp, 12.8 km N of type 

well. 

Ferry Heaber (Cooper Formation) 

Eocene, late 

South Carolina (SC) 

Ward, L. W., and others, 1979, Stratigraphic revision of 

Eocene, Oligocene, and lower Miocene formations of South 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Carolina: South Carolina Geol. Survey Geol. Notes, v. 23, 

n.o. 1, p. 23-24 

4. Glauconitic, clayey limestone 

5. Grayish-yellow-green, yellowish-gray, or pale-olive 

6. 2.5 m, range 2.5-40 m 

7. Fine-grained, fossiliferous; known only in subsurface 

9. Unconformably overlies Harleyville Member; unconformably 

underlies Ashley Member 

10. Type section: Clubhouse Crossroads Corehole 1, depthinterval 54.5-57 m, in Drayton Swamp, 3.5 km SW of Clubhouse 

Crossroads, Cottageville 15' quadrangle, Dorchester County, 

S.C. Type area: Drill holes SW to NE along E side of 

Edisto River between Parkers Ferry and Ponpon on U.S. 

Highway 17, Charleston County, and Sullivans Ferry on U.S. 

Highway 17A, Dorchester County, S.C. 

Parkman Hill Formation 

1. Middle and Late Silurian (Wenlockian to Ludlovian) 

2. Maine (WC) 

3. Pankiwskyj, K. A., and others, 1976, Stratigraphic relationships on the southeast limb of the Merrimack synclinorium in 

central and west-central Maine: Geol. Soc. America Mem. 

146, p. 269, 274-275 

4. Sulfidic carbonaceous metapelite, quartz-rich granule metaconglomerate and metasandstone, and nonsulfidic metasandstone 

5. Weathers rusty 

6. 200-300 m, range 200-700 m 

7. Fossiliferous (graptolites) 

9. Overlies and interfingers with Sangerville Formation; underlies Fall Brook Formation 

10. Type locality: S and SE slopes of Parkman Hill, NE Anson 

quadrangle, Somerset County, Maine. 

Passaic 

1 • 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

Formation (Newark Supergroup) 

Late Triassic and Early Jurassic 

New Jersey (NE), New York, Pennsylvania 

Olsen, P. E., 1980, The latest Triassic and Early Jurassic 

formations of the Newark Basin (eastern North America, 

Newark Supergroup)--stratigraphy, structure, and correlation: New Jersey Acad. Sci. Bull., v. 25, no. 2, p. 29-32 

Siltstone, sandstone, conglomerate, and periodically spaced 

bundles of detrital cyclic non-red units 

Red 

>6,000 m max 

Cut by diabase intrusions and dikes 

Perkasie Member 

Conformably overlies Lockatong Formation; underlies Orange 

Mountain Basalt. Unit was formerly lower part of Brunswick 

Formation of Kummel (1897) 

Type section: Intermittent exposures along U.S. Highway 

I-80 near Passaic, Passaic County, N.J. 

Pastillo Member (Lago Garzas Formation) 

1. Late Cretaceous (Campanian(?) and Maestrichtian) 

2. Puerto Rico (SC) 

3. Krushensky, R. D., and Monroe, W. H., 1978, Geology of the 

Penuelas and Punta Cuchara quadrangles, Puerto Rico: U.S. 

125 
126 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Geol. Survey Misc. Inv. Ser., Map I-1042 

Volcaniclastic andesite breccia interbedded with lava flows 

and minor fine-grained marine sedimentary rocks 

Dark-red, purple, green 

>1,000 m Thick-bedded to massive, deeply saprolitized locally 

Conformably overlies and interbedded with Yauco Formation; 

interbedded with and underlies Santas Pascuas Member (Lago 

Garzas Formation) 

Type area: Near headwaters of Rio Pastille, near Marueno, 

P.R. 

Paxson Mountain Basalt (Amphitheater Group) 

1. Triassic 

2. Alaska (EC) 

3. Stout, J. H., 1976, Geology of the Eureka Creek area, eastcentral Alaska Range: Alaska Div. Geol. and Geophys. 

Surveys Geol. Rept. 46, p. 10-12 

4. Basalt, amygdaloid basalt 

5. Olive-gray to dark-green, maroon 6. Range 1,500-3,000 m 

7. Oldest unit in E-W Amphitheater syncline 

9. Overlies Mankomen Group; underlies Tangle Lakes Formation 

(Amphitheater Group); intruded by Fish Lake Complex 

10. Type locality: Paxson Mountain, Eureka Creek area, Mount 

Hayes A-4 quadrangle, EC Alaska Range, Alaska. 

Perry Hall Gneiss 

1. Cambrian-Ordovician(?) 

2. Maryland (NC) 

3. Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the 

eastern Maryland Piedmont: Maryland Geol. Survey Rept. 

Inv. 27, p. 17-18, 30 

4. Biotite-quartz-plagioclase gneiss interlayered with hornblende-quartz-plagioclase gneiss 

9. Overlies Bradshaw Layered Amphibolite and Raspeburg Amphibolite (Baltimore Mafic Complex) in NE-SW syncline 

10. Type locality: Outcrops along Bel Air Road N of Perry Hall, 

along NE-flowing tributary of Gunpowder Falls, and in 

abandoned quarry 450 m NE of Gunpowder Falls, White Marsh 

quadrangle, Baltimore County, Md. 

Persimmon 

1 • 

2. 

3. 

4. 

6. 

7. 

8. 

9. 

Creek Gneiss (Coweeta Group) 

Precambrian, late(?) (Late Proterozoic(?)] 

Georgia (NC), North Carolina 

Hatcher, R. D., Jr., 1979, The Coweeta Group and Coweeta 

syncline--major features of the North Carolina-Georgia Blue 

Ridge: Southeastern Geology, v. 21, no. 1, p. 21 

Orthoclase-quartz-biotite gneiss, massive (lower member) or interlayered with metasandstone and biotite-muscovite-quartz 

schist 

Range 1,300-2,000 m Massive to interlayered, coarse, even-grained texture, forms 

exfoliated cliffs 

Informal lower and upper members 

Overlies Tallulah Falls Formation; underlies Coleman River 

Formation (Coweeta Group) 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

10. Type area: Exposures along Persimmon Creek, Dillard quadrangle, NW Rabun County, Ga. 

Petrified Spring Tuff (Benton Spring Group) 

1. Oligocene 

2. Nevada (WC) 

3. Ekren, E. B., and others, 1980, Stratigraphy, preliminary 

petrology, and some structural features of Tertiary 

volcanics rocks in the Gabbs Valley and Gillis Ranges, 

Mineral County, Nevada: U.S. Geol. Survey Bull. 1464, 

p. 28-29 

4. Rhyodacite and quartz latite tuff 

6. 75 m, range <1-75 m 

7. Multiple-flow simple cooling unit 

9. Overlies Singatse Tuff (Benton Spring Group) or unnamed ashflow cooling units; underlies Blue Sphinx Tuff 

10. Type locality: Exposure 4 km S of Petrified Spring, NW1/4 sec. 31, T. 9 N., R. 35 E., S Gabbs Valley Range, Mineral 

County, Nev. 

Phantom Lake Suite 

1. Early Proterozoic 

2. Wyoming (SE) 

3. Karlstrom, K. E., and Houston, R. S., 1979, Stratigraphy and 

uranium potential of Early Proterozoic metasedimentary rocks 

in the Medicine Bow Mountains, Wyoming: Wyoming Geol. 

Survey Rept. Inv. 13, p. 9-11 

4. Metavolcanic and metasedimentary rocks including quartzite 

and radioactive conglomerate 

6. 3,000 m 

7. Tabular cross-bedding; depositional environments include 

subaerial, fluvial, and shallow marine 

8. Lower volcanogenic sequence; upper fluvial and shallow 

marine sequence including, at top, informal Arrastre 

volcanics 

9. Unconformably overlies Archean granitic rocks; unconformably 

underlies Magnolia Formation (Deep Lake Group) 

10. Type area: S of Phantom Lake, T. 16 N., R. 79 W.; along 

North Fork of Rock Creek, T. 17 N., R. 79 W.; and NW1/4 

sec. 23, T. 16 N., R. 81 W., Medicine Bow Mountains, Carbon 

County, Wyo. 

Piatt Till Member (Wedron Formation) 

1. Pleistocene 

2. Illinois (EC) 

3. Wickham, J. R., 1979, Glacial geology of north-central and 

western Champaign County, Illinois: Illinois Geol. Survey 

Circ. 506, p. 6-7 

4. Loam till 

5. Gray 

6. 2.7 m 

9. Overlies Fairgrange Till Member; underlies Batestown Till 

Member 

10. Type section: Mahomet I-74 Bridge Section, E bank of Sangamon River, N of U.S. Highway I-74, NE1/4SE1/4NE1/4 sec. 15, 

T. 20 N., R. 7 E., Champaign County, Ill. Named for Piatt 

County. 

127 
128 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Pick City Member (Oahe Formation) 

1. Holocene 

2. North Dakota (C) 

3. Clayton, Lee, Moran, S. R., and Bickley, W. B., Jr., 1976, 

Stratigraphy, origin, and climatic implications of late 

Quaternary Upland silt in North Dakota: North Dakota Geol. 

Survey Misc. Ser., no. 54, p. 5-6 

4. Silt, clay, and sand 

5. Light-gray 

6. 0.7 m 

9. Overlies Aggie Brown Member; underlies Riverdale Member 

10. Type section: Riverdale Section, bluffs of Lake Sakakawea, 

center sec. 22, T. 147 N., R. 84 W., McLean County, N. 

Oak. Named for village of Pick City, 8 km SW of Riverdale 

Section. 

Pierz Granite 

1. Precambrian, middle 

2. Minnesota (C) 

3. Morey, G. B., 1978, Lower and middle Precambrian stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol. Survey Rept. Inv. 21, p. 38 

4. Granite 

5. Light-gray 

7. Fine- to medium-grained, equigranular, elliptical pluton 

9 km long and 3 km wide 

9. Intrudes Hillman Migmatite 

10. Type locality: Abandoned quarry, SE1/4 sec. 13, T. 40 N., 

R. 31 W., Morrison County, Minn. Named for Pierz Lake, 3 km 

W of city of Pierz. 

Piney Run 

1. 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

Formation (Wissahickon Group) 

Cambrian-Ordovician(?) 

Maryland (NC) 

Crowley, W. P., 1976, The geology of the crystalline rocks near Baltimore and its bearing on the evolution of the 

eastern Maryland Piedmont: Maryland Geol. Survey Rept. 

Inv. 27, p. 11 , 25 

Plagioclase-chlorite-muscovite-quartz schist interlayered 

with biotite quartzite 

Range < 1 -2 , 1 00 m Fine-grained 

Overlies Loch Raven Schist; underlies Sykesville Formation 

Type locality: Outcrops along 1.7 km stretch of Piney Run 

and tributaries near Dover Church, we Baltimore County, Md. 

Pinyon Creek Conglaaerate 

1. Miocene, early 

2. Utah (C) 

3. Morris, H. T., and Lovering, T. S., 1979, General geology 

and mines of the East Tintic mining district, Utah and Juab 

Counties, Utah: U.S. Geol. Survey Prof. Paper 1024, 

p. 60-61 

4. Conglomerate 

5. Grayish-tan, reddish, purplish-brown 

6. Range 5->305 m 7. Lenses and beds, great range in size of rock fragments, 

alluvial fan deposits 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

9. Disconformably overlies Pinyon Queen Latite (Laguna Springs 

Volcanic Group), Latite Ridge Latite (Tintic Mountain 

Group), or Packard Quartz Latite; disconformably underlies 

Silver Shield Quartz Latite 

10. Type locality: Exposures in lower Pinyon Creek Canyon, N1/2 

sec. 35, T. 9 S., R. 2 W., NE.East Tinti~mining district, 

Utah County, Utah. 

Pinyon Queen Latite (Laguna Springs Volcanic Group) 

1. Oligocene, middle 

2. Utah (C) 

3. Morris, H. T., and Lovering, T. S., 1979, General geology 

and mines of the East Tintic mining district, Utah and Juab 

Counties, Utah: U.S. Geol. Survey Prof. Paper 1024, 

p. 48-52 

4. Latite flows, tuff, breccia, agglomerate 

5. Flow: dark-reddish-brown 

6. Tuff: range 0.15-122 m; flow: 213m 

7. Tuff: fine-grained to boulder agglomerate; flow: mediumto coarse-grained, massive, porphyritic 

8. Informal lower tuff member and upper flow member 

9. Unconformably overlies North Standard Latite (Laguna Springs 

Volcanic Group), Big Canyon or Latite Ridge Latites (Tintic 

Mountain Volcanic Group), or Packard Quartz Latite; underlies Tintic Delmar Latite (Laguna Springs Volcanic Group) or disconformably underlies Pinyon Creek Conglomerate 

10. Type locality: Exposures E of Pinyon Queen shaft, sees. 34 

and 35, T. 9 S., R. 2 W., East Tintic mining district, Utah 

County, Utah. 

Pitabaya Formation 

1. Early Cretaceous 

2. Puerto Rico (EC) 

3. M'Gonigle, J. W., 1977, The Rio Abajo, Pitahaya, and Daguao 

Formations in eastern Puerto Rico: U.S. Geol. Survey Bull. 

1435-B, p. B6-B7 

4. Lava, autoclastic breccia, tuff and tuff breccia; volcanic 

sandstone 

5. Dark-greenish-gray to olive or brownish-black lava, mediumto brownish-gray tuff and sandstone 

6. 2,000 m 

9. In fault contact with Rio Abajo Formation, but may uncon- formably overlie it W of study area; in intrusive contact 

with Tertiary(?) plutonic rocks of San Lorenzo batholith; 

unconformably underlies Quaternary deposits 

10. Type area: Exposures along Route 926 W from Pitahaya and N 

along Route 937 (extended) along side of Cerro Colloras 

towards town of Melillas, from 38,900 N. and 216,300 E. to 

40,700 N. and 215,900 E., around town of Pitahaya, Municipio 

de Humacao, Humacao quadrangle, P.R. 

Piuaa Member (Sespe Formation) 

1. Miocene, early 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E10-E11 

129 
130 

4. 

5. 

6. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Sandstone and sandstone-mudstone sequence 

Gray, grayish-red, olive-gray 

342 m 

Conformably overlies undivided Sespe Formation; intertongues 

with undivided Vaqueros Formation; conformably underlies 

Saddle Peak Member (Topanga Canyon Formation) 

Type locality: Exposures in Piuma Road and at head of 

Carbon Canyon, NE1/4 sec. 21, T. 1 S., R. 17 W., Santa 

Monica Mountains, EC Malibu Beach quadrangle, Los Angeles 

County, Calif. 

Placer River Silt 

1. Holocene 

2. Alaska (C) 

3. Ovenshine, A. T., Lawson, D. E., and Bartsch-Winkler, s. R., 

1976, The Placer River Silt--an intertidal deposit caused by 

the 1964 Alaska Earthquake: U.S. Geol. Survey Jour. 

Research, v. 4, no. 2, p. 151-162 

4. Micaceous silt of quartz and feldspar with intercalated 

silty clay or fine-grained sand 

5. Olive-gray 

6. 1.18 m average, 1.07 m 

7. Medium- and coarse-silt-size grains, thin-bedded to laminated 

9. Overlies soil horizon rich in organic material; in 1973 

Placer River Silt was still being deposited 

10. Type section: Exposure in N bank of N fork of Portage Creek 

W of Seward Highway, Portage, Alaska. Named for occurrence 

on Placer River. 

Plantation Tongue (Rebecca Shoal Dolomite) 

1. Late Cretaceous 

2. Florida (SE) 

3. Winston, G. 0., 1978, Rebecca Shoal reef-complex (Upper 

Cretaceous and Paleocene) in south Florida: Am. Assoc. 

Petroleum Geologists Bull., v. 62, no. 1, p. 124-127 

4. Anhedral dolomite 

5. Brown, cream 6. 218 m 

7. Subsurface barrier-reef complex; fine crystalline texture 

9. Overlies Card Sound Dolomite; interfingers with Pine Key 

10. 

Pleasant 

1. 

2. 

3. 

4. 

6. 

Formation; underlies Tavernier Tongue (Rebecca Shoal 

Dolomite) 

Type section: Coastal Petroleum 1 State well 363, depthinterval 1,527-1,745 m, sec. 32, T. 62 S., R. 38 E., Monroe 

County, Fla. Named for town of Plantation, 3.2 km S of 

well. 

Grove Schist (Wissahickon Group) 

Cambrian-Ordovician(?) 

Maryland (NC) 

Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the 

eastern Maryland Piedmont: Maryland Geol. Survey Rept. 

I nv. 27 , p • 12 

Plagioclase-chlorite-muscovite-quartz schist, locally with 

magnetite 

Range <1-2,200 m 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

7. Uniform, fine-grained 

9. Overlies Piney Run Formation or Oella Formation; underlies 

Prettyboy Schist 

10. Type locality: Outcrops along McGill Run and SE-flowing 

tributary W and S of Pleasant Grove Church, WC Baltimore 

County, Md. 

Poinsettia Turf Ma.ber (Hu-pwi Rhyodacite) 

1. Miocene 

2. Nevada (WC) 

3. Ekren, E. B., and others, 1980, Stratigraphy, preliminary 

petrology, and some structural features of Tertiary volcanic 

rocks in the Gabbs Valley and Gillis Ranges, Mineral County, 

Nevada: U.S. Geol. Survey Bull. 1464, p. 40-41 

4. Rhyodacite and quartz latite welded tuff 

5. Gray, reddish-gray, brown 

6. Range <1-500 m 1. Porphyritic, multiple-flow simple cooling units 

•9. Overlies Nugent Tuff Member (Hu-pwi Rhyodacite) or lava of 

Poinsettia Spring area (informal member of Hu-pwi Rhyodacite); underlies lava of Mount Ferguson or tuff of Copper 

Mountain 

10. Type locality: Exposures in T. 10 N., R. 33 E., 2 km SSE of 

Poinsettia Spring, N Gabbs Valley Range, Mineral County, 

Nev. 

Point Reyes Conglomerate 

1 • Paleocene 

2. California (WC) 

3. Galloway, A. J., 1977, Geology of the Point Reyes Peninsula, 

Marin County, California: California Div. Mines and Geology 

Bull. 202, p. 18-19 

4. Coarse conglomerate of granitic rocks in matrix of granitic 

sand, interbedded with silty, micaceous sand 

6. >200 m, range >200-400 m, top eroded 

7. Forms craggy or stacklike outcrops with vertical jointing 

9. Unconformably overlies granitic basement rocks; unconformably underlies Drakes Bay Formation 

10. Type section: Outcrops at lighthouse on Wend of Point 

Reyes, Marin County, Calif. 

Pollocksville Member (Belgrade Formation) 

1. Miocene, early 

2. North Carolina (EC) 

3. Ward, L. W., Lawrence, D. R., and Blackwelder, B. W., 1978, 

Stratigraphic revision of the middle Eocene, Oligocene, and 

lower Miocene--Atlantic Coastal Plain of North Carolina: 

U.S. Geol. Survey Bull. 1457-F, p. F14-F15 

4. Oyster-shell bed 

5. Tan to orange 

6. 4 m 

1. Leached, unconsolidated, sandy Crassostrea bed; nearshore 

equivalent of offshore Haywood Landing Member 

9. Unconformably overlies and occupies channels in River Bend 

Formation; upper contact covered 

10. Type locality: Exposures on L bank of Trent River next to 

Seaboard Coastline Railroad trestle, Pollocksville, Jones 

County, N.C. 

131 
132 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Poquoson 

1. 

2. 

3. 

Member (Tabb Formation) 

Pleistocene, late 

Virginia (SE) 

Johnson, G. H., 1976, Geology of the Mulberry Island, 

Newport News North, and Hampton quadrangles, Virginia: 

4. 

5. 

6. 

7. 

9. 

10. 

Virginia Div. Mineral Resources Rept. Inv. 41, p. 37-39 

Silty, clayey, and gravelly sand 

Gray, yellowish-brown 

3.31 m 

Beach and nearshore marine and fluvial-estuarine deposits 

Unconformably overlies Lynnhaven Member (Tabb Formation), 

Norfolk Formation, or Yorktown Formation 

Type section: Hand-auger boring, S side of lane 0.16 km SW 

of Poquoson Avenue and 0.75 km NW of Amorys Wharf, City of 

Poquoson, Va. Named for the city. 

Po River Metamorphic Suite (Fredericksburg Complex) 

1. Late Proterozoic and (or) Paleozoic, early 

2. Virginia (EC) 

3. Pavlides, Louis 1980, Revised nomenclature and stratigraphic 

relationships of the Fredericksburg Complex and Quantico 

Formation of the Virginia Piedmont: U.S. Geol. Survey Prof. 

Paper 1146, p. 4-7 

4. Biotite gneiss, augen gneiss, schist, granitoid and pegmatoid bodies 

5. 

7. 

9. 

10. 

Portage 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Dark 

Layered, foliated 

Base not exposed; in contact with Ta River Metamorphic Suite 

along Spotsylvania lineament; intruded by Falls Run Granite 

Gneiss 

Composite type area: Along Po River between Spotsylvania 

lineament and U.S. Route 1, and along Ni River between Spotsylvania lineament and U.S. Route 1, Spotsylvania quadrangle, Spotsylvania County, Va. 

Canyon Member (Laketown Dolostone) 

Middle Silurian 

Utah (NW), Nevada 

Budge, D. R., and Sheehan, P. M., 1980, The Upper Ordovician 

through Middle Silurian of the eastern Great Basin--Pt. 1, 

Introduction--historical perspective and stratigraphic 

synthesis; Pt. 2, Lithologic descriptions: Milwaukee Public 

Mus. Contr. Biology and Geology, no. 28, p. 20 (pt. 1); 

no. 29, p. 76-77 (pt. 2) 

Dolomite 

Brownish-gray 

61 m 

Finely crystalline, medium- to thick-bedded 

Overlies Gettel Member or High Lake Member; underlies Jack 

Valley Member or Decathon Member 

Type section: Near mouth of Portage Canyon, on Samaria 

Mountain, 3.2 km W of Portage, T. 14 N., R. 4 W., West 

Hills, Bear River Range, Box Elder County, Utah. 

Potato Canyon Rhyolite 

1. Oligocene 

2. New Mexico (WC) 

3. Deal, E. G., and Rhodes, R. C., 1976, Volcano-tectonic 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

structures in the San Mateo Mountains, Socorro County, New 

Mexico: New Mexico Geol. Soc. Spec. Pub. 5, p. 54-55 

4. Rhyolite ash-flow tuff with numerous phenocrysts 

5. Reddish-brown 

6. 1,700 m 7. Massive, densely welded; erupted from Mount Withington 

cauldron 

9. Overlies A-L Rhyolite; unconformably underlies Beartrap 

Canyon Formation 

10. Type locality: Potato Canyon, N San Mateo Mountains, 

sec. 12, T. 5 S., R. 6 W., Socorro County, N. Mex. 

Powers Ferry Formation (Sandy Springs Group) 

1. Precambrian, late(?) and (or) Paleozoic, early(?) 

2. Georgia (NW) 

3. Higgins, M. W., and McConnell, K. I., 1978, The Sandy 

Springs Group and related rocks in the Georgia Piedmont--

nomenclature and stratigraphy: U.S. Geol. Survey Bull. 

1457-A, p. A101-A103 (Also published in: Georgia Geol. 

Survey Bull. 93, p. 51-52, 1978) 

4. Biotite-oligoclase-microcline gneiss with intercalated 

muscovite-biotite schist and amphibolite 

5. Gray 

6. >1,000 m 

7. Isoclinally folded, present only in cores of antiforms 

8. Mableton Amphibolite Member 

9. Apparently oldest formation in Sandy Springs Group, base not 

exposed; underlies in sharp contact (unconformably?) Chattahoochee Palisades Quartzite 

10. Type section: Exposures along Anneewakee Creek and along 

road leading to Camp Anneewakee, Campbellton quadrangle. 

Type area: Exposures in new cuts in Powers Ferry Landing 

shopping center and office park, Sandy Springs quadrangle, 

Fulton County, Ga. 

Prater Creek Asb-tlov Tuff 

1. Miocene, late 

2. Oregon (EC) 

3. Walker, G. W., 1979, Revisions to the Cenozoic stratigraphy 

of Harney basin, southeastern Oregon: U.S. Geol. Survey 

Bull. 1475, p. 20-23 

4. Tuff 

5. Pale-grayish-red 

6. 12 m, range 12-30 m 7. Devitrified, crystal-poor, with abundant grayish-pink 2-cm 

or smaller lithophysae 

9. Overlies unnamed tuffaceous sedimentary rocks which overlie 

Devine Canyon Ash-flow Tuff; underlies unnamed tuffaceous 

sedimentary rocks and basalt which underlie Rattlesnake Ashflow Tuff 

10. Type section: Exposures on walls of Poison Creek, adjacent 

to U.S. Highway 395, 11 to 12 km N of Burns, lat 43°41' N., 

long 119° W., Harney County, Oreg. Named for exposures 

along Prater Creek, 17 km NE of Burns. 

Preakness Basalt (Newark Supergroup) 

1. Early Jurassic 

2. New Jersey (NE), New York 

133 
134 

3. 

4. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Olsen, P. E., 1980, The latest Triassic and Early Jurassic 

formations of the Newark Basin (eastern North America, 

Newark Supergroup)--stratigraphy, structure, and correlation: New Jersey Acad. Sci. Bull., v. 25, no. 2, p. 34-36 

Extrusive, thick tholeiitic basalt flows and interbedded 

volcaniclastic siltstone 

500 m 

Basalt is coarse-grained and jointed 

Overlies Feltville Formation; underlies Towaco Formation. 

Unit was formerly "second" Watchung Basalt of Darton (1890) 

Type section: Exposure along U.S. Highway I-280, 2.25 km W 

of Orange Mountain Basalt type section. Named for Preakness 

Mountain, local name of Second Watchung Mountain, near 

Franklin Lakes, Essex County, N.J. 

Prentiss Creek Member (Bush Bay Dolostone) 

1. Middle Silurian (Niagaran) 

2. Michigan (EC) 

3. Johnson, A. M., and others, 1979, The Maple Block knoll reef 

in the Bush Bay Dolostone (Silurian, Engadine Group), 

Northern Peninsula of Michigan: Michigan Univ. Mus. Paleontology Papers on Paleontology, no. 20, p. 14 

4. Dolomite, chert 

5. Gray to brown 

6. 8 m 

7. Thin- to medium-bedded, fine- to medium-crystalline, organic 

reef, fossiliferous 

9. Overlies Rapson Creek Dolostone; underlies Swede Road Member 

(Bush Bay Dolostone) 

10. Type locality: Cedarville quarry of U.S. Steel Corp., 

Mackinac County, Mich. Named for Prentiss Creek, which 

flows into Prentiss Bay about 9 km E of Cedarville. 

Prettyboy 

1 • 

2. 

3. 

4. 

7. 

9. 

10. 

Schist (Wissahickon Group) 

Cambrian-Ordovician(?) 

Maryland (NC) 

Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the 

eastern Maryland Piedmont: Maryland Geol. Survey Rept. 

Inv. 27, p. 12 

Plagioclase-chlorite-muscovite-quartz schist, commonly with 

albite porphyroblasts and magnetite 

Uniform, fine-grained 

Overlies Pleasant Grove Schist (Wissahickon Group); upper 

contact not stated 

Type locality: Outcrops near dam at Prettyboy Reservoir, 

Hereford quadrangle, Baltimore County, Md. 

Principio Creek Member (James Run Formation) 

1. Paleozoic, early 

2. Maryland (NE) 

3. Higgins, M. W., 1977, Six new members of the James Run 

Formation, Cecil County, northeastern Maryland: U.S. Geol. 

Survey Bull. 1435-A, p. A126-A127 

4. Biotite-feldspar schist, possibly meta-andesite, with relict 

plagioclase phenocrysts, and epidosite inclusions, and metavolcanic rocks 

5. Dark-gray, dark-green 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

6. 610 m 

7. Medium-grained 

9. Underlies unnamed felsite member or James Run Formation; 

probably partly equivalent to parts of Happy Valley Branch 

Member and parts or Port Deposit Gneiss 

10. Type section: Exposures along Principia C~ek NW or Port 

Deposit Road, Cecil County, Md. 

Principio Furnace Member (James Run Formation) 

1. Paleozoic, early 

2. Maryland (NE) 

3. Higgins, M. W., 1977, Six new members of the James Run 

Formation, Cecil County, northeastern Maryland: U.S. Geol. 

Survey Bull. 1435-A, p. A125-A126 

4. Intermediate to felsic metavolcanic rocks with relict 

phenocrysts or plagioclase, quartz, and amphibole; and 

diamictites 

5. Dark- to light-gray to white 

6. 760 m 

7. Interbedded, multiply folded 

9. Gradationally underlies Frenchtown Member; probably partly 

equivalent to Little Northeast Creek Member 

10. Type section: Exposures in Principia Creek from just S or Maryland Highway 7 to just N of U.S. Highway 40, Cecil 

County, Md. Named for Principia Furnace on Principia Creek, 

Cecil County. 

Prow Pass Member (Crater Flat Tuff) 

1. Miocene 

2. Nevada (SC) 

3. Byers, F. M., Jr., and others, 1976, Volcanic suites and 

related cauldrons or Timber Mountain-Oasis Valley caldera 

complex, southern Nevada: U.S. Geol. Survey Prof. Paper 

919, p. 14-15 

4. Ash-flow turr 

5. Light-gray, grayish-pink, or orange-pink where devitrified; 

light-brown where glassy 

6. 15.2 m, range 15-50 m 7. Glassy, devitrified, welded, single cooling unit phenocryst 

9. Overlies Bullfrog Member (Crater Flat Tuff) or intervening 

unnamed breccia, bedded turr, or ash-flow turr; underlies 

all constructional lavas of Wahmonie-Salyer volcanic center 

and rhyolite lavas or Calico Hills 

10. Type locality: Prow Pass, at N end or Yucca Mountain, Nye 

County, Nev. 

Pumpkinvine Creek Formation 

1. [Pennsylvanian or older, middle Paleozoic(?)] 

2. Georgia (NW) 

3. McConnell, K. I., 1980, Origin and correlation or the 

Pumpkinvine Creek Formation--a new unit in the Piedmont or 

northern Georgia: Georgia Geol-. Survey Inf. Circ. 52, 

p. 1-19 

4. Amphibolite, thin interlayers of gneiss and phyllite 

5. Gray 

6. <38 m 7. Fine-grained, interlayered, folded, easily traceable 

9. Structurally overlies informal Galts Ferry gneiss; 

135 
136 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

structurally underlies Canton Schist; sequence occupies 

overturned antiform 

Type locality: Exposures just SE of Pumpkinvine Creek along 

U.S. Highways I-75 and 41, SE Bartow County, Ga. 

Puncheon Camp Sandstone Member (Norton Formation) 

1. Middle Pennsylvanian 

2. Virginia (SW) 

3. Meissner, C. R., Jr., 1978, Geologic map of Duty quadrangle, 

Dickenson, Russell, and Buchanan Counties, Virginia: U.S. 

Geol. Survey Geol. Quad. Map GQ-1458 

4. Sands tone 

5. Gray 

6. Range 12-18 m 7. Fine- to coarse-grained, massive, forms ledges 

9. Overlies Puncheon Camp No. 1 coal bed; underlies Puncheon 

Camp No. 2 coal bed; lies above McClure Sandstone Member 

(Norton Formation) 

10. Type section: Along Long Ridge near town of Duty, Duty 

quadrangle, on border of Buchanan and Dickenson Counties, 

Va. 

Puritan Quartz Monzonite 

1. Precambrian, early [Late Archean] 

2. Michigan (NW) 

3. Schmidt, R. G., 1976, Geology of the Precambrian W (lower 

Precambrian) rocks in western Gogebic County, Michigan: 

U.S. Geol. Survey Bull. 1407, p. 14-18 

4. Quartz monzonite 

5. Pale-pinkish-gray 

7. Medium- to coarse-grained, coarsely porphyritic, intrusive 

igneous body 

9. Grades southward into Van Buskirk Gneiss within PuritanVan Buskirk pluton; intrudes Ramsay Formation and Whiskers 

Creek Gneiss; intruded by Sunset Creek Intrusive Complex; to 

N, underlies younger Precambrian strata 

10. Type locality: Exposures in SW1/4 sec. 17 and NW1/4 

sec. 20, T. 47 N., R. 46 W., close to site of old Puritan 

Mine, S of community of Puritan, Gogebic County, Mich. 

Pyramid Shale Member (Carrara Formation) 

1. Early and Middle Cambrian 

2. California (EC), Nevada 

3. Palmer, A. R., and Halley, R. B., 1979, Physical stratigraphy and trilobite biostratigraphy of the Carrara Formation 

(Lower and Middle Cambrian), southern Great Basin: U.S. 

Geol. Survey Prof. Paper 1047, p. 14-17 

4. Shale interbedded with siltstone, minor quartzite and 

limestone 

5. Green, brown, maroon 6. Range <1-172 m 

1. Fissile, slump folds, fossiliferous 

9. Overlies with sharp contact Gold Ace Limestone Member, or is 

inseparable from Echo Shale Member where Gold Ace is absent; 

conformably underlies Red Pass Limestone Member 

10. Type locality: Exposures at W base of Pyramid Peak, Funeral 

Mountains, Inyo County, Calif. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

P,aht Por.ation (Twin River Group) 

1. Oligocene, late, and Miocene, early (Zemorrian and 

Saucesian) 

2. Washington (NW) 

3. Snavely, P. D., Jr., Niem, A. R., and Pearl, J. E., 1978, 

Twin River Group (upper Eocene to lower Miocene)--defined to 

include the Hoko River, Makah, and Pysht Formations, Clallam 

County, Washington: U.S. Geol. Survey Bull. 1457-A, 

p. A118-A120 

4. Mudstone, sandy siltstone, with conglomerate and sandstone 

interbeds 

5. Gray to olive-gray 

6. Range 1,100-1,400 m 

7. Massive mudstone and siltstone; conglomerate and sandstone 

channels and lenses; calcareous concretions; fossiliferous 

9. Gradationally, or locally unconformably, overlies Makah 

Formation (Twin River Group); gradationally underlies 

Clallam Formation 

10. Type locality: Shore-cliff exposures along 18 km of Strait 

of Juan de Fuca from Pillar Point State Park, center sec. 10, T. 31 N., R. 11 W., E to point 3.5 km W of Low 

Point, SW1/4 sec. 19, T. 31 N., R. 9 W., Clallam County, 

Wash. Named for Pysht River, which flows into Strait of 

Juan de Fuca at Pillar Point. 

Quartzite Peak Quartzite (Libby Creek Group) 

1. Early Proterozoic 

2. Wyoming (SC) 

3. Divis, A. F., 1976, Geology and geochemistry of Sierra Madre 

Range, Wyoming: Colorado School Mines Quart., v. 71, no. 3, 

p. 27 

4. Orthoquartzite 

5. White 

6. >1,000 m 

7. Massive, unbedded, vitreous 

8. Lithologically similar to Sugarloaf Quartzite in Medicine 

Bow Range; conformably overlies Copper Creek Conglomerate; 

conformably underlies Slaughterhouse Marble 

137 

10. Type area: Exposures at Quartzite Peak and along North Fork 

of Encampment River, Sierra Madre Range, Carbon County, Wyo. 

Quassaic 

1. 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

Quartzite 

Middle Ordovician 

New York (SE) 

Fisher, D. W., 1977, Correlation of the Hadrynian, Cambrian 

and Ordovician Rocks in New York State: New York State Mus. 

Map and Chart Ser. 25, p. 60-61 

Quartzite and quartzitic sandstone with interbedded conglomerate, subgraywacke, and shale 

122 m, 610 m max Massive, molasse deposits derived from subaerially exposed 

allochthonous gravity slide units 

Conformably but sharply overlies Snake Hill Shale; uncon- formably underlies Wilbur Limestone 

Type locality: Along railroad, 1.6 km SW of Esopus, Ulster 

County, N.Y. 
138 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Ra.era canyon Tongue (Conejo Volcanics) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, 

Los Angeles County, California: U.S. Geol. Survey Bull. 

1457-E, p. E24 

4. Basaltic and andesitic breccia, tuff-breccia, flows(?) 

6. 518 m 

9. Lowest of three named tongues of Conejo Volcanics (Topanga 

Group), which are recognized only in upper plate of Malibu 

Bowl detachment fault. Overlies Topanga Canyon Formation 

(Topanga Group); underlies and interfingers with Escondido 

Canyon Shale and Dry Canyon Sandstone Members (Calabasas 

Formation) 

10. Type area: Ramera Canyon, Santa Monica Mountains, EC Point 

Dume quadrangle, Los Angeles County, Calif. 

Ramsay Foraation 

1. 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

Randall 

1-. 

2. 

3. 

4. 

5. 

9. 

10. 

Precambrian, early [Late Archean] 

Michigan (NW) 

Schmidt, R. G., 1976, Geology of the Precambrian W (lower 

Precambrian) rocks in western Gogebic County, Michigan: 

U.S. Geol. Survey Bull. 1407, p. 6-8 

Siliceous arkosic argillite, micaceous and arkosic metasiltstone, and metavolcanic tuff and breccia 

>300 m 

Thinly laminated, stratified, metamorphosed, schistose 

Grades into Whiskers Creek Gneiss close to Puritan Quartz 

Monzonite, which intrudes them; to N, unconformably underlies younger Precambrian strata 

Type locality: Outcrops extending S from edge of village of 

Ramsay along W side of Black River, SW1/4 sec. 13, NW1/4 

sec. 24 and within area 330 m S and W of NE corner sec. 23, 

all in T. 47 N., R. 46 W., Gogebic County, Mich. 

Formation (Mille Lacs Group) 

Precambrian, middle 

Minnesota (C) 

Morey, G. B., 1978, Lower and middle Precambrian. stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol. Survey Rept. Inv. 21, p. 21-23 

Metamorphosed basalt and diabase with lenses of cherty ironformation and quartzite 

Greenish-black, black 

Unconformably overlies and infolded with early Precambrian 

gneissic rocks, undivided; or overlies and underlies strata 

similar to Denham and Little Falls Formations, respectively, 

but assigned to Mille Lacs Group, undivided 

Type locality: Exposures in and near village of Randall, sec. 7, T. 130 N., R. 30 W., Morrison County, Minn. 

Rapson Creek Dolostone (Engadine Group) 

1. Middle Silurian (Niagaran) 

2. Michigan (EC) 

3. Johnson, A. M., and others, 1979, The Maple Block knoll reef 

in the Bush Bay Dolostone (Silurian, Engadine Group), 

Northern Peninsula of Michigan: Michigan Univ. Mus. Paleon-
4. 

5. 

6. 

7. 

9. 

10. 

Raspeburg 

1. 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

tology Papers on Paleontology, no. 20, p. 14 

Dolomite 

Light-gray to buff-gray, weathers mottled white-yellow 

21 m, range 21-27 m 

Massive, medium- to coarsely crystalline, organic reef, 

fossiliferous, banded 

Conformably overlies Rockview Dolostone; underlies Prentiss 

Creek Member (Bush Bay Dolostone) 

Type section: Cedarville quarry of U.S. Steel Corp., 

Mackinac County, Mich. Named for Rapson Creek, a stream NE 

of Cedarville. 

Amphibolite (Baltimore Mafic Complex) 

Cambrian(?) 

Maryland (NC) 

Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the 

eastern Maryland Piedmont: Maryland Geol. Survey Rept. 

Inv. 27, p. 16, 28 

Plagioclase-hornblende amphibolite 

Range <1-1,200 m 

Fine- to medium-grained 

Underlies Perry Hill Gneiss in NE-SW syncline; to NE, passes 

into Bradshaw Layered Amphibolite (Baltimore Mafic Complex); 

in thrust-fault contact with Wissahickon Group 

Type locality: Outcrops on Glenmount School property and 

abandoned quarry on W side of Bel Air Road, 400 m S of its 

intersection with Raspe Avenue, Raspeburg section of Baltimore City, Baltimore County, Md. 

Rattlesnake Hammock Formation (Ocean Reef Group) 

1. Early Cretaceous (Comanchean) 

2. Florida (SE) 

3. Winston, G. D., 1976, Six proposed formations in the 

undefined portion of the Lower Cretaceous section in south 

Florida: Gulf Coast Assoc. Geol. Socs. Trans., v. 26, p. 72 

4. Anhydrite, limestone, dolomite 

6. 225 m 

7. Thick, dense limestone at base; thick, regionally persistent 

anhydrite at top 

9. Overlies Lake Trafford Formation (Ocean Reef Group); underlies Marco Junction Formation (Big Cypress Group) 

10. Type section: Humble No. 1 Collier Corp. well, depthinterval 3,369-3,594 m, sec. 27, T. 50 S., R. 26 E., Collier 

County, Fla. Named for Rattlesnake Hammock, a natural 

feature 1.6 km N of type well. 

Rebecca Shoal Dolomite 

1. Late Cretaceous and Paleocene 

2. Florida (SE) 

3. Winston, G. 0., 1978, Rebecca Shoal reef-complex (Upper 

Cretaceous and Paleocene) in south Florida: Am. Assoc. 

Petroleum Geologists Bull., v. 62, no. 1, p. 121-127 

4. Anhedral dolomite 

5. Gray, tan, white 

6. 606 m 7. Subsurface, barrier-reef complex, fine-crystalline, numerous 

vugs, cavities, and caverns 

139 
140 

B. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Plantation Tongue and Tavernier Tongue 

Equivalent to and interfingers with Pine Key and Cedar Keys 

Formations 

Type section: Electric log of Gulf-California 1 OCS Block 

46 (permit 296), depth-interval 1,116-1,722 m, lat 24°26' 

N., long 82°30' W., Fla. Named for bathymetric feature, 11 

nautical miles N of type well, Straits of Florida. 

Red Hills Turr Member (Mount Belknap Volcanics) 

1. Miocene 

2. Utah (SC) 

3. Steven, T. A., and others, 1979, Revised stratigraphy and 

radiometric ages of volcanic rocks and mineral deposits in 

the Marysvale area, west-central Utah: U.S. Geol. Survey 

Bull. 1469, p. 26-27 

4. Ash-flow tuff 

5. Red, gray 

6. 300 m 

7. Simple cooling unit of densely welded ash-flow tuff derived 

from Red Hills caldera 

9. Overlies Joe Lott Tuff Member or intervening unnamed 

crystal-rich or upper red tuff members; underlies Gray Hills 

Rhyolite Member; units are part of outflow facies of Mount 

Belknap Volcanics 

10. Type area: Red Hills, about 4.8 km N 10° E of center of 

Marysvale, Piute County, Utah. 

Red Lick 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Member (Foreknobs Formation) 

Late Devonian 

West Virginia (C), Maryland, Virginia 

McGhee, G. R., Jr., and Dennison, J. M., 1976, The Red Lick 

Member, a new subdivision of the Foreknobs Formation (Upper 

Devonian) in Virginia, West Virginia, and Maryland: Southeastern Geology, v. 18, no. 1, p. 49-57 

Sandstone and siltstone with minor shale and conglomerate 

Light-olive-gray 

166 m, range <1-213 m Marine lagoonal deposit 

Conformably overlies Pound Sandstone Member (Foreknobs 

Formation); underlies Hampshire Formation 

Type section: Exposures along road beside Briery Gap Run, 

extending from U.S. Highway 33 toward Spruce Knob, Pendleton 

County, W. Va. Named for Red Lick Run, lat 38°4 1"1" N., 

long 79°29''52" W., 5.8 km SW of Briery Gap Run section. 

Red Mountain Subgroup (Chilliwack Group) 

1. Early Pennsylvanian 

2. Washington (NC), Canada (British Columbia) 

3. Danner, W. R., 1977, Paleozoic rocks of northwest Washington 

and adjacent parts of British Columbia, in Stewart, J. H., 

and others, eds., Paleozoic paleogeography of the western 

United States--Pacific Coast Paleogeography Symposium 1 

[Bakersfield, Calif., 1977]: Los Angeles, Soc. Econ. 

Paleontologists and Mineralogists, Pacific Sec., p. 489 

4. Argillite, siltstone, limestone 

6. Range 313-825 m 7. Turbidites and graded bedding in lower argillite-siltstone 

unit; fossiliferous upper limestone unit 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

9. Middle division of Chilliwack Group; overlies Sumas Mountain 

Subgroup; underlies Black Mountain Subgroup 

10. Type area: Quarry exposures on Red Mountain and Black 

Mountain, Whatcom County, Wash. 

Red Narrows Conglomerate 

1. Late Cretaceous and Paleocene 

2. Utah (C) 

3. Young, G. E., 1976, Geology of Billies Mountain quadrangle, 

Utah County, Utah: Brigham Young Univ. Geology Studies, 

v. 23, pt. 1, p. 220-226 

4. Conglomerate, sandstone, ~hale, limestone 

5. Red to reddish-brown 

6. 430 m 7. Massive, bedded 

8. Informal lower massive conglomerate unit; middle interbedded 

conglomerate--filled channels, sandstone, and shale unit; 

upper interbedded conglomerate, sandstone, shale, and lime--

stone unit 

9. Overlies Cretaceous conglomerate with angular unconformity; lies at surface or underlies and interfingers with Flagstaff 

Limestone 

10. Type section: Exposures extending from summit of Teat 

Mountain, NW1/4SW1/4SW1/4 sec. 15, T. 9 S., R. 5 E., along 

ridge crest on E side of Rough Hollow down to Red Narrows 

Canyon and U.S. Highway 50-6, NE1/4SW1/4NW1/4 sec. 33, 

T. 9 S., R. 5 E., Utah County, Utah. 

Red Pass Limestone Member (Carrara Formation) 

1. Middle Cambrian 

2. California (EC), Nevada 

3. Palmer, A. R., and Halley, R. B., 1979, Physical stratigraphy and trilobite biostratigraphy of the Carrara Formation 

(Lower and Middle Cambrian), southern Great Basin: U.S. 

Geol. Survey Prof. Paper 1047, p. 17-18 

4. Limestone, lime mudstone, oolite 

5. Light-gray, white 

6. Range <1-107 m 7. Cliff-forming, burrowed, oncolitic, fossiliferous 

9. Conformably overlies Pyramid Shale Member; underlies, with 

sharp contact, Pahrump Hills Shale Member 

10. Type locality: Exposures on W side of Titanothere Canyon 

below Thimble Peak, Grapevine Mountains, Inyo County, 

Calif. Named for Red Pass, 1 km E of Titanothere Canyon. 

Red Rock Ranch Formation 

1. Oligocene 

2. New Mexico (WC) 

3. Deal, E. G., and Rhodes, R. C., 1976, Volcano-tectonic 

structures in the San Mateo Mountains, Socorro County, New 

Mexico: New Mexico Geol. Soc. Spec. Pub. 5, p. 52 

4. Andesite flows with interbedded sedimentary rocks 

6. 1,000 m 7. Thin lacustrine interbeds contain plant fossils; source of 

eruption unknown, older than Nogal Canyon cauldron 

9. Unconformably overlies Paleozoic rocks; unconformably underlies Rock Spring Formation 

141 
142 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Type locality: Red Rock Ranch, S San Mateo Mountains, 

sec. 13, T. 10 S., R. 6 W., Sierra County, N. Mex. 

Redrock Valley Tuff 

1. Miocene 

2. Nevada (SC) 

3. Byers, F. M., Jr., and others, 1976, Volcanic suites and 

related cauldrons of Timber Mountain-Oasis Valley caldera 

complex, southern Nevada: U.S. Geol. Survey Prof. 

Paper 919, p. 7-10 

4. Ash-flow tuff 

5. Light-purplish-gray mottled with red 

6. 125 m, range 30-418 m 

7. Welded to nonwelded, has zonation of simple cooling unit 

9. Overlies Paleozoic rocks or Miocene unnamed .bedded tuff, 

which overlies Fraction Tuff; underlies, with local unconformity, unnamed bedded tuff, which underlies Bullfrog 

Member (Crater Flat Tuff) 

10. Type locality: Exposure on W side of Yucca Flat at hill 

5504, 2.4 km E of head of Redrock Valley, Tippipah Spring 

quadrangle, Nye County, Nev. 

Reformatory Granite 

1. Precambrian, middle 

2. Minnesota (C) 

3. Morey, G. B •. , 1978, Lower and middle Precambrian stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol. Survey Rept. Inv. 21, p. 38-40 

4. Granite containing inclusions of hornblende and biotite 

schist and dikes of granite porphyry and aplite 

5. Light- to dark-gray 

7. Massive, porphyritic; large, subsurface pluton 

9. Intruded by Stearns Granitic Complex 

10. Type locality: Abandoned quarries N of St. Cloud State 

Reformatory, SE1/4SW1/4 and SW1/4SE1/4 sec. 6, T. 35 N., 

R. 30 W., Sherburne County, Minn. 

Reinecker Ridge Volcanic Member (South Park Formation) 

1. Paleocene 

2. Colorado (C) 

3. Wyant, D. G., and Barker, Fred, 1976, Geologic map of the 

Milligan Lakes quadrangle, Park County, Colorado: U.S. 

Geol. Survey Geol. Quad. Map GQ-1343 

4. Hornblende andesite porphyry flows and breccias, lenticular 

porphyry-cobble conglomerate beds, and tuffaceous sandstone 

5. Brown, gray, green, or purple 

6. Range 150-305 m 7. Forms steep-sided ridges; weathers to distinctive pellets in 

lower part 

9. Overlies Laramie Formation; underlies unnamed conglomeratic 

member (South Park Formation) 

10. Type locality: Reinecker Ridge (formerly Basin Ridge) along 

aqueduct road, sec. 20, T. 9 S., R. 76 W., Como quadrangle, 

Park County, Colo. 

Reston Member (Manassas Sandstone) 

1. Late Triassic 

2. Virginia (NE), Maryland 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

3. Lee, K. Y., 1977, Triassic stratigraphy in the northern part 

of the Culpeper basin, Virginia and Maryland: U.S. Geol. 

Survey Bull. 1422-C, p. C3-C4 

4. Gravel; contains lenses of siltstone, sandstone, and 

conglomerate 

5. Pink to red-purple 

6. 5.5 m, range 5.5-22 m 

1. Loose to semicompact fluvial fan deposit, compact channelshaped lenses 

9. Unconformably overlies pre-Triassic mica schist; underlies 

and intertongues with unnamed sandstone member of Manassas 

Sandstone (Newark Group) 

10. Type section: Exposures E of entrance junction of S ramp of 

Dulles Airport Access Road with Reston Avenue, Reston, NW 

Vienna quadrangle, Fairfax County, Va. 

Richmond Gneiss 

1. Precambrian, early 

,2. Minnesota (C) 

3. Morey, G. B., 1978, Lower and middle Precambrian stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol. Survey Rept. Inv. 21, p. 7-9 

4. Feldspar-quartz-hypersthene-hornblende gneiss with porphyroblasts of K-feldspar and lenses of biotite schist and 

amphibolite 

5. Black to grayish-black, oxidizes reddish gray to pale red 

7. Vaguely foliated 

9. Intruded on E by Stearns Granite Complex; unconformably 

underlies Cretaceous sedimentary rocks to W and S 

10. Type locality reported by Morey (1978) is incorrect. 

Corrected type locality: SW1/4SW1/4 sec. 20, and NW1/4NW1/4 

sec. 29, T. 123 N., R. 30 W., Wakefield Township, Stearns 

County, Minn. (Dacre, G. A., Himmelberg, G. R., and Morey, 

G. B., 1984, Pre-Penokean igneous and metamorphic rocks, 

Benton and Stearns Counties, central Minnesota: Minnesota 

Geol. Survey Rept. of Inv. no. 31, p. 3.) Named for exposures along Sauk River valley near town of Richmond. 

Ridgeland Formation (Lake Bonneville Group) 

1. Holocene 

2. Utah (NC) 

3. Van Horn, Richard, 1979, The Holocene Ridgeland Formation 

and associated Decker Soil (new names) near Great Salt Lake, 

Utah: U.S. Geol. Survey Bull. 1457-C, p. C1-C11 

4. Silt, clay 

5. Gray to dark-brown 

6. 0.51 m, range 0.15-1.90 m 7. Massive, calcareous, tastes slightly salty, fossiliferous 

9. Unconformably overlies Midvale Soil, which is formed on 

Draper Formation (Lake Bonneville Group); grades into over- lying Decker Soil (formed on Ridgeland Formation), which 

lies at surface 

10. Type section: Exposures in W bank of Ridgeland Canal, 

SW1/4SE1/4 sec. 20, T. 1 S., R. 1 W., Salt Lake City South 

quadrangle, Salt Lake County, Utah. Named for Ridgeland 

Canal. 

143 
144 

Ridgepole 

1. 

2. 

3. 

4. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Mountain Formation (Coweeta Group) 

Precambrian, late(?) [Late Proterozoic(?)] 

North Carolina (WC), Georgia 

Hatcher, R. D., Jr., 1979, The Coweeta Group and Coweeta 

syncline--major features of the North Carolina-Georgia Blue 

Ridge: Southeastern Geology, v. 21, no. 1, p. 23 

Biotite-garnet schist and quartzite, interlayered with 

pelitic schist and garnetiferous metasandstone 

Overlies Coleman River Formation (Coweeta Group); upper 

contact not observed (top eroded) 

Type area: Exposures on Ridgepole Mountain and Little 

Ridgepole Mountain, Prentiss quadrangle, Macon County, N.C. 

Riggins 

1. 

2. 

3. 

Mill Member (Clinchfield Formation) 

Eocene, late 

4. 

5. 

6. 

7. 

9. 

10. 

Georgia (C) 

Huddlestun, P. F., and Hetrick, J. H., 1979, The stratigraphy of the Barnwell Group of Georgia: Georgia Geol. 

Survey Open File Rept. 80-1, p. 11-12, 78-80 

Sand, limestone 

Grayish-yellow to pale-yellow 

4.1 m, range <1-5.2 m 

Unconsolidated, concretionary, fossiliferous 

Overlies Huber Formation; gradationally underlies Treadwell 

Member (Clinchfield Formation); grades laterally into 

undivided weathered and leached Clinchfield Formation 

Type locality: Georgia Kaolin Co. Pit 50, 1.2 km SW of 

Riggins Mill Road and community of Treadwell, 2.24 km SE of 

Bibb Twiggs County line, Twiggs County, Ga. 

Rio Abajo For.ation 

1. Early(?) Cretaceous 

2. Puerto Rico (EC) 

3. M'Gonigle, J. W., 1977, The R{o Abajo, Pitahaya, and Daguao 

Formations in eastern Puerto Rico: U.S. Geol. Survey Bull. 

1435-B, p. B4-B6 

4. Andesitic volcaniclastic tuff, breccia, conglomerate, and 

lava flows 

5. Medium-gray to brownish-gray, speckled 

6. >600 m 

7. Coarse- to fine-grained crystal and crystal-lithic tuff, 

massive to medium-bedded and graded 

9. Base and top not exposed; in fault contact with Pitahaya 

Formation and informal Late Cretaceous Mambiche sequence; 

may unconformably underlie Pitahaya Formation to W of study 

area 

10. Type area: Exposures in roadcuts and quarry along Highway 

924 between 37,500 to 38,200 N. and 217,900 E. and in small 

borrow pit along Route 3 at 35,500 N., and 222,300 E., near R{o Abajo, Humacao quadrangle, P.R. 

River Bend Formation 

1. Oligocene, middle and late 

2. North Carolina (EC) 

3. Ward, L. W., Lawrence, D. R., and Blackwelder, B. W., 1978, 

Stratigraphic revision of the middle Eocene, Oligocene, and 

lower Miocene--Atlantic Coastal Plain of North Carolina: 

U.S. Geol. Survey Bull. 1457-F, p. F10-F13 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

4. Limestone, including biocalcarenite, biocalcirudite, and 

shell hash 

5. Light- to medium-gray, grayish-orange 

6. 3 m, range 3-150 m 

7. Arenaceous, fossiliferous, molluscan molds 

9. Unconformably overlies Castle Hayne Formation; unconformably 

underlies Belgrade Formation or Duplin Formation 

10. Type locality: Exposures 0.3 km above Rhems Landing, L bank 

of Trent River, just below River Bend, Craven County, N.C. 

Riverdale Member (Oahe Formation) 

1. Holocene 

2. North Dakota (C) 

3. Clayton, Lee, Moran, S. R., and Bickley, W. B., Jr., 1976, 

Stratigraphy, origin, and climatic implications of late 

Quaternary Upland silt in North Dakota: North Dakota Geol. 

Survey Misc. Ser., no. 54, p. 6-7 

4. Silt, clay, and sand 

5. Grayish-brown, brownish-gray 

6. 1.1 m B. Three informal submembers 

9. Overlies Pick City Member; lies at surface 

10. Type section: Riverdale Section, bluffs of Lake Sakakawea, 

center sec. 22, T. 147 N., R. 84 W., McLean County, 

N. Oak. Named for town of Riverdale, 4 km S of Riverdale 

Section. 

Rock Knoll Formation (Deep Lake Group) 

1. Early Proterozoic 

2. Wyoming (SE) 

3. Karlstrom, K. E., and Houston, R. S., 1979, Stratigraphy and 

uranium potential of Early Proterozoic metasedimentary rocks 

in the Medicine Bow Mountains, Wyoming: Wyoming Geol. 

Survey Rept. Inv. 13, p. 21, 44-45 

4. Quartzite interbedded with phyllite and conglomerate 

5. Gray 

6. 303 m 

7. Quartzite, fine-grained; ripple marks and tabular cross- bedding; probably shallow-marine deposits 

9. Overlies Vagner Formation (Deep Lake Group); underlies Headquarters Formation (Libby Creek Group) 

10. Type section: SE face of Rock Creek Knoll, sec.35, T. 17 N., 

R. 79 W., Medicine Bow Mountains, Carbon County, Wyo. 

Rock Spring Formation 

1. Oligocene 

2. New Mexico (WC) 

3. Deal, E. G., and Rhodes, R. C., 1976, Volcano-tectonic 

structures in the San Mateo Mountains, Socorro County, New 

Mexico: New Mexico Geol. Soc. Spec. Pub. 5, p. 52 

4. Andesite and latite tuff, lava, breccia 

6. Range 200-1,000 m 

7. Source of eruption unknown, older than Nogal Canyon cauldron 

9. Unconformably overlies Red Rock Ranch Formation; underlies 

Vicks Peak Rhyolite 

10. Type locality: Rock Spring, S San Mateo Mountains, sees. 13, 14, and 26, T. 9 s., R. 6 W., Socorro County, N. Mex. 

145 
146 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Rockview Dolostone (Engadine Group) 

1. Middle Silurian (Niagaran) 

2. Michigan (EC) 

3. Johnson, A. M., and others, 1979, The Maple Block knoll reef 

in the Bush Bay Dolostone (Silurian, Engadine Group), 

Northern Peninsula of Michigan: Michigan Univ. Mus. Paleontology Papers on Paleontology, no. 20, p. 14 

4. Dolomite 

5. Gray to bluish-gray, weathers white 

6. Range 8-14 m 

7. Massive, medium- to coarsely crystalline, algal reef, 

fossiliferous 

9. Conformably(?) overlies Cordell Dolostone (Manistique 

Group); conformably underlies Rapson Creek Dolostone 

(Engadine Group) 

10. Type locality: Rural community of Rockview, sec. 25, 

T. 43 N., R. 1 W., Mackinac County, and sec. 30, T. 43 N., 

R. 1 E., Chippewa County, Mich. 

Ronald Member (Lakedale Drift) 

1. Pleistocene 

2. Washington (C) 

3. Porter, S. C., 1976, Pleistocene glaciation in the southern 

part of the North Cascade Range, Washington: Geol. Soc. 

America Bull. , v. 87, no. 1 , p •. 70 

4. Till, gravel, sand, silt 

7. Moraine, outwash; mantled by loess 

8. Till and outwash facies 

9. Overlies Bullfrog Member; underlies Domerie Member 

10. Type locality: Till facies: cut along S bank of Yakima 

River, E of U.S. Highway I-90, SE1/4NW1/4 sec. 36, T. 20 N., 

R. 14 E.; outwash facies: cut along N bank of Yakima River 

in riser of Ronald terrace, SE1/4SE1/4 sec. 28, T. 20 N., 

Rookery 

1. 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

R. 15 E., Kittitas County, Wash. Named for nearby town of 

Ronald. 

Bay Formation (Naples Bay Group) 

Early Cretaceous (Comanchean) 

Florida (SE) 

Winston, G. D., 1976, Six proposed formations in the 

undefined portion of the Lower Cretaceous section in south 

Florida: Gulf Coast Assoc. Geol. Socs. Trans., v. 26, 

p. 70-:-71 

Anhydrite with interbedded chalky limestone and dolomite 

147 m 

Thin pelletal micritic limestone at base; thick, regionally 

persistent anhydrite bed at top 

Overlies Panther Camp Formation; underlies Corkscrew Swamp 

Formation 

Type section: Humble No. 1 Collier Corp. well, depthinterval 2,760-2,907 m, sec. 27, T. 50S., R. 26 E., Collier 

County, Fla. Named for Rookery Bay along W coast of 

Florida, 8 km SW of type well. 

Roosevelt Gabbros (Raggedy Mountain Gabbro Group) 

1. Cambrian 

2. Oklahoma (C) 

3. Powell, B. N., Gilbert, M. c., and Fischer, J. F., 1980, 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Lithostratigraphic classification of basement rocks of the 

Wichita province, Oklahoma: Summary: Geol. Soc. America 

Bull., pt. 1, v. 91, no. 9, p. 510-513 

4. Biotite-amphibole-olivine gabbro, biotite-amphibole-two 

pyroxene-gabbro and biotite-gabbro 

1. Medium-grained, forms dikes, sills, irregu~r bodies 

8. Glen Creek Gabbro, Sandy Creek Gabbro, Mount Sheridan Gabbro 

9. Intrusive into Glen Mountains Layered Complex (Raggedy 

Mountain Gabbro Group); intruded by Mount Scott Granite 

10. Type area: Tps. 3 and 4 N., Rs. 13, 15, 17 W., Glen and 

Wichita Comanche and Kiowa.Counties, Okla. Named for town 

of Roosevelt, sec. 6, T. 4 N., R. 17 W., Kiowa County. 

Rope Ferry Gneiss (Waterford Group) 

1. Late Proterozoic 

2. Connecticut (SE) 

3. Goldsmith, Richard, 1980, Stratigraphic names in the New 

London area, southeastern Connecticut--a revision: U.S. 

Geol. Survey Bull. 1502-A, p. A96-A99 

4. Hornblende-biotite-quartz-plagioclase gneiss 

5. Gray 

6. 1 , 130 m max 

1. Lenticularly layered, locally massive 

9. Overlies New London Gneiss (Waterford Group); unconformably 

underlies schist in Hunts Brook with sharp contact 

10. Type area: Exposures between Rope Ferry Road and Jordan 

Cove in town of Waterford, New London County, Conn. 

Rosarito 

1. 

2. 

3. 

4. 

6. 

8. 

9. 

10. 

Beach Formation 

Miocene and Pliocene 

Mexico (NW), California 

Minch, J. A., 1967, Stratigraphy and structure of the 

Tijuana-Rosarito Beach area, northwestern Baja California, 

Mexico: Geol. Soc. America Bull., v. 78, no. 9, p. 1158-

1165 

Basalt flows and interbedded sandstone, siltstone, mudstone, 

and bentonitic claystone 

360 m Subdivided in Mexico into western block with Mira al Mar and 

Costa Azul Members, and eastern block with Amado Nervo, Las 

Glorias, and Los Buenos Members. Not subdivided in 

California 

Overlies Eocene rocks or Sweetwater Formation; unconformably 

underlies San Diego Formation; upper part equivalent to Otay 

Formation 

Type section: Designated for each member in TijuanaRosarito Beach area, NW Baja California, Mex.; 0.8 km S of 

Rancho Miro al Mar; 91 m E of Rancho Jose; 2.8 km S of 

Escuela Amado Nervo; 2 km SW of town of La Gloria; and W of 

Escuela Los Buenos, Mexico. 

Rottenwood Creek Quartzite (Sandy Springs Group) 

1. Precambrian, late(?), and (or) Paleozoic, early(?) 

2. Georgia (NW) 

3. Higgins, M. W., and McConnell, K. I., 1978, The Sandy 

Springs Group and related rocks in the Georgia Piedmont--

nomenclature and stratigraphy: U.S. Geol. Survey Bull. 

1457-A, p. A104 (Also published in: Georgia Geol. Survey 

147 
148 

4. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Bull. 93, p. 53, 1978) 

Muscovite-bearing quartzite 

50 m 

Massive, crops out along axial traces of synforms and is 

absent in many places owing to erosion or nondeposition(?) 

Gradationally overlies Factory Shoals Formation; uppermost 

unit of Sandy Springs Group 

Type area: Exposures along Rottenwood Creek 1000 m SE of 

Akers Mill Road, Sandy Springs quadrangle, Fulton County, 

Ga. 

Roxboro 

1 • 

2. 

3. 

Metagranite 

Precambrian, late, to Early Cambrian 

North Carolina (NC) 

Briggs, D. F., Gilbert, M. c., and Glover, Lynn, III, 1978, 

Petrology and regional significance of the Roxboro Metagranite, North Carolina: Geol. Soc. America Bull., v. 89, no. 4, p. 511-521 

4. 

5. 

7. 

9. 

10. 

Granite, alkali-feldspar granite, and granodiorite facies 

with phenocrysts of plagioclase, quartz, and perthite 

Light- to medium-gray 

Microphaneritic 

Intrudes late Precambrian and Early Cambrian(?) volcanic and 

epiclastic rocks 

Type area: Roxboro quadrangle, Person County, N.C. 

Ruff Formation (Salina Group) 

1. Late Silurian 

2. Michigan (SE) 

3. Budros, Ron, and Briggs, L. I., 1977, Depositional environment of Ruff Formation (Upper Silurian) in southeastern 

Michigan: Am. Assoc. Petroleum Geologists Studies in 

Geology, no. 5, p. 53-71 

4. Calcitic to dolomitic mudstone, anhydrite 

5. Brown to dark-grayish-brown, white anhydrite 

7. Foreslope shelf deposits 

8. Informal lithofacies A through E: microlaminated mudstone, 

leached mudstone, pelletal wackestone-packstone, thinly 

laminated mudstone, nodular anhydrite 

9. Overlies informal A-1 evaporite unit of Salina Group; underlies A-2 evaporite unit. Former informal A-1 carbonate unit 

10. Type section: Consumers Power Co., 1-36 Ruff well, 

SE1/4SW1/4NE1/4 sec. 36, T. 5 N., R. 16 E., St. Clair 

County, Mich. 

Rumsey Formation 

1. Late Cretaceous 

2. California (NW) 

3. Ingersoll, R. V., Rich, E. I., and Dickinson, W. R., 1977, 

Field guide--Great Valley Sequence, Sacramento Valley: 

Geol. Soc. America, Cordilleran Sec., Ann. Mtg., [Guidebook 

8J, p. 28, 34-36 

4. Concretionary sandstone, siltstone, shale 

5. Gray 

6. 915 m, range 365-1,220 m 

7. Massive to well-bedded, fine- to medium-grained sandstone; 

laminated siltstone; felsic plutonic detritus deposited in 

deep-marine trough 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

8. Guinda Sandstone Member at base 

9. Overlies Cortina Formation; unconformably underlies Tertiary or Quaternary rocks 

10. Type section: Exposures along Petroleum Creek and Salt 

Creek, T. 12 N., R. 3 W., N end of Rumsey Hills, Rumsey 

quadrangle, Yolo County, Calif. 

Rush Brook Member (Loch Raven Schist) 

1 • 

2. 

3. 

4. 

6. 

1, 

9. 

10. 

Rushmere 

1. 

2. 

3. 

4. 

5. 

6. 

1. 

9. 

10. 

Cambrian-Ordovician(?) 

Maryland (NC) 

Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the eastern Maryland Piedmont: Maryland Geol. Survey Rept. Inv. 27, 

p. 10-11, 23-24 

Interlayered biotite-feldspar-quartz gneiss, biotitefeldspar-quartz schist, muscovite-biotite-feldspar-quartz 

schist 

Range <1-600 m 

Fine-grained 

Overlies Cockeysville Marble; underlies main body of Loch 

Raven Schist as discontinuous basal unit 

Type locality: Outcrops along Rush Brook, tributary of Loch 

Raven Reservoir, from Loch Raven Road S for 155 m, Baltimore 

County, Md. 

Member (Yorktown Formation) 

Pliocene, early 

Virginia (SE), North Carolina 

Ward, L. W., and Blackwelder, B. W., 1980, Stratigraphic 

revision of upper Miocene and lower Pliocene beds of the 

Chesapeake Group, Middle Atlantic Coastal Plain: U.S. Geol. 

Survey Bull. 1482-D, p. D36-D40 

Shelly sand, sandy clay 

Blue-gray 

1.1 m Well-sorted, fine-grained 

Conformably overlies Sunken Meadow Member; conformably 

underlies Morgarts Beach Member 

Type locality: Exposures 0.7 km E of Rushmere, R bank of 

James River, Isle of Wight County, Va. Named for beds at 

Burwell Bay near Rushmere. 

Sabot Amphibolite 

1. Precambrian, late, and (or) Early Cambrian 

2. Virginia (EC) 

3. Poland, F. B., Glover, Lynn, III, and Mose, D. G., 1979, The 

geology of the rocks along the James River between Sabot and 

Cedar Point, Virginia, in Glover, Lynn, III, and Tucker, 

R. D., eds., Virginia Piedmont geology along the James River 

from Richmond to the Blue Ridge--Field trip 1, of Guides to 

field trips 1-3: Blacksburg, Va., Geol. Soc. America, 

Southeastern Sec., p. 11 

4. Amphibolite intercalated with biotite gneiss 

1. Massive, homogeneous; flanks NNE-trending antiform occupied 

by State Farm Gneiss 

9. Structurally overlies State Farm Gneiss; structurally underlies Maidens Gneiss 

10. Type area: Exposures along James River at village of Sabot 

149 
150 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

and midway between Sabot and Cedar Point, Goochland County, 

Va. 

Saddle Peak Member (Topanga Canyon Formation) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E16 

4. Sandstone, sandy siltstone, basal conglomerate 

6. 220 m 

7. Sandstone, thick-bedded to massive, medium- to coarsegrained, pebbly, fossiliferous 

9. Conformably overlies Piuma Member (Sespe Formation); conformably underlies Fernwood Member (Topanga Canyon 

Formation) 

10. Type locality: Roadcuts along Piuma Road, NE1/4 sec. 21, 

T. 1 S., R. 17 W., SW of Saddle Peak, Santa Monica 

Mountains, Malibu Beach quadrangle, Los Angeles County, 

Calif. 

Sandy Formation (Packsaddle Group) 

1. Precambrian 

2. Texas (C) 

3. McGehee, R. V., 1979, Precambrian rocks of the southeastern 

Llano region, Texas: Texas, Univ., Austin, Bur. Econ. Geology Geol. Circ. 79-3, p. 9-10 

4. Leptite, hornblende schist 

5. Light-gray, light-pink 

6. 700 m 

9. Overlies Honey Formation; underlies Rough Ridge Formation. 

Unit was formerly Honey Creek Member (Packsaddle Formation) 

of McGehee (1964) 

10. Type section: Along Sandy Creek, from near State Highway 71 

bridge, Dunman Mountain quadrangle, to near mouth of Cottonwood Creek, Click quadrangle, Llano County, Tex. 

Sandy Creek Gabbro (Roosevelt Gabbros) 

1. Cambrian 

2. Oklahoma (C) 

3. Powell, B. N., Gilbert, M. C., and Fischer, J. F., 1980, 

Lithostratigraphic classification of basement rocks of the 

Wichita province, Oklahoma: Summary: Geol. Soc. America 

Bull., pt. 1, v. 91, no. 9, p. 510-513 

4. Biotite-amphibole-two-pyroxene gabbro, ranging from olivineto quartz-rich gabbro 

7. Irregular intrusive body 

9. Intrusive into Glen Mountains Layered Complex (Raggedy Mountain Gabbro Group); intruded by Mount Scott Granite 

10. Type locality: Outcrops near Sandy Creek, NE1/4NW1/4 and 

NW1/4NE1/4 sec. 9, T. 3 N., R. 15 W., Wichita Mountains, 

Comanche County, Okla. 

Sandy PoDd Amphibolite Meaber (Marlboro Formation) 

1. pre-Silurian 

2. Massachusetts (C) 

3. Bell, K. G., and Alvord, D. C., 1976, Pre-Silurian stratig-
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

raphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 188-189, 205-206, app. 1 (in pocket) 

4. Complexly interstratified hornblende amphibolite and actinolitic amphibolite, minor gneiss and schist lenses 

5. Dark-greenish-gray 

6. 640 m 

7. Fine- to coarse-grained, thin-bedded and massive 

9. Overlies unnamed lower member of Marlboro Formation; underlies Shawsheen Gneiss 

10. Type locality: NE-trending rocky ridges at S and E sides of 

Sandy Pond, Concord quadrangle, Middlesex County, Mass. 

Sandy Springs Group 

1. Precambrian, late(?), and (or) Paleozoic, early(?) 

2. Georgia (NW) 

3. Higgins, M. W., and McConnell, K. I., 1978, The Sandy 

Springs Group and related rocks in the Georgia Piedmont--

nomenclature and stratigraphy: U.S. Geol. Survey Bull. 

1457-A, p. A98-A101 (Also published in: Georgia Geol. 

Survey Bull. 93, p. 50-53, 1978) 

4. Gneiss, schist, quartzite, amphibolite 

6. >3,000 m 

7. Linear NE-trending ridges generally underlain by quartzite, 

and valleys and slopes underlain by gneiss, schist, and 

amphibolite 

8. Powers Ferry Formation, with its Mableton Amphibolite 

Member, Chattahoochee Palisades Quartzite, Factory Shoals 

Formation, Rottenwood Creek Quartzite 

9. Base of group not exposed; in fault contact, for long 

distances along its SE boundary, with Long Island Creek 

Gneiss and Yellow Dirt Gneiss 

10. Type area: Town of Sandy Springs, Sandy Springs quadrangle, 

Fulton County, Ga. 

San Nicholas Member (Vaqueros Formation) 

1. Miocene, early 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E12-E13 

4. Sandstone 

5. Light-gray to bluish-gray 

6. 150 m 7. Thick-bedded to massive, cliff-forming, fossiliferous 

9. Conformably overlies Danielson Member (Vaqueros Formation); 

conformably underlies Encinal Member (Topanga Canyon 

Formation) 

10. Type locality: Exposures in San Nicholas Canyon, Santa 

Monica Mountains, EC Triunfo Pass quadrangle, Los Angeles 

County, Calif. 

Santas Pascuas Member (Lago Garzas Formation) 

1. Late Cretaceous (Campanian(?) and Maestrichtian) 

2. Puerto Rico (SC) 

3. Krushensky, R. D., and Monroe, W. H., 1978, Geologic map of 

the Peftuelas and Punta Cuchara quadrangles, Puerto Rico: 

U.S. Geol. Survey Misc. Inv. Ser. Map I-1042 

151 
152 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Pumiceous lapilli tuff, vitric and vitric crystal tuff, 

porphyritic lava, and limestone 

Light-bluish-green, light-medium-green, and pale-yellowishbrown 

>350 m Deeply saprolitized 

Overlies and interbedded with Pastillo Member (Lago Garzas 

Formation); unconformably underlies Tertiary rocks 

Type area: From first E-flowing unnamed tributary on R!o 

Caffas, 1.3 km N of Hacienda Batiz, to village of Santas 

Pascuas, on N border of Penuelas quadrangle, P.R. 

Santiago Canyon Tu~~ 

1. Oligocene, late, or Miocene, early 

2. Nevada (WC) 

3. Bingler, E. C., 1978, Abandonment of the name Hartford Hill 

Rhyolite Tuff and adoption of new formation names for middle 

Tertiary ash-flow tuffs in the Carson City-Silver City area, 

Nevada: U.S. Geol. Survey Bull. 1457-D, p. D17-D19 

4. Hornblende-biotite quartz latite tuff 

5. Gray-white to gray 

6. >300 m 

7. Crystal-vitric, weakly welded to glassy, densely welded 

vitrophyre; simple cooling unit 

9. Disconformably overlies older Tertiary tuffs or unconformably overlies Mesozoic rocks; unconformably underlies Alta 

Formation 

10. Type section: Exposures at mouth of Santiago Canyon, NW1/4 

sec. 5, T. 15 N., R. 21 E., New Empire quadrangle, Carson 

City, Nev. 

Sartell 

1. 

2. 

3. 

4. 

5. 

7. 

9. 

10. 

Gneiss (Sauk Rapids Metamorphic Complex) 

Precambrian, early 

Minnesota (C) 

Morey, G. B., 1978, Lower and middle Precambrian stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol. Survey Rept. Inv. 21, p. 9-10 

Interlayered quartzofeldspathic gneiss and garnet- and 

cordierite-bearing biotite gneiss 

Pinkish-gray and brownish-gray 

Well-foliated to massive 

Encloses lenticular bodies of St. Wendel Metagabbro (Sauk 

Rapids Metamorphic Complex); interlayered to SE with Watab 

Amphibolite (Sauk Rapids Metamorphic Complex); truncated on SE by intrusive Stearns Granitic Complex; unconformably 

underlies Cretaceous sedimentary rocks to W and S 

Type locality: Outcrops N of village of Sartell on E side 

of Mississippi River, SW1/4 sec. 4, T. 36 N., R. 30 W., 

Benton County, Minn. 

Sauk Rapids Metamorphic Complex 

1. Precambrian, early 

2. Minnesota (C) 

3. Morey, G. B., 1978, Lower and middle Precambrian stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol. Survey Rept. Inv. 21, p. 9-11 

4. Gneiss, amphibolite, metagabbro 

7. Antiforms and synforms with moderate-dipping limbs and 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

shallow E-plunging axes 

8. Sartell Gneiss, Watab Amphibolite, St. Wendel Metagabbro 

10. Type area: Exposures on both sides of Mississippi River N 

of St. Cloud in St. Wendel and Le Sauk Townships, Stearns 

County, and in Sauk Rapids and Watab Townships, Benton 

County, Minn. Named for city of·Sauk Rapids. 

Sausbee For.ation 

1. Early Pennsylvanian (Morrowan) 

2. Oklahoma (EC) 

3. Sutherland, P. K., and Henri, T. W., 1977, Carbonate 

platform facies and new stratigraphic nomenclature of the 

Morrowan Series (Lower and Middle Pennsylvanian), 

northeastern Oklahoma: Gaol. Soc. America Bull., v. 88, no. 3, p. 429-432 

4. Limestone interbedded with shale and, in lower part, sandstone and basal conglomerate 

6. 33.5 m, range 15.5-61 m 

8. Braggs Member, Brewer Bend Limestone Member 

9. Unconformably overlies Pitkin Limestone; unconformably 

underlies McCully Formation 

10. Type section: Measured Section 1, W bluff of Arkansas 

River, 9-183 m S from W end of Webbers Falls Lock and Dam, 

SW1/4SW1/4SE1/4 sec. 34, T. 13 N., R. 20 E., and Measured 

Section 3, 0.5 km NW of MS 1 along river bluff, 

S1/2NW1/4SW1/4 sec. 34, T. 13 N., R. 20 E., Muskogee County, 

Okla. Derivatiop of name not stated. 

Sciota Limestone Member (Fort Cassin Formation) 

1. Early Ordovician 

2. New York (NE) 

3. Fisher, D. W., 1977, Correlation of the Hadrynian, Cambrian 

and Ordovician rocks in New York State: New York State Mus. 

Map and Chart Ser., no. 25, p. 62 

4. Dolomitic limestone 

5. Gray 

6. Range <1-35 m 

7. Medium- to thick-bedded, fine- to coarse-grained, fossiliferous 

9. Transitionally overlies Ward Siltstone Member; transitionally underlies Providence Island Dolostone Member 

10. Type locality: Near abandoned Sciota School, on Washington 

County Route 10, 8.5 km NNE of intersection of U.S. Highway 

4 and New York Highway 22 in Whitehall, Thorn Hill quadrangle, Washington County, N.Y. 

Scotts Hill Member (Peedee Formation) 

1. Late Cretaceous 

2. North Carolina (SE), South Carolina 

3. Ward, L. W., and Blackwelder, B. W., 1979, Scotts Hill 

Member (new name) of the Cretaceous Peedee Formation of 

southeasternmost North Carolina and east-central South 

Carolina: U.S. Geol. Survey Bull. 1482-A, p. A87-A88 

4. Sandy pelecypod biosparrudite, quartz arenite 

6. Range <1-27 m 

9. Unconformably underlies Castle Hayne Formation; upper 

contact is Cretaceous-Tertiary boundary 

10. Type area: Outcrops only along NE Cape Fear River near town 

153 
154 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

of Scotts Hill, New Hanover County, N.C. Present in 

subsurface of adjoining counties, including Pender County. 

Sedan Fo~ation (Livingston Group) 

1. Late Cretaceous 

2. Montana (SC) 

3. Skipp, Betty, and McGrew, L. W., 1977, The Maudlow and Sedan 

Formations of the Upper Cretaceous Livingston Group on the 

west edge of the Crazy Mountains basin, Montana: U.S. Geol. 

Survey Bull. 1422-B, p. B3-B20 

4. Sandstone, mudstone, conglomerate, interbedded with mudflow 

conglomerate and tuff 

5. Gray 

6. 1,076 m, range 915-1,372 m 7. Nonmarine epiclastic volcanic sediments 

8. Lower sandstone, welded tuff, middle sandstone, and mudstone 

members, Bearpaw Shale Member, Lennep Sandstone Member 

9. Disconformably to gradationally overlies Eagle Sandstone; 

conformably underlies Billman Creek Formation (Livingston 

Group) 

10. Type section: Sees. 6, 1, 17, and 18, T. 4 N., R. 8 E., SE 

corner Sixteen NE quadrangle and NE corner Wallrock quadrangle, Park County, Mont. Named for hamlet of Sedan on E 

flank of Bridger Range. 

Sedgefield Member (Tabb Formation) 

1. Pleistocene, late 

2. Virginia (SE) 

3. Johnson, G. H., 1976, Geology of the Mulberry Island, 

Newport News North, and Hampton quadrangles, Virginia: 

Virginia Div. Mineral Resources Rept. Inv. 41, p. 33-35 

4. Clayey and gravelly sand, clay 

5. Gray, tan to yellowish-brown, bluish-gray 

6. 3.5 m, range 1-3.5 m 

7. Brackish-bay, lagoonal marsh, and nearshore marine deposits; 

basal fossiliferous, cobbly, clayey, medium to coarse sand 

9. Unconformably overlies Yorktown Formation or Norfolk 

Formation; unconformably underlies Lynnhaven Member (Tabb 

Formation) 

10. Type section: Exposure in Williams Paving Co. sand pit, 0.6 

km W of Big Bethel Road (State Road 600) and 1.1 km N of 

U.S. Highway I-64, City of Hampton, Va. Named for settlement of Sedgefield, city of Newport News. 

Seward Member (Duperow Formation) 

1. Late Devonian 

2. Canada (Saskatchewan), Montana 

3. Kent, D. M., 1963, The stratigraphy of the Upper Devonian 

Saskatchewan Group of southwestern Saskatchwan: Saskatchewan Dept. Mineral Resources Rept. 73, p. 21-24 

4. Argillaceous limestone, dolomite, shale, and evaporites 

5. Varicolored 

6. 69 m 1. Fossiliferous, subsurface 

9. Conformably overlies Wymark Member (Duperow Formation); 

conformably underlies Birdbear Formation 

10. Type section: Mobil Oil Woodley Sinclair Cantuar No. X-2-21 

well, depth-interval 1,391-1,460 m, Lsd. 2-21-16-17W3, 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 155 

Saskatchewan, Canada. Named for Seward Forest Reserve, 8 km 

S of type well. 

Sbavsheen Gneiss 

1. pre-Silurian 

2. Massachusetts (C) 

3. Bell, K. G., and Alvord, D. C., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 188-189, 206-207, app. 1 (in pocket) 

4. Muscovite-biotite-oligoclase-quartz gneiss with lenticular 

bodies of amphibolite 

5. Medium-gray 

6. 2, 600 m 

7. Medium-grained, ripple-bedded, relict sedimentary structures 

9. Overlies Marlboro Formation; underlies Fish Brook Gneiss 

10. Type locality: Belt along NW side of Shawsheen River, 

Billerica and Wilmington quadrangles, and in Harold Parker 

State Forest, Reading quadrangle, Middlesex County, Mass. 

Sbellaodnd For.ation 

1. Late Ordovician 

2. Tennessee (SC), Georgia 

3. Milici, R. C., and Wedow, Helmuth, Jr., 1977, Upper Ordovician and Silurian stratigraphy in Sequatchie Valley and 

parts of the adjacent Valley and Ridge, Tennessee: U.S. 

Geol. Survey Prof. Paper 996, p. 8-9, 20-21 

4. Silty glauconitic limestone, overlain by argillaceous limestone, calcisiltite, and calcarenite 

5. Gray to greenish-gray 

6. 29 m 7. Fossiliferous 

8. Fernvale Member 

9. Overlies Leipers Formation; underlies Rockwood Formation 

10. Type section: Roadcuts along W lane of U.S. Highway I-24 

near Shellmound, a few hundred m W of Jasper interchange, 

Marion County, Tenn. 

Sherd Lake Till 

1. Pleistocene 

2. Wyoming (NC) 

3. Nelson, R. S., 1977, Glacial deposits of the Lake Angeline 

quadrangle, Bighorn Mountains, Wyoming: Earth Sci. Bull., v • 1 0 , no • 1 , p • 1 6 

4. Cobble and boulder till in sand and clay matrix 

5. Pinkish, weathers light yellowish brown 

6. Range 3-15 m 7. Loose, uncompacted; terminal, recessional, and ground 

moraines 

9. Overlies Circle Park Till; underlies Long Lake Till 

10. Type locality: Moraine surrounding Sherd Lake, S1/2 

sec. 30, T. 50 N., R. 84 W., Bighorn Mountains, Johnson 

County, Wyo. 

Shuyak For.ation 

1. Late Triassic 

2. Alaska (C) 

3. Connelly, William, 1978, Uyak Complex, Kodiak Islands, 
156 

4. 

6. 

7. 

8. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Alaska--a Cretaceous subduction complex: Geol. Soc. America 

Bull., v. 89, no. 5, p. 755-769 

Pillowed greenstone with interbedded limestone, breccia, 

agglomerate, and tuff; volcaniclastic turbidites, conglomerate, siliceous tuff, and argillite 

>7,000 m Well-bedded, represents seaward margin of lower Mesozoic 

forearc basin 

Informal lower volcanic member and upper sedimentary member 

Structurally overlies Kodiak Islands schist terrane and Uyak 

Complex but is separated from them by Afognak pluton 

Type section: N shore of W part of Shuyak Strait, Shuyak 

Island, N Kodiak Islands, Alaska. 

Sierra Ladrones Formation (Santa Fe Group) 

1. Pliocene, early, to Pleistocene, middle 

2. New Mexico (C) 

3. Machette, M. N., 1978, Geologic map of the San Acacia quadrangle, Socorro County, New Mexico: U.S. Geol. Survey Geol. 

Quad. Map GQ-1415 

4. Sand, sandstone, silt, fanglomerate, basalt 

5. Brown, gray 

6. >470 m 

7. Medium- to massively bedded or crossbedded alluvial fan to 

flood plain deposits; basalt top has pillow lava structure, 

central part massive, base auto-brecciated 

8. Informal basalt, piedmont slope and alluvial fan and axial 

stream deposit parts 

9. Unconformably overlies Popotosa Formation (Santa Fe Group);. 

top eroded 

10. Composite type area: Exposures of piedmont slope and alluvial fan deposits just W of Sierra Ladrones, from Rio Salado 

to N boundary of Servilleta Grant; axial stream deposit 

exposures near Loma Blanca; piedmont slope and alluvial flat 

deposit exposures N and E of San Acacia dam. Named for 

Sierra Ladrones, Socorro County, N. Mex. 

Sierra Madre Granite 

1. Early Proterozoic 

2. Wyoming (SC) 

3. Divis, A. F., 1976, Geology and geochemistry of Sierra Madre 

Range, Wyoming: Colorado School Mines Quart., v. 71, no. 3, 

p. 31-34 

4. Alaskitic granite 

5. Pink to red 

7. Medium- to fine-grained protoclastic phase; medium- to 

coarse-grained massive, equigranular phase; porphyritic 

phase; augen gneiss marginal unit; batholith and dikes 

9. Intrudes Big Creek Gneiss and intergrades with it through 

augen gneiss marginal unit; intruded by white quartz 

monzonite 

10. Type area: Major Proterozoic intrusive rock in Sierra Madre 

Range, Carbon County, Wyo. 

Silver Shield Quartz Latite 

1. Miocene, middle 

2. Utah (C) 

3. Morris, H. T., and Lovering, T. s., 1979, General geology 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

and mines of the East Tintic mining district, Utah and Juab 

Counties, Utah: U.S. Geol. Survey Prof. Paper 1024, 

p. 61-65 

4. Quartz latite 

5. Dark-gray 

6. Range 2-38 m 

7. Coarse-grained, porphyritic; dike and flow unit 

9. Intrudes Packard Quartz Latite; intrudes and disconformably 

overlies Pinyon Creek Conglomerate 

10. Type locality: Exposures in SE1/4 sec. 35, T. 9 S., 

R. 2 W., and adjacent parts of sees. 1 and 2, T. 10 S., 

R. 2 w., NE of Silver Shield (Independence) shaft, East 

Tintic mining district, NE Eureka quadrangle, Utah County, 

Utah. 

Sinawava Member (Temple Cap Sandstone) 

1. Middle Jurassic 

2. Utah (SW) 

3. Peterson, Fred, and Pipiringos, G. N., 1979, Stratigraphic 

relations of the Navajo Sandstone to Middle Jurassic formations in parts of southern Utah and northern Arizona: U.S. 

Geol. Survey Prof. Paper 1035-B, p. B8-B9 

4. Sandstone interbedded with silty sandstone and mudstone 

5. Reddish-brown 

6. 6.1 m, range 2.4-113.4 m 7. Very fine to fine-grained, some beds contain scattered coarse grains or small pebbles; slope-forming 

157 

9. Unconformably(?) overlies Navajo Sandstone (Glen Canyon 

Group); underlies White Throne Member (Temple Cap Sandstone) 

10. Type section: At top of Zion Canyon about 500 m NE of 

Observation Point, NW1/4NW1/4 sec. 2, T. 41 S., R. 10 W., 

Zion National Park, Washington County, Utah. Named for 

Temple of Sinawava in Zion Canyon, 1 km NW of type section. 

Sinepuxent Formation 

1. Pleistocene (Wisconsinan) 

2. Maryland (SE), Delaware, Virginia 

3. Owens, J. P., and Denny, C. s., 1979, Upper Cenozoic 

deposits of the central Delmarva Peninsula, Maryland and 

Delaware: U.S. Geol. Survey Prof. Paper 1067-A, p. A22-A24 

4. Micaceous sand with beds of black clay and peat 

6. >18 m 

7. Sand coarsens upward; marginal marine deposit, fossiliferous 

9. Unconformably, from N to S, overlies Omar Formation, 

Beaverdam Sand, and so-called "Yorktown(?) and Cohansey(?)" 

Formations 

10. Type locality: Drill holes in Sinepuxent Neck Peninsula 

between Berlin and Ocean City, Worcester County, Md. 

Singatse Tuff 

1. Oligocene 

2. Nevada (WC) 

3. Proffett, J. M., Jr., and Proffett, B. H., 1976, Stratigraphy of the Tertiary ash-flow tuffs in the Yerington 

district, Nevada: Nevada Bur. Mines and Geology Rept. 27, 

p. 19-20 

4. Ash-flow tuff 

5. Brown to red-brown 
158 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Range 240-460 m 

Welded, crystal-rich cooling unit; prominent ridge former 

Overlies Mickey Pass Tuff; underlies Bluestone Mine Tuff 

with erosional unconformity 

Type area: N of Singatse Peak, sec. 13, T. 13 N., R. 24 E., 

Singatse Range, Lyon County, Nev. 

Sissel Gulch Graywacke 

1. Ordovician(?) 

2. California (NW) 

3. Hotz, P. E., 1977, Geology of the Yreka quadrangle, Siskiyou 

County, California: U.S. Geol. Survey Bull. 1436, p. 12-14 

4. Graywacke 

5. Greenish-gray 

6. Range 600-700 m 7. Fine-grained, hard; faint parting plane parallel to bedding 

9. Overlies greenschist on thrust fault; conformably(?) underlies Ouzel Phyllite 

10. Type locality: Upper Moffett Creek drainage, including 

Sissel Gulch, from SW1/4 sec. 32, T. 43 N., R. 7 W., to 

S boundary of Yreka quadrangle, sec. 7, T. 42 N., R. 7 W., 

Siskiyou County, Calif. 

Sisson Member (St. Louis Limestone) 

1. Late Mississippian 

2. Indiana (SW) 

3. Keller, S. J., and Becker, L. E., 1980, Subsurface stratigraphy and oil fields in the Salem Limestone and associated 

rocks in Indiana: Indiana Geol. Survey Occasional Paper 30, 

p. 11-15 

4. Calcarenite limestone facies interbedded with dolomite, 

shale, evaporite, and crystalline limestone 

5. Tan 

6. 37 m 

7. Medium-grained, fossiliferous 

9. Overlies Salem Limestone; underlies St. Louis Limestone 

10. Type section: T & H No. 1 Lane well, depth-interval 640-

677 m, sec. 10, T. J N., R. 10 W., Knox County, Ind. Named 

for small community of Sisson in sec. 7, T. 1 N., R. 10 W. 

Skillern Chert Member (Rockwood Formation) 

1. Early Silurian 

2. Tennessee (SC) 

3. Milici, R. C., and Wedow, Helmuth, Jr., 1977, Upper 

Ordovician and Silurian stratigraphy in Sequatchie Valley 

and parts of the adjacent Valley and Ridge, Tennessee: U.S. 

Geol. Survey Prof. Paper 996, p. 9, 23-24 

4. Chert interbedded with sandy limestone 

5. Gray-green to gray-brown limestone, gray to black chert 

6. 13 m 7. Uneven bedding, some chert nodules 

9. In lower part of Rockwood Formation 

10. Type section: Exposures along Skillern Creek and its 

tributaries and in Skillern Cove along Tennessee Highway 30, 

about 5 km SE of Pikeville, Bledsoe County, Tenn. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Skyline Trail Conglomerate Member (Hoback Format1on) 

1. Paleocene, late, or Eocene, early 

2. Wyoming (WC) 

3. Dorr, J. A., Jr., Spearing, D. R., and Steidtmann, J. R., 

1977, Deformation and deposition between a foreland uplift 

and an impinging thrust belt~-Hoback Basin, Wyoming: Geol. 

Soc. America Spec. Paper 177, P• 15-20 

4. Conglomerate with lenses of clay and silt 

5. Red matrix 

6. 500 m 

7. Coarse clasts in sparse clay and silt matrix; alluvial-fan 

deposit 

9. Conformably overlies main body of Hoback Formation on NW 

margin of Hoback Basin; unconformably underlies patches of 

Pleistocene moraine 

10. Type area: Exposures in high, narrow valley between Hoback 

and Gros Ventre Ranges, extending from W side of Granite 

Creek NW to headwater area of North Fork of Horse Creek, 

along Skyline Trail, T. 39 N., R. 113 W., toT. 40 N., 

R. 115 W., Teton County, Wyo. 

Slaughterhouse Gneiss 

1. Precambrian, late 

2. Maryland (NC) 

159 

3. Crowley, W. P., 1976, The geology of the crystalline rocks 

near Baltimore and its bearing on the evolution of the eastern Maryland Piedmont: Maryland Geol. Survey Rept. Inv. 27, 

p. 5-6, 21 

4. Microcline-quartz-plagioclase granitic gneiss 

5. Pink- to orange-weathering 

7. Medium-grained, uniform, well-foliated to massive; of probable pre-Glenarm intrusive origin 

9. Forms three discrete masses within Baltimore Gneiss 

10. Type locality: Outcrops along Slaughterhouse Branch SE of 

Baltimore Beltway, U.S. Highway I-695, Cockeysville quadrangle, Baltimore County, Md. 

Slaughterhouse Marble (Libby Creek Group) 

1. Early Proterozoic 

2. Wyoming (SC) 

3. Divis, A. F., 1976, Geology and geochemistry of Sierra Madre 

Range, Wyoming: Colorado School Mines Quart., v. 71, no. 3, 

p. 27-28 

4. Siliceous marble with interbedded phyllite and calcitic 

schist 

6. 300 m 

7. Massive, fine- to medium-grained 

9. Lithologically similar to Nash Fork Formation (Libby Creek 

Group) in Medicine Bow Range; conformably overlies Quartzite 

Peak Quartzite; uppermost formation of Libby Creek Group 

with irregular top bounded by low-angle faults 

10. Type area: Exposed in Slaughterhouse Gulch N of North Fork 

of Encampment River, Sierra Madre Range, Carbon County, Wyo. 

Slope Formation (Fort Union Group) 

1. Paleocene 

2. North Dakota (SW), Montana 

3. Clayton, Lee, and others, 1977, The Slope (Paleocene) and 
160 

4. 

5. 

6. 

7. 

B. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Bullion Creek (Paleocene) Formations of North Dakota: North 

Dakota Geol. Survey Rept. Inv. 59, p. 7-9 

Alternating beds of clay, silt, sand, and lignite 

Brownish-gray, bleached white at top 

90 m 

Unlithified or moderately lithified; unbedded or thinly 

laminated 

Informal white marker zone at top of Slope Formation 

Overlies Cannonball or (at type section) Ludlow Formation; 

unconformably underlies Bullion Creek Formation 

Type section: S-facing exposure in NW1/4 sec. 10, 

T. 105 N., R. 135 W., Slope County, N.Dak. Named for Slope 

County. 

Smelser 

1 0 

2. 

3. 

Pass Member (Augusta Mountain Formation) 

Middle and Late Triassic (Ladinian and Karnian) 

Nevada (NC) 

Nichols, K. M., and Silberling, N. J., 1977, Stratigraphy 

and depositional history of the Star Peak Group (Triassic), 

northwestern Nevada: Geol. Soc. America Spec. Paper 178, 

p. 31-34 

4. 

5. 

6. 

7. 

9. 

10. 

Limestone capped by mafic volcanic rocks 

Dark-gray, mottled 

180 m, range 180-400 m Medium- to thick-bedded, bioturbated, blocky weathering, 

cliff-forming, intertidal to subtidal deposits 

Conformably overlies Panther Canyon Member (Augusta Mountain 

Formation); unconformably underlies Cane Spring Formation 

(both formations are in Star Peak Group) 

Type section: Near Smelser Pass, N end of China Mountain, 

T. 32 N., R. 40 E., Pershing County, Nev. 

Smeltertown Formation (Washita Group) 

1. Early Cretaceous (Comanchean) 

2. New Mexico (SC), Texas, Mexico 

3. Strain, W. S., 1976, New formation names in the Cretaceous 

at Cerro de Cristo Rey, Dona Ana County, New Mexico, 

Appendix 2, in Lovejoy, E. M. P., Geolo~y of Cerro de Cristo 

Ray uplift, Chihuahua and New Mexico: New Mexico Bur. Mines 

and Mineral Resources Mem. 31, p. 78-79 

4. Shale with interbedded sandstone, siltstone, and limestone 

5. Olive-gray, dark-gray 

6. 61.4 m, range 30-61.4 m 7. Sole marks common 

9. Conformably overlies Del Norte Formation; conformably underlies Muleros Formation 

10. Type section: N side of arroyo trending S 70° W from kilns 

at El Paso Brick Co. plant, NW1/4SW1/4NW1/4 sec. 15 and 

SE1/4SE1/4NE1/4 sec. 16, T. 29 S., R. 4 E., Dona Ana County, 

N. Mex. Named for community of Smeltertown in El Paso, El 

Paso County, Tex. 

Smutty Hollow Member (Ammonoosuc Formation) 

1. Middle Ordovician 

2. New Hampshire (WC) 

3. Prager, G. D., 1980, Stratigraphy of the Gardner Mountain 

area, New Hampshire: Northeastern Geology, v. 2, no. 1, 

p. 34 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

4. Calcareous chlorite schist 

5. Blue-gray 

7. Massive 

9. Overlies West Bath Member (Ammonoosuc Formation); underlies 

Partridge Formation 

161 

10. Type locality: In Smutty Hollow Brook, 0.4 km E of Connecticut River, Grafton County, N.H. 

Snaky canyon Formation 

1. Late Mississippian to Early Permian (Chesterian to 

Wolfcampian) 

2. Idaho (SE) 

3. Skipp, Betty, and others, 1979, Upper Paleozoic carbonate 

bank in east-central Idaho--Snaky Canyon, Bluebird Mountain, 

and Arco Hills Formations, and their paleotectonic significance: U.S. Geol. Survey Bull. 1486, p. 20-32 

4. Limestone and dolomite, locally oolitic and cherty, interbedded with calcareous sandstone 

5. Medium- to light-gray 

6. 1, 300 m 7. Medium- to thin-bedded, microcrystalline to medium-grained, 

variably fossiliferous 

8. Bloom, Gallagher Peak Sandstone, and Juniper Gulch Members 

9. Gradationally overlies Bluebird Mountain Formation; conformably underlies Phosphoria Formation 

10. Type section: Designated for each member. Named for Snaky 

Canyon, Snaky Canyon quadrangle, Clark County, Idaho. 

Sneakover Limestone Member (Orr Formation) 

1. Late Cambrian 

2. Utah (WC) 

3. Hintze, L. F., and Palmer, A. R., 1976, Upper Cambrian Orr 

Formation--its subdivisions and correlatives in western 

Utah: U.S. Geol. Survey Bull. 1405-G, p. G8-G9, G12-G13 

4. Calcarenite, calcisiltite 

5. Gray 

6. 56.4 m, range 50-60 m 

7. Fossiliferous, ledge-forming 

9. Conformably overlies Corset Spring Shale Member or Steamboat 

Pass Shale Member (Orr Formation); conformably underlies 

Notch Peak Formation 

10. Type section: NE side of Orr Ridge, along ridge between 

Little Horse Canyon and Big Horse Canyon, NE1/4 sec. 33, 

T. 18 S., R. 13 W., House Range, Notch Peak quadrangle, 

Millard County, Utah. Named for Sneakover Pass in House 

Range. 

Solon Formation 

1. Early Devonian(?) 

2. Maine (WC) 

3. Pankiwskyj, K. A., and others, 1976, Stratigraphic relationships on the southeast limb of the Merrimack synclinorium in 

central and west-central Maine: Geol. Soc. America 

Mem. 146, p. 270, 275 

4. Metapelite with minor metasiltstone, metasandstone, and 

metaconglomerate 

5. Silvery-gray 

6. >2,000 m 
162 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Massive to rhythmically interbedded and thinly laminated 

Conformably and gradationally overlies. Fall Brook Formation; 

upper contact not exposed (top eroded) 

Type locality: Tops and slopes of Whipple and French Hills, 

Township of Solon, N Anson quadrangle, Somerset County, 

Maine. 

Solstice Canyon Tongue (Conejo Volcanics) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E23 

4. Basaltic and andesitic flows, breccias, and tuffs 

6. 244 m 

9. Overlies Latigo Canyon Breccia Member (Calabasas Formation); 

intertongues with Dry Canyon Sandstone Member (Calabasas 

Formation); underlies Malibu Bowl Tongue (Conejo Volcanics) 

10. Type area: Solstice Canyon, Santa Monica Mountains, EC 

Point Dume quadrangle, Los Angeles County, Calif. 

Spencer 

1 • 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

Brook Member (Nashoba Formation) 

pre-Silurian 

Massachusetts (C) 

Bell, K. G., and Alvord, D. C., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 186-187, 208, app. 1 (in pocket) 

Amphibolite, minor amphibole-biotite gneiss and calcsilicate rocks 

580 m 

Stratified, relict sedimentary structures 

Overlies Billerica Schist Member; underlies Tophet Swamp 

Gneiss Member 

Type locality: Along NW side of Spencer Brook in town of 

Carlisle, Billerica quadrangle, Middlesex County, Mass. 

Spor Mountain Formation 

1. Miocene, early 

2. Utah (WC) 

3. Lindsey, D. A., 1979, Geologic map and cross-sections of 

Tertiary rocks in the Thomas Range and northern Drum Mountains, Juab County, Utah: U.S. Geol. Survey Misc. Inv. Ser. 

Map I-1176 

4. Beryllium tuff and porphyritic alkali rhyolite 

5. Tan, gray, red 

6. Lower member: range 20-60 m; upper member: 500 m max 

7. Lower member: stratified vitric tuff and tuffaceous 

breccia; upper member: flows, domes, and plugs 

8. Informal lower beryllium tuff member and upper porphyritic 

rhyolite member 

9. Unconformably overlies Dell Tuff, Drum Mountains Rhyodacite, 

Paleozoic rocks; unconformably underlies Topaz Mountain 

Rhyolite and Quaternary sediments 

10. Type section: Exposures E of Spor Mountain, sees. 8 and 9, 

T. 13 S., R. 12 W., Thomas Range, Juab County, Utah. 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Spring Garden Member (Castle Hayne Formation) 

1. Eocene, late middle (Claibornian) 

2. North Carolina (EC) 

3. Ward, L. W., Lawrence, D. R., and Blackwelder, B. W., 1978, 

Stratigraphic revision of the middle Eocene, Oligocene, and 

lower Miocene--Atlantic Coastal Plain of North Carolina: 

U.S. Geol. Survey Bull. 1457-F, p. F9-F10 

4. Siliceous biocalcirudite (limestone) 

5. Tan to gray 

6. 1.95 m, range 1.95-6 m 

163 

7. Arenaceous, well-cemented by calcite; fossiliferous (mollus- can molds filled with silica) 

9. Conformably overlies Comfort Member (Castle Hayne 

Formation); unconformably underlies River Bend Formation or Duplin Formation 

10. Type locality: Spring Garden Landing, 5.2 km ENE of Jasper, 

R bank of Neuse River, Craven County, N.C. Reference locality: Martin Marietta Co. New Bern quarry, NW of New Bern, 

Craven County. 

Springtime Canyon Quartz Latite 

1. Oligocene 

2. New Mexico (WC) 

3. Deal, E. G., and Rhodes, R. C., 1976, Volcano-tectonic 

structures in the San Mateo Mountains, Socorro County, New 

Mexico: New Mexico Geol. Soc. Spec. Pub. 5, p. 53 

4. Mixed quartz latite and rhyolite flows with sanidine and 

plagioclase phenocrysts 

6. >700 m 7. Massive; erupted from Nogal Canyon cauldron 

9. Conformably overlies Vicks Peak Rhyolite; youngest rock of 

Nogal Canyon cauldron flows 

10. Type locality: Springtime Canyon, S San Mateo Mountains, 

Socorro County, N. Mex. 

Squirrel 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Springs Canyon Andesite 

Oligocene 

New Mexico (WC) 

Rhodes, R. C., and Smith, E. I., 1976, Stratigraphy and 

structure of the northwestern part of the Mogollon Plateau 

Volcanic Province, Catron County, New Mexico: New Mexico 

Geol. Soc. Spec. Pub. 5, p. 59 

Andesite flows 

Dark-gray to reddish-black 

200 m, range 20-200 m Coarsely porphyritic 

Conformably overlies or interfingers with Tularosa Canyon 

Rhyolite; underlies Apache Spring Quartz Latite 

Type section: Tularosa Canyon, sec. 33, T. 6 s., R. 18 W., 

Catron County, N. Mex. Named for Squirrel Springs Canyon near John Kerr Peak, Catron Tularosa Mountains. 

Stagg Creek Member (Doswell Formation) 

1. Late Triassic 

2. Virginia (EC) 

3. Weems, R. E. 1980, Geology of the Taylorsville basin, 

Hanover County, Virginia: Virginia Div. Mineral Resources 

Pub. 27, p. 24-25 
164 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Sandstone, conglomerate, minor siltstone 

Grayish-orange, dark-red 

232.6 m 

Massive, coarse-grained 

Nonconformably overlies Petersburg Granite; conformably 

underlies Falling Creek Member (Doswell Formation) 

Type section: Along Stagg Creek, beginning at Hanover 

Country Club 0.3 km N of Virginia Highway 54 and continuing 

S to contact with Petersburg Granite, Taylorsville basin, 

Hanover Academy quadrangle, Hanover County, Va. 

Steaaboat Pass Sbale Member (Orr Formation) 

1. Late Cambrian 

2. Utah (WC) 

3. Hintze, L. F., and Palmer, A. R., 1976, Upper Cambrian Orr 

Formation--its subdivisions and correlatives in western 

Utah: U.S. Geol. Survey Bull. 1405-G, p. G7-G8, G20-G21 

4. Shale, limestone (calcisiltite, calcarenite) 

5. Gray 

6. 260 m 

7. Fossiliferous, slope-forming 

9. Conformably overlies Big Horse Limestone Member; conformably 

underlies Sneakover Limestone Member; equivalent of Candland 

Shale Member and Corset Spring Shale Member where these 

cannot be mapped separately because Johns Wash Member is 

absent 

10. Reference section: Best exposures known, 0.8 km W of Lawson 

Cove Reservoir on E side of Hill 6190, SW1/4 sec. 29, 

T. 24 S., R. 14 W., Wah Wah Mountains, Frisco Peak quadrangle, Millard County, Utah. Named for exposures on N side 

of Steamboat Pass, sec. 19, T. 23 S., R. 13 W., The Barn 

quadrangle. 

Stewart Gulch Tongue (Green River Formation) 

1. Eocene 

2. Colorado (NW) 

3. Hail, W. J., Jr., 1977, Stewart Gulch Tongue--a new tongue 

of the Eocene Green River Formation, Piceance Creek basin, 

Colorado: U.S. Geol. Survey Bull. 1422-E, p. 1-8 

4. Marlstone 

5. Light-gray 

6. 15.2 m, range 3-17 m 7. Forms prominent outcrops 

9. One of several units of the Green River Formation which 

tongue northward into the Uinta Formation and merge southward with the Parachute Creek Member (Green River Formation). Overlies Coughs Creek Tongue; underlies marlstone at 

Barnes Ridge 

10. Type section: SW1/4NE1/4NW1/4 sec. 3, T. 4 S., R. 96 W., 

about 730 m E of road along Middle Fork of Stewart Gulch, 

tributary of Piceance Creek, and about 150 m above valley 

bottom. Rio Blanco County, Colo. 

Stokes Canyon Breccia Meaber (Calabasas Formation) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central s~nta Monica Mountains, Los 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 165 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E22 

4. Sedimentary breccia 

6. 60 m 

1. Consists of angular fragments of redeposited sandstone that 

carry Paleocene and Eocene mollusks 

9. Prominent interbed in Calabasas Formation, which is otherwise undivided in Stokes Canyon area 

10. Type locality: Stokes Canyon area, SW1/4 sec. 33, T. 1 N., 

R. 17 w., and NW1/4 sec. 4, T. 1 s., R. 17 W., NC Santa 

Monica Mountains, Malibu Beach quadrangle, Los Angeles 

County, Calif. 

Stoney Fork Meaber (Breathitt Formation) 

1. Middle Pennsylvanian (Atokan) 

2. Kentucky (SE) 

3. Ping, R. G., and Rice, C. L., 1979, Stoney Fork Member (new 

name) of the Breathitt Formation in southeasternmost 

Kentucky: U.S. Geol. Survey Bull. 1482-A, p. A70-A76 

4. Shale, limestone, siltstone, and sandstone in upward coars- ening sequence 

5. Medium-dark-gray 

6. 10.43 m, range 6-12 m 

1. Fossiliferous, contains siderite layers or nodules 

9. Overlies Magoffin Member; unconformably underlies unnamed 

sandstone and coal beds 

10. Type section: • Strip bench 350 m SE of Kentucky State 

Highway 1201 at head of Red Bird Creek, 4.8 km SW of community of Beverly, Beverly quad~angle, Bell County, Ky. Named 

for settlement of Stoney Fork, about 8 km S of type section. 

Stony Creek Formation 

1. Late Jurassic and Early Cretaceous 

2. California (NW) 

3. Ingersoll, R. V., Rich, E. I., and Dickinson, W. R., 1977, 

Field guide--Great Valley Sequence, Sacramento Valley: 

Geol. Soc. America, Cordilleran Sec., Ann. Mtg., [Guidebook 

8J, p. 28-30 

4. Siltstone and mudstone with lenses of sandstone and 

conglomerate 

5. Greenish-gray to black 

6. 4,100 m 1. Thin-bedded to laminated siltstone; predominantly andesitic 

detritus deposited in deep-marine trough; basal unit of 

Great Valley sequence 

8. Informal basaltic sandstone member 

9. In fault contact with serpentinite basement rocks; conformably underlies Lodoga Formation, or is locally truncated by 

its basal Leesville Sandstone Member 

10. Type section: Along Stony Creek, 6.4 km NE of town of 

Stonyford, Lodoga quadrangle, Glenn County, Calif. 

Stroh Member (Cataract Formation) 

1. Middle Silurian 

2. Indiana (NE) 

3. Rexroad, c. B., 1980, Stratigraphy and conodont paleontology 

of the Cataract Formation and the Salamonie Dolomite 
166 

4. 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

(Silurian) in northeastern Indiana: Indiana Geol. Survey 

Bull. 58, p. 12-14 

Argillaceous dolomite with thin shale interbeds 

Tan, brown, green 

3.3 m 

Fine-grained, fossiliferous 

Unconformably overlies Cabot Head Member (Cataract 

Formation); conformably underlies Salamonia Dolomite 

Type section: Northern Indiana Public Service Co. Arden 

Tubbs No. 1 hole, depth-interval 456-459.3 m, 

SW1/4SE1/4SW1/4 sec. 27, T. 36 N., R. 12 E., Steuben County, 

Ind. Named for town of Stroh, 7.2 km NW of type section. 

St. Wendel Metagabbro (Sauk Rapids Metamorphic Complex) 

1. Precambrian, early 

2. Minnesota (C) 

3. Morey, G. B., 1978, Lower and middle Precambrian stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol. Survey Rept. Inv. 21, p. 11 

4. Plagioclase-clinopyroxene gneiss 

5. Greenish-gray to greenish-black 

7. Lenticular bodies 125-300 m wide and 300-2,000 m long, 

elongated to E, parallel to foliation of enclosing rocks 

9. Enclosed in Sartell Gneiss (Sauk Rapids Metamorphic Complex) 

10. Type locality: Abandoned quarry, SE1/4SE1/4 sec. 12, 

T. 125 N., R. 29 W., St. Wendel Township, Stearns County, 

Minn. 

Sumas Mountain Subgroup (Chilliwack Group) 

1. Devonian 

2. Washington (NC) 

3. Danner, W. R., 1977, Paleozoic rocks of northwest Washington 

and adjacent parts of British Columbia, in Stewart, J. H., 

and others, eds., Paleozoic paleogeography of the western 

United States--Pacific Coast Paleogeography Symposium 1 

[Bakersfield, Calif., 1977]: Los Angeles, Soc. Econ. 

Paleontologists and Mineralogists, Pacific Sec., p. 487-489 

4. Limestone, with shale, graywacke, argillite, and volcanic 

rocks 

6. Range 610-915 m 

7. Limestone: fossiliferous, argillaceous micrite, layered 

skeletal reefs; isoclinal folds, imbricate faults 

9. Lowest division of Chilliwack Group; lower contact not 

stated; underlies Red Mountain Subgroup 

10. Type area: Doaks Creek quarry on E side of Red Mountain, 

and quarry exposures on Sumas Mountain, Whatcom County, 

Wash. 

Sunken Meadow Member (Yorktown Formation) 

1. Pliocene, early 

2. Virginia (SE), North Carolina 

3. Ward, L. W., and Blackwelder, B. W., 1980, Stratigraphic 

revision of upper Miocene and lower Pliocene beds of the 

Chesapeake Group, middle Atlantic Coastal Plain: U.S. Geol. 

Survey Bull. 1482-D, p. 032-036 

4. Shelly sand 

5. Tan 

6. 2.5 m, range <1-3 m 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

7. Poorly sorted, coarse- to medium-grained 

9. Unconformably overlies Cobham Bay Member (Eastover 

Formation); conformably underlies Rushmere Member (Yorktown 

Formation) 

167 

10. Type section: Exposures 1.3 km below mouth of Sunken Meadow 

Creek, R bank of James River, Surry County, Va. 

SUnrise Peak Monzonite Porphyry 

1. Oligocene, middle 

2. Utah (C) 

3. Morris, H. T., and Lovering, T. S., 1979, General geology 

and mines of the East Tintic mining district, Utah and Juab 

Counties, Utah: U.S. Geol. Survey Prof. Paper 1024, 

p. 41-44 

4. Monzonite porphyry 

5. Dark-gray to greenish-gray 

6. Gough sill: range 152 to 305 m 

7. Fine- to medium-grained, stock and sill-like intrusive 

bodies 

8. Informal Sunrise Peak stock and Gough sill 

9. Intrudes and is genetically equivalent to Tintic Mountain 

Volcanic Group 

10. Type locality: Sunrise Peak stock that underlies Sunrise 

Peak in SC part of main Tintic mining district, sec. 17, 

T. 11 S., R. 2 W., 9.6 km SSW of Dividend, Juab County, 

Utah. 

Sunset Creek Intrusive Complex 

1. Precambrian, early [Late Archean] 

2. Michigan (NW) 

3. Schmidt, R. G., 1976, Geology of the Precambrian W (lower 

Precambrian) rocks in western Gogebic County, Michigan: 

U.S. Geol. Survey Bull. 1407, p. 26-28 

4. Leucocratic pegmatite, including granitic and aplitic 

phases, minor quartz monzonite 

7. Multitextured pegmatite dikes and small, irregular intrusive 

bodies; even-textured quartz monzonite dikes 

9. Intrusive in Puritan Quartz Monzonite, Whiskers Creek 

Gneiss, and Ramsay Formation 

10. Type locality: Exposures in large bedrock hill, NW1/4NW1/4 

sec. 25, T. 47 N., R. 46 W., NE of Sunset Creek, Gogebic 

County, Mich. 

Swauk Prairie Member (Kittitas Drift) 

1. Pleistocene 

2. Washington (C) 

3. Porter, s. C., 1976, Pleistocene glaciation in the southern 

part of the North Cascade Range, Washington: Geol. Soc. 

America Bull., v. 87, no. 1, p. 66-67 

4. Stony till, gravel 

7. Moraine complex, outwash; mantled by loess 

8. Till and outwash facies 

9. Overlies Thorp Drift; underlies Indian John Member (Kittitas 

Drift) 

10. Type locality: Till facies: roadcut along U.S. Highway 97 

at NW end of Swauk Prairie, SE1/4NW1/4 sec. 28, T. 20 N., 

R. 17 E., and canal cut on Thorp Prairie, SW1/4NE1/4 

sec. 30, T. 19 N., R. 17 E.; outwash facies: roadcut near 
168 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

distal margin of Thorp Prairie moraine, SE1/4SW1/4 sec. 32, 

T. 19 N., R. 17 E., upper Yakima Riv~r drainage basin, 

Kittitas County, Wash. 

Sweathouse Amphibolite Member (Oella Formation) 

1. Cambrian-Ordovician(?) 

2. Maryland (NC) 

3. Crowley, W. P., 1976, The geology of the crystalline rocks near Baltimore and its bearing on the evolution of the 

eastern Maryland Piedmont: Maryland Geol. Survey Rept. 

Inv. 27, p. 11, 24-25 

4. Schist and gneiss interlayered with epidote amphibolite 

6. Range <1-700 m 

7. Mixed metasedimentary-metavolcanic unit; host rock of Bare 

Hills Copper deposit 

9. Overlies lower unnamed metasedimentary unit of Oella Formation; underlies Sykesville Formation 

10. Type locality: Outcrops along Sweathouse Branch, tributary 

of Gunpowder Falls, E from mouth to Mountvista Road, 

Baltimore County, Md. 

Swede Road Member (Bush Bay Dolostone) 

1. Middle Silurian (Niagaran) 

2. Michigan (EC) 

3. Johnson, A. M., and others, 1979, The Maple Block knoll reef 

in the Bush Bay Dolostone (Silurian, Engadine Group), 

Northern Peninsula of Michigan: Michigan Univ. Mus. Paleontology Papers on Paleontology, no. 20, p. 14-18 

4. Dolomite 

5. Buff-brown 

6. 10 m 

7. Massive, but weathers to thin beds; fine-grained to finely 

crystalline, sandy, interreefal deposits, fossil-poor 

9. Overlies Prentiss Creek Member; underlies McKay Bay Member 

10. Type locality: Powerline right-of-way and U.S. Steel Corp. 

property, sec. 10, T. 42 N., R. 1 E., Mackinac County, 

Mich. Named for Swede Road, which runs along S boundary of 

sec. 10. 

Tabb Formation 

1. Pleistocene, late 

2. Virginia (SE) 

3. Johnson, G. H., 1976, Geology of the Mulberry Island, 

Newport News North, and Hampton quadrangles, Virginia: 

Virginia Div. Mineral Resources Rept. Inv. 41, p. 32-39 

4. Clayey, silty and gravelly sand, clay 

5. Gray, bluish-gray, tan, reddish-brown, yellowish-brown 

6. Range <1-3.5 m 7. Beach and nearshore marine and fluvial-estuarine deposits 

8. Sedgefield, Lynnhaven, and Poquoson Members 

9. Unconformably overlies Norfolk Formation or Yorktown 

Formation; underlies Holocene sediments 

10. Type section: Designated for each member. Named for 

village of Tabb, York County, Va. 

Tadauck Brook Schist 

1. pre-Silurian 

2. Massachusetts (C) 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

3. Bell, K. G., and Alvord, D. c., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 184-195, 210-211, app. 1 (in pocket) 

4. Aluminous schist interstratified with minor amphibolite and 

quartzite 

5. Medium-dark- to silvery-gray, weathers rusty 

6. 920 m 

7. Stratified, relict sedimentary structures 

9. Lower beds intertongued with, or in fault contact with 

underlying Nashoba Formation; top truncated by ClintonNewbury fault zone 

10. Type locality: Area on both sides of Tadmuck Brook in town 

of Westford, delineated on SE side by upper forks of brook 

and on NW side by Lowell Road, Westford quadrangle, 

Middlesex County, Mass. 

Tangle Lakes Formation (Amphitheater Group) 

1. Late Triassic 

2. Alaska (EC) 

3. Stout, J. H., 1976, Geology of the Eureka Creek area, eastcentral Alaska Range: Alaska Div. Geol. and Geophys. 

Surveys Geol. Rept. 46, p. 12-14 

4. Siliceous tuff, agglomerate, pillowed andesite and basalt 

5. Green to gray 

6. 3,500 m 

169 

9. Overlies Paxson Mountain Basalt (Amphitheater Group); underlies Boulder Creek Volcanics (Amphitheater Group); intruded 

by Fish Lake Complex 

10. Type locality: S limb of Amphitheater syncline near Tangle 

Lakes and upper Delta River, Eureka Creek area, Mount Hayes 

A-4 and A-5 quadrangles, EC Alaska Range, Alaska. 

Ta River Meta.orphic Suite (Fredericksburg Complex) 

1. Early Cambrian(?) 

2. Virginia (EC) 

3. Pavlides, Louis, 1980, Revised nomenclature and stratigraphic relationships of the Fredericksburg Complex and 

Quantico Formation of the Virginia Piedmont: U.S. Geol. 

Survey Prof. Paper 1146, p. 7-12 

4. Amphibole gneiss, biotite gneiss, schist, metagabbro, granitoid rocks 

5. Dark-gray to black 

7. Foliated 

9. Possibly an eastern equivalent of Chopawamsic Formation; in 

contact with Po River Metamorphic Suite along Spotsylvania 

lineament; underlies Quantico Formation with angular 

unconformity 

10. Type area: Exposures along Virginia Route 656 which crosses Ta River, SE corner of Brokenburg quadrangle, Spotsylvania 

County, Va. 

Tavernier Tongue (Rebecca Shoal Dolomite) 

1. Paleocene 

2. Florida (SE) 

3. Winston, G. 0., 1978, Rebecca Shoal reef-complex (Upper 

Cretaceous and Paleocene) in south Florida: Am. Assoc. 

Petroleum Geologists Bull., v. 62, no. 1, p. 124-127 

4. Anhedral dolomite 
170 

5. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Brown, cream 

239 m Subsurface, barrier-reef complex; fine-crystalline 

Overlies Plantation Tongue (Rebecca Shoal Dolomite); interfingers with Cedar Keys Formation 

Type section: Coastal Petroleum 1 State well 363, depthinterval 1,181-1,420 m, sec. 32, T. 62 S., R. 38 E., Monroe 

County, Fla. Named for town of Tavernier on Plantation Key, 

3.2 km E of well. 

Teklanika Formation 

1. Paleocene 

2. Alaska (C) 

3. Gilbert, W. G., Ferrell, V. M., and Turner, D. L., 1976, The 

Teklanika Formation--a new Paleocene volcanic formation in 

the central Alaska Range: Alaska Div. Geol. and Geophys. 

Surveys Geol. Rept. 47, p. 1-16 

4. Andesite, rhyolite, and basalt flows, with interbedded 

felsic pyroclastic mudstone, tuff, and tuff breccia 

5. Dark-gray, weathers brown and purple 

6. >3,750 m 

8. Informal units A, B, C, D, E, F 

9. Conformably and unconformably overlies Cantwell Formation; 

unconformably underlies Quaternary alluvium 

10. Type section: Ridge along E side of upper Teklanika River, 

from 6.5 to 5 km S of Calico Creek, Mount McKinley National 

Park, C Alaska Range, Healy C-6 quadrangle, Alaska. 

Tbt.ble Limestone Member (Carrara Formation) 

1. Early Cambrian 

2. California (EC), Nevada 

3. Palmer, A. R., and Halley, R. B., 1979, Physical stratigraphy and trilobite biostratigraphy of the Carrara Formation 

(Lower and Middle Cambrian), southern Great Basin: U.S. 

Geol. Survey Prof. Paper 1047, p. 13 

4. Limestone 

5. Black, brown, and orange 

6. Range <1->50 m 7. Thin-bedded, each bed a couplet: lower part calcarenite, 

upper part argillaceous or dolomitic; fossiliferous 

9. Conformably overlies Eagle Mountain Shale Member; underlies 

Echo Shale Member 

10. Type locality: Exposures on W side of Titanothere Canyon 

below Thimble Peak, Grapevine Mountains, Inyo County, Calif. 

Third Beach ~ber (Makah Formation) 

1. Eocene, late 

2. Washington (NW) 

3. Snavely, P. D., Jr., and others, 1980, Makah Formation--a 

deep-marginal-basin sequence of late Eocene and Oligocene 

age in the northwestern Olympic Peninsula, Washington: U.S. 

Geol. Survey Prof. Paper 1162-B, p. 9-11 

4. Micaceous sandstone with siltstone interbeds and calcareous 

concretions 

5. Weathers grayish orange 

6. 43 m 1. Thick-bedded, amalgamated turbidite beds, ridge-forming 

9. Lies 290 m above Klachopis Point Member and 250 m below 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Jansen Creek Member; upper and lower contacts with unnamed 

siltstone and sandstone in middle part of Makah Formation 

are generally covered 

171 

10. Type section: Wave-cut terrace and headland E of Third 

Beach, SE1/4SW1/4 sec. 7, T.'33 N., R. 14 W., Strait or Juan 

de Fuca, Clallam County, Wash. 

Thirtyone Formation 

1. Early Devonian 

2. Texas (WC) 

3. Hills, J. M., and Hoenig,~· A., 1979, Proposed type 

sections for Upper Silurian and Lower Devonian subsurface 

units in Permian Basin, west Texas: Am. Assoc. Petroleum 

Geologists Bull., v. 63, no. 9, p. 1513-1518 

4. Si~iceous limestone, chert 

5. Gray, white 

6. 308 m, range 30-308 m 

9. Unconformably overlies Wristen Formation; unconformably 

underlies Woodford Shale 

10. Type section: Champlin Refining Co. 1 Crane-University 

well, depth-interval 2,450-2,758 m, Sec. 40, Blk. 31, 

University Lands Survey, Crane County, Tex. Named for Block 

31 oil field. 

Thorp Drift 

1. Pleistocene 

2. Washington (C) 

3. Porter, S. C., '1976, Pleistocene glaciation in the southern 

part of the North Cascade Range, Washington: Geol. Soc. 

America Bull., v. 87, no. 1, p. 65-66 

4. Till; outwash gravel with interbedded sand and silt 

6. 140m (outwash); 1.5 m (till) 

7. Stony, fissile till, erratics with weathering rinds; poorly 

sorted, deeply oxidized braided-stream deposits 

8. Informal till and outwash facies 

9. Unconformably overlies Ellensburg Formation; underlies 

Kittitas Drift or younger Quaternary deposits 

10. Type locality: Till facies: Horse Canyon, W wall at 790 m alt., NW1/4SW1/4 sec. 4, T. 19 N., R. 17 E; outwash facies: 

landslide scarp on N side of Yakima River, 1.5 km E of 

Thorp, NE1/4 sec. 12, T. 18 N., R. 17 E, Kittitas County, 

Wash. 

Three Creeks Tuf~ MeBber (Bullion Canyon Volcanics) 

1 • Oligocene 

2. Utah (SW) 

3. Steven, T. A., and others, 1979, Revised stratigraphy and 

radiometric ages or volcanic rocks and mineral deposits in 

the Marysvale area, west-central, Utah: U.S. Geol. Survey 

Bull. 1469, p. 13-17 

4. Crystal-rich ash-flow tuff 

6. Lower part: >200 m; middle part: 200->500 m 

7. Compound cooling unit, phenocrystic; hard, densely welded 

tuffs form vertical cliffs 

8. Informal lower, middle, and upper parts 

9. As marker bed and only named member, overlies unnamed lower 

part and underlies unnamed upper part of Bullion Canyon 
172 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Volcanics. Unit was formerly Clear Creek Tuff Member of Dry 

Hollow Formation 

Type area: Cliffs along Three Creeks, upstream from mouth 

of Pole Creek, tributary to Clear Creek, Sevier County, 

Utah. Reference section: Narrows area of Clear Creek 

Canyon. 

Three Lick Bed (Ohio Shale)/(New Albany Shale)/(Chattanooga Shale) 

1. Late Devonian 

2. Kentucky (EC), Ohio, West Virginia 

3. Provo, L. J., Kepferle, R. c., and Potter, P. E., 1978, 

Division of black Ohio Shale in eastern Kentucky: Am. 

Assoc. Petroleum Geologists Bull., v. 62, no. 9, p. 1703-

1713 

4. Shale 

5. Greenish-gray, black 

6. 3.5 m, range 0.5-22.9 m 1. Plastic, conspicuous lack of silt, thin carbonate layers 

with cone-in-cone structure, burrowed zones 

9. Overlies Huron Member (Ohio Shale); underlies Cleveland 

Member (Ohio Shale). Overlies and underlies unnamed units 

of New Albany Shale in EC Kentucky (SW of type locality), 

and of Chattanooga Shale in SC Kentucky 

10. Type section: Along U.S. Highway I-64, Rowan County, Ky. 

Base of section on S side of I-64, 2.16 km E of Bath-Rowan 

County line; top of section on N side of I-64, 2.8 km NE of 

base. Named for Three Lick Branch, 3 km N of base. 

Tick Ridge Sandstone Member (Tar Springs Formation) 

1. Late Mississippian (Chesterian) 

2. Indiana (SC) 

3. Gray, H. H., 1978, Buffalo Wallow Group--upper Chesterian 

(Mississippian) of southern Indiana: Indiana Geol. Survey 

Occasional Paper 25, p. 8 

4. Sandstone 

6. 26 m 

1. Crossbedded, massive lenses; cliff-forming 

9. Sharp lower and upper contacts with enclosing Tar Springs 

Formation 

10. Type section: Taswell Section, SE1/4 sec. 6, T. 2 S., 

R. 1 W., Crawford County, Ind. Named for outcrops around 

Tick Ridge, 4 km S of Taswell. 

Tintic Delmar Latite (Laguna Springs Volcanic Group) 

1. Oligocene, middle 

2. Utah (C) 

3. Morris, H. T., and Lovering, T. S., 1979, General geology 

and mines of the East Tintic mining district, Utah and Juab 

Counties, Utah: U.S. Geol. Survey Prof. Paper 1024, 

p. 50-52 

4. Latite flows, tuff, ash, agglomeratic breccia 

5. Tuff: buff to white; flow: gray 

6. Tuff: 23-58 m; flow: 30-61 m 1. Tuff: fine- to coarse-grained, heterogeneous; flow: 

medium-grained, massive, porphyritic 

8. Informal lower tuff member and upper flow member 

9. Overlies Pinyon Queen Latite (Laguna Springs Volcanic Group) 

10. Type locality: Exposures just S of Tintic Delmar mine, 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 173 

W1/2, sec. 26, T. 9 s., R. 2 W., SC Allens Ranch quadrangle, 

Utah County, Utah. 

Ttntic Mountain Volcanic Group 

1. Oligocene, middle 

2. Utah (C) 

3. Morris, H. T., and Lovering, T. S., 1979, General geology 

and mines of the East Tintic mining district, Utah and Juab 

Counties, Utah: U.S. Geol. Survey Prof. Paper 1024, 

p. 36-41 

4. Latite flows and tuffs 

5. Green, gray, black, reddish-brown, white 

8. Copperopolis Latite, Latite Ridge Latite, and Big Canyon 

Latite 

9. Unconformably overlies Packard Quartz Latite; unconformably 

underlies Laguna Springs Volcanic Group or disconformably 

underlies Pinyon Creek Conglomerate 

10. Type locality: Exposures on lower W slopes of Tintic Mountain, 16 km S of Dividend, Juab County, Utah. 

Tobacco Road Sand 

1. Eocene, late 

2. Georgia (EC) 

3. Huddlestun, P. F., and Hetrick, J. H., 1978, Stratigraphy of 

the Tobacco Road Sand--a new formation: Georgia Geol. 

Survey Bull. 93, p. 56-77 

4. Sand with minor chert and limestone 

5. Greenish-gray, weathers red 

6. 8.5 m, range 3-8.5 m 7. Medium- to coarse-grained, fossiliferous, coastal marine 

deposits 

8. Sandersville Limestone Member at base 

9. Gradationally or disconformably overlies Irwinton Sand or 

Twiggs Clay; disconformably underlies Hawthorn(?) Formation 

or undivided Tertiary and Quaternary deposits. Unit was 

former unnamed upper sand member of Barnwell Formation 

10. Type locality: E side of Morgan Road, 0.5 km N of junction 

of Morgan Road and Tobacco Road, Richmond County, Ga. 

Tobinsport Formation (Buffalo Wallow Group) 

1. Late Mississippian (Chesterian) 

2. Indiana (SC) 

3. Gray, H. H., 1978, Buffalo Wallow Group--upper Chesterian 

(Mississippian) of southern Indiana: Indiana Geol. Survey 

Occasional Paper 25, p. 10-13 

4. Shale with interbedded sandstone and limestone 

6. 38 m, range 27-38 m 

8. Siberia Limestone Member, Bristow Sandstone Member, Mount 

Pleasant Sandstone Member, Negli Creek Limestone Member; 

interbedded with unnamed shale beds of Tobinsport Formation 

9. Conformably overlies Leopold Limestone Member (Branchville 

Formation); unconformably underlies Mansfield Formation 

10. Type section: Peach Hill Section, NW/14 sec. 34 and SW/14 sec. 27, T. 7 s., R. 2 W., Perry County, Ind. Named for 

town of Tobinsport. 

Togiak Basalt 

1. Quaternary 
174 

2. 

3. 

4. 

5. 

6. 

7. 

B. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Alaska (C) 

Hoare, J. M., and Coonrad, W. L., 1980, The Togiak Basalt, a 

new formation in southwestern Alaska:' U.S. Geol. Survey 

Bull. 1482-C, p. C1-C11 

Tholeiite, alkali-olivine basalt 

Gray, black 

<20 m 

Forms glassy and medium-grained flows and prominent butte; 

columnar jointing; pillow lava; subglacial tuya deposit 

Unnamed lower and upper parts 

Unconformably overlies iron-stained sand and gravel and 

Mesozoic sedimentary and volcanic rocks; underlies glacial 

deposits 

Type section: Exposures on sea cliff E of Togiak Bay, SW1/4 sec. 1, T. 15 S., R. 66 W., Hagemeister Island D-1 quadrangle, Bristol Bay area, Alaska. Named for Togiak River 

and Togiak Bay. 

Tomany Mountain Formation 

1. Proterozoic 

2. New York (C) 

3. McLelland, James, and Isachsen, Yngvar, 1980, Structural 

synthesis of the southern and central Adirondacks--a model 

for the Adirondacks as a whole and plate tectonics interpretations: Geol. Soc. America Bull. (pt. 2, microfiche), v. 

91, no. 2, p. 224-225 

4. Kinzigite (sillimanite-garnet-biotite-quartz-oligoclase 

gneiss), quartzite, leucogneiss, minor amphibolite 

6. Range 300-1,000 m 9. Overlies Lake Durant Formation; underlies Rooster Hill Megacrystic Gneiss 

10. Type locality: Tomany Mountain, SW of Averys Place on New 

York Route 10, Piseco Lake quadrangle, Hamilton County, N.Y. 

Tonopah Summit Member (Fraction Tuff) 

1. Miocene 

2. Nevada (C) 

3. Bonham, H. F., Jr., and Garside, L. J., 1979, Geology of the 

Tonopah, Lone Mountain, Klondike, and northern Mud Lake 

quadrangles, Nevada: Nevada Bur. Mines and Geology Bull. 

92, p. 50-51 

4. Vitric-lithic quartz latite to rhyolite ash-flow tuff 

6. Range 60-400 m 

7. Nonwelded to weakly welded, hydrothermally altered, in part 

9. Unconformably overlies Mizpah Formation; unconformably 

underlies Siebert Formation, Heller Tuff, King Tonopah 

Member (Fraction Tuff), and trachyandesite of Red Mountain; 

intruded by Oddie Rhyolite; intruded and overlain by 

Brougher Rhyolite 

10. Type locality: Low slopes S and SE of Mount Butler and 

Brock Mountain, sees. 11 and 12, T. 2 N., R. 42 E., near Tonopah Summit, 1.6 km SE of town of Tonopah, Esmeralda 

County, Nev. 

Tony Grove Lake Member (Laketown Dolostone) 

1. Early Silurian 

2. Utah (NC), Nevada 

3. Budge, D. R., and Sheehan, P. H., 1980, The Upper Ordovician 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 175 

through Middle Silurian of the eastern Great Basin--Pt. 1, 

Introduction--historical perspective and stratigraphic 

synthesis; Pt. 2, Lithologic descriptions: Milwaukee Public 

Mus. Contr. Biology and Geology, no. 28, p. 19 (pt. 1); 

no. 29, p. 6-7 (pt. 2) 

4. Dolomite with interbedded conglomerate 

5. Light-gray, grayish-black, weathers gray 

6. 190 m 

7. Microcrystalline to finely crystalline, thin- to thickbedded, banded 

9. Overlies informal Bloomington Lake Member (Fish Haven 

Dolostone); underlies High Lake Member (Laketown Dolostone) 

10. Type section: SW1/4SW1/4 sec. 5, T. 13 N., R. 3 E., Tony 

Grove Lake, Bear River Range, Cache County, Utah. 

Topanga Canyon Formation (Topanga Group) 

1. Miocene, middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E14-E17 

4. Biotitic sandstone, siltstone, and pebbly sandstone 

6. 675 m where undivided 

7. Marine, nearshore marine, and nonmarine facies 

8. Undivided between Trancas and Malibu Canyons; W of Trancas 

Canyon: Encinal Member; E of Malibu Canyon: Saddle Peak, 

Fernwood, and Cold Creek Members 

9. Conformably overlies Vaqueros Formation or Sespe Formation; 

underlies Conejo Volcanics (Topanga Group) or, locally, 

Calabasas Formation (Topanga Group) 

10. Type locality: "Topanga Canyon fauna" locality, roadcuts on 

Old Topanga Road, SW1/4 sec. 35, T. 1 N., R. 17 W., Santa 

Monica Mountains, NE corner Malibu Beach quadrangle, Los 

Angeles County, Calif. Named for Topanga Canyon, which is 

SE of type locality. 

Topbet Swamp Gneiss Member (Nashoba Formation) 

1. pre-Silurian 

2. Massachusetts (C) 

3. Bell, K. G., and Alvord, D. C., 1976, Pre-Silurian stratigraphy of northeastern Massachusetts: Geol. Soc. America 

Mem. 148, p. 186-187, 208, app. 1 (in pocket) 

4. Sillimanitic biotite gneiss 

5. Medium-gray 

6. 920 m 

7. Medium-grained, stratified, relict sedimentary structures 

9. Overlies Spencer Brook Member; underlies Nashoba Brook 

Member 

10. Type locality: Tophet Swamp in town of Carlisle, Billerica 

quadrangle, Middlesex County, Mass. 

Torquay 

1 • 

2. 

3. 

Formation (Three Forks Group) 

Late Devonian 

Canada (Saskatchewan), Montana, North Dakota 

Christopher, J. E., 1961, Transitional DevonianMississippian formations of southern Saskatchewan: 

Saskatchewan Dept. Mineral Resources Rept. 66, p. 15-23 
176 

4. 

5. 

6. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Dolomite, shale, and minor anhydrite in alternating 

laminated and massive units 

Banded and mottled gray, brown, green, white 

52 m 

Conformably overlies Birdbear Formation; disconformably 

underlies Bakken Formation in SE Saskatchewan and NW North 

Dakota; underlies intervening Big Valley Formation in SW 

Saskatchewan and NC Montana 

Type section: Compagnie Francaise des Petroles, Torquay 

No. 1 well, depth-interval 2,010-2,062 m, Lsd. 8-32-3-11w2, 

SE Saskatchewan, Canada. Named for town of Torquay. 

Towaco Formation (Newark Supergroup) 

1. Early Jurassic 

2. New Jersey (NE) 

3. Olsen, P. E., 1980, The latest Triassic and Early Jurassic 

formations of the Newark Basin (eastern North America, 

Newark Supergroup)--stratigraphy, structure, and correlation: New Jersey Acad. Sci. Bull., v. 25, no. 2, p. 36-37 

4. Microlaminated calcareous siltstone underlain and overlain 

by sandstone and siltstone beds and red clastics arranged in 

fining-upwards cycles 

5. Black, gray, red 

6. 60 m 7. Symmetrical sedimentary cyclic deposits 

9. Overlies Preakness Basalt; underlies Hook Mountain Basalt. 

Unit was formerly a subdivision of upper part of Brunswick 

Formation of Kummel (1897) 

10. Type section: Essex County Park Commission Dinosaur Tract, 

Roseland quarry, Roseland, 12 km S of village of Towaco, 

Essex County, N.J. 

Toxaway Gneiss 

1. Precambrian 

2. North Carolina (WC), South Carolina 

3. Hatcher, R. D., Jr., 1977, Macroscopic polyphase folding 

illustrated by the Toxaway dome, eastern Blue Ridge, South 

Carolina-North Carolina: Geol. Soc. America Bull., v. 88, 

no. 11, p. 1678-1679 

4. Granitic to quartz monzonitic gneiss 

7. Banded, forms core of Toxaway structural dome, folded 

repeatedly 

B. Previously named Whiteside Granite 

9. Base not exposed; unconformably underlies Tallulah Falls 

Formation 

10. Type locality: Exposures at Toxaway Falls on Toxaway River 

near Lake Toxaway, Transylvania County, N.C. 

Trancas Fonaation 

1. Miocene, early and middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, 

nomenclature of the central 

Angeles County, California: 

p. E25-E27 

R. H., 1979, Stratigraphic 

Santa Monica Mountains, Los 

U.S. Geol. Survey Bull. 1457-E, 

4. Sandstone, mudstone, shale, claystone, sedimentary breccia 

6. 290 m 7. Intensely folded and faulted, marine, locally fossiliferous 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 177 

9. Base not exposed in mapped area; inferred to unconformably 

overlie Catalina Schist; intertongues with Zuma Volcanics; 

unconformably underlies and intertongues with Monterey Shale 

10. Type locality: Exposures near mouth of Trancas Canyon, 

Santa Monica Mountains, SW Point Dume quadrangle, Los 

Angeles County, Calif. 

Treadwell Member (Clinchfield Formation) 

1. Eocene, late 

2. Georgia (C) 

3. Huddlestun, P. F., and Hetrick, J. H., 1979, The stratigraphy or the Barnwell Group of Georgia: Georgia Geol. 

Survey Open File Rept. 80-1, p. 12-13, 76-78 

4. Calcareous sand to sandy limestone 

6. 4.1 m 

7. Hard limestone and sandstone form ledges between less indurated sand beds; fossiliferous 

9. Gradationally overlies Riggins Mill Member (Clinchfield 

Formation); gradationally underlies Tivola Limestone (Ocala 

Group) 

10. Type locality: Georgia Kaolin Company Pit 50, 1.2 km SW of 

Riggins Mill Road and community of Treadwell, 2.24 km SE of 

Bibb-Twiggs County line, Twiggs County, Ga. 

Tuckerton Member (Allentown Formation) 

1. Late Cambrian 

2. Pennsylvania (SE) 

3. MacLachlan, o: B., 1979, Geology and mineral resources of 

the Temple and Fleetwood quadrangles, Berks County, Pennsylvania: Pennsylvania Geol. Survey, 4th ser., Atlas 187ab, p. 

14-15 

4. Limestone, dolomite, chert 

5. Light-gray 

6. Range 150-180 m 

1. Stromatolitic, oolitic, cyclic deposits 

9. Transitionally overlies Leithsville Formation; conformably 

underlies Muhlenberg Member (Allentown Formation) 

10. Type area: Village of Tuckerton on Pennsylvania Route 61, 

Temple quadrangle, Berks County, Pa. 

Tuna Canyon Formation 

1. Late Cretaceous 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E4-E7 

4. Arkosic sandstone 

6. 800 m 

1. Thick-bedded, graded, laminated, coarse-grained turbidite, 

fossiliferous 

9. Base not exposed in mapped area; inferred, from exposures to 

NE, to overlie Santa Monica Slate or Late Cretaceous 

conglomerate; disconformably(?) underlies Coal Canyon 

Formation or, locally, intervening Simi(?) Conglomerate 

10. Type locality: Tuna Canyon, sec. 30, T. 1 S., R. 16 W., 

Santa Monica Mountains, WC Topanga quadrangle, Los Angeles 

County, Calif. 
178 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Twin Spruce Quartz MOnzonite 

1. Early Proterozoic 

2. Colorado (NC) 

3. Gable, D. J., 1980, The Boulder Creek batholith, Front 

Range, Colorado: U.S. Geol. Survey Prof. Paper 1101, 

p. 26-35 

4. Quartz monzonite, ranges to granite 

5. Gray, orange-brown when weathered 

7. Fine-grained; breaks into slabby layers that obscure 

contacts 

9. Occupies nearly a quarter of Boulder Creek batholith and is 

slightly younger than Bould~r. Creek Granodiorite 

10. Type locality: Just NE of settlement of Twin Spruce where 

typical quartz monzonite crops out in Coal Creek Canyon, 

Eldorado Springs quadrangle, Boulder County, Colo. 

Underwood Mudflow Breccia 

1. Miocene, early and middle 

2. California (C) 

3. Axelrod, D. I., 1980, Contributions to the Neogene paleobotany of central California: California Univ. Pubs. Geol. 

Sci., v. 121, p. 22 

4. Hypersthene and augite mudflow breccia 

5. Dark-brown to black 

6. 60 m 

7. Massive, poorly bedded 

9. Overlies granitic basement rocks or interfingers with Bear 

Valley Formation; underlies Relief Peak Formation 

10. Type location: Ridges that form E and W walls of Underwood 

Valley, Alpine County, Calif. 

Ursus Member (Kamishak Formation) 

1. Late Triassic 

2. Alaska (C) 

3. Detterman, R. L., and Reed, B. L., 1980, Stratigraphy, 

structure, and economic geology of the Iliamna quadrangle, 

Alaska: U.S. Geol. Survey Bull. 1368-B, p. B16-B17 

4. Limestone, locally dolomitic, with interbedded chert and 

tuff 

5. Light-gray 

6. >150 m 

7. Thin-bedded, fossil fragments; cut by mafic dikes 

9. Gradationally overlies unnamed middle member of Kamishak 

Formation; disconformably underlies Talkeetna Formation; 

intruded by Jurassic rocks of Alaska-Aleutian Range batholith 

10. Type section: Exposures on S side of Brown Peak, N of Ursus 

Cove, Cook Inlet, Iliamna quadrangle, Alaska Peninsula, 

Alaska. 

Utley Limestone Member (Clinchfield Formation) 

1. Eocene, late 

2. Georgia (EC) 

3. Huddlestun, P. F., and Hetrick, J. H., 1979, The stratigraphy of the Barnwell Group of Georgia: Georgia Geol. 

Survey Open File Rept. 80-1, p. 16-17, 54 

4. Sandy, glauconitic limestone 

6. 4 m (in Burke no. 3 (GGS-1172) core at Griffins Landing) 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 179 

7. Cavernous, fossiliferous; patchy distribution due to deposition in topographic lows or to solution 

9. Unconformably overlies Lisbon Formation; underlies Dry 

Branch Formation (Barnwell Group) 

10. Type locality: Utleys Cave at upper end of Mallard Pond, on 

property of Georgia Power Co. Plant Vogtle site, 2.1 km SE 

of intersection of Hancock Landing Road and River Road, 

Burke County, Ga. 

Vagner Formation (Deep Lake Group) 

1. Early Proterozoic 

2. Wyoming (SE) 

3. Karlstrom, K. E., and Houston, R. s., 1979, Stratigraphy and 

uranium potential of Early Proterozoic metasedimentary rocks 

in the Medicine Bow Mountains, Wyoming: Wyoming Geol. 

Survey Rept. Inv. 13, p. 19-20, 44 / 

4. Paraconglomerate, marble, phyllite 

6. Range 120-400 m 7. Possibly glaciomarine deposits 

9. Unconformably overlies Cascade Quartzite; underlies Rock 

Knoll Formation 

10. Type section: W of Vagner Lake, SW1/4 sec. 1, T. 16 N., 

R. 79 [80] W., Medicine Bow Mountains, Carbon County, Wyo. 

Van Buskirk Gneiss 

1. Precambrian, early [Late Archean] 

2. Michigan (NW) 

3. Schmidt, R. G., 1976, Geology of the Precambrian W (lower 

Precambrian) rocks in western Gogebic County, Michigan: 

U.S. Geol. Survey Bull. 1407, p. 14-26 

4. Gneiss consisting of interlayered quartz diorite and quartz 

monzonite 

5. Dark- and light-colored banded layers 

7. Generally layered, foliated, migmatitic 

9. Grades northward into Puritan Quartz Monzonite within 

Puritan-Van Buskirk pluton 

10. Type locality: Exposures in parts of sees. 12 and 13, 

T. 46 N., R. 47 W., Gogebic County, Mich., near community of 

Van Buskirk, Iron County, Wis. 

Vicks Peak Rhyolite 

1. Oligocene 

2. New Mexico (WC) 

3. Deal, E. G., and Rhodes, R. C., 1976, Volcano-tectonic 

structures in the San Mateo Mountains, Socorro County, New 

Mexico: New Mexico Geol. Soc. Spec. Pub. 5, p. 52-53 

4. Rhyolite ash-flow tuff, crystal-poor 

5. Gray to purple 

6. 650 m, range 200-650 m 7. Moderately to densely welded; major ash-flow sheet erupted 

from Nogal Canyon cauldron 

9. Overlies Rock Spring Formation; conformably underlies 

Springtime Canyon Quartz Latite 

10. Type locality: Vicks Peak, S San Mateo Mountains, Socorro 

County, N. Mex. 

Waikahalulu Formation (Laupahoehoe Group) 

1. Pleistocene and Holocene 
180 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Hawaii (SC) 

Porter, S. C., 1979, Quaternary stratigraphy and chronology 

of Mauna Kea, Hawaii--a 380,000-yr record of mid-Pacific 

volcanism and ice-cap glaciation: Geol. Soc. America Bull. 

(pt. 2, microfiche), v. 90, no. 7, p. 1024-1041 

Alkalic hawaiite lavas and pyroclastic cinder cones and 

tephra layers 

Range <30->100 m for lava flows 

Long clinkery aa flows and lava domes around vents 

Unconformably overlies Hopukani and Pohakuloa Formations 

(Hamakua Group); interstratified with Waihu and Makanaka 

Formations (Laupahoehoe Group) 

Type section: Upper Waikahalulu Gulch where W rim of gulch 

ranges between 2,985 and 3,350 malt., Mauna Kea volcano, 

Hawaii County, Hawaii. 

Wallace 

1. 

2. 

3. 

Creek Shale Member (Marcella Formation) 

Late Mississippian 

Arkansas (NC) 

Ogren, D. E., 1968, Stratigraphy of Upper Mississippian 

rocks of northern Arkansas: Am. Assoc. Petroleum Geologists 

Bull., v. 52, no. 2, p. 282-292 

4. 

5. 

6. 

7. 

9. 

10. 

Carbonaceous, siliceous shale 

Black 

18 m, range <1-18 m 

Weathers to hard, brittle blocks 

Conformably overlies Pitkin Limestone; basal unit of 

Marcella Formation 

Type section: Exposure along intermittent tributary of 

Wallace Creek, NW1/4 sec. 12, T. 13 N., R. 9 W., near 

Marcella, Stone County, Ark. 

Wallsburg Ridge Member (Oquirrh Formation) 

1. Late Pennsylvanian (Missourian to Virgilian) 

2. Utah (C) 

3. Baker, A. A., 1976, Geologic map of the west half of the 

Strawberry Valley quadrangle, Utah: U.S. Geol. Survey Misc. 

Inv. Ser. Map I-931, p. 2 

4. Quartzite interbedded with limy sandstone and cherty limestone 

5. Light-gray, red, blue-gray 

6. 2,400 m 7. Fine- to medium-grained; in part finely laminated; fossiliferous (fusulinids) 

9. Overlies Shingle Mill Limestone Member; underlies Granger 

Mountain Member 

10. Type locality: Outcrop along crest of Wallsburg Ridge, 

approximately from Strawberry Valley quadrangle line E to 

SE1/4 sec. 27, T. 5 s., R. 4 E., Utah.County, Utah. 

Vanapum Basalt (Yakima Basalt Subgroup of Columbia River Basalt Group) 

1. Miocene, middle 

2. Washington (C), Oregon, Idaho 

3. Swanson, D. A., and others, 1979, Revisions in stratigraphic 

nomenclature of the Columbia River Basalt Group: U.S. Geol. 

Survey Bull. 1457-G, p. G25-G37 

4. Olivine- and plagioclase-phyric basalt 

6. 120 m 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

7. Medium-grained flows 

8. Eckler Mountain, Frenchman Springs, Roza, and Priest Rapids 

Members 

181 

9. Conformably and disconformably overlies Grande Ronde Basalt 

(Yakima Basalt Subgroup) or overlies Vantage Member (Ellensburg Formation); generally conformably underlies Saddle 

Mountains Basalt (Yakima Basalt Subgroup) 

10. Type locality: Exposures along E side of Columbia River near Wanapum Dam, from Sand Hollow in sec. 28, T. 17 N., 

R. 23 E., S to top of section near Vantage Substation above 

Wanapum Dam in sec. 16, T. 16 N., R. 23 E., Vantage and 

Beverly quadrangles, Grant County, Wash. 

Ward Siltstone Member (Fort Cassin Formation) 

1. Early Ordovician 

2. New York (NE), Vermont 

3. Fisher, D. W., 1977, Correlation of the Hadrynian, Cambrian 

and Ordovician rocks in New York State: New York State Mus. 

Map and Chart Ser., no. 25, p. 64 

4. Calcitic and dolomitic siltstone 

5. Bluish-gray, weathers tan 

6. Range <1-29 m 

7. Thin-bedded, laminated, cross-laminated 

9. Overlies Fort Ann Formation; transitionally underlies Sciota 

Limestone Member (Fort Cassin Formation) 

10. Type locality: Near Ward Farm, along Washington County 

Route 10, 7.1 km NNE of intersection of U.S. Highway 4 and 

New York Highway 22 in Whitehall, Thorn Hill quadrangle, 

Washington County, N.Y. Named for Ward Marsh, S of Ward 

Farm. 

Warner Hill Limestone Member (Whitehall Formation) 

1. Late Cambrian 

2. New York (NE) 

3. Fisher, D. W., 1977, Correlation of the Hadrynian, Cambrian 

and Ordovician rocks in New York State: New York State Mus. 

Map and Chart Ser., no. 25, p. 51 

4. Calcilutite limestone with chert beds 

5. Light-gray 

6. 27.5 m, range 3-27.5 m 

7. Massive-bedded, stromatolite mounds 

9. Overlies Finch Dolostone Member; gradationally underlies 

Skene Dolostone Member 

10. Type locality: Abandoned quarry on N side of Washington 

County Route 10, 3.2 km NE of intersection of U.S. Highway 4 

and New York Highway 22 in Whitehall, Whitehall quadrangle, 

Washington County, N.Y. Named for Warner Hill, 1.6 km N of 

type locality. 

Warrensville Till 

1. Pleistocene (early Wisconsinan) 

2. Pennsylvania (C) 

3. Wells, R. B., and Bucek, M. F., 1980, Geology and mineral resources of the Montoursville North and Huntersville quadrangles, Lycoming County, Pennsylvania: Pennsylvania 

Geological Survey, 4th ser., Atlas 143cd, p. 24, 30, 62 

4. Noncalcareous till consisting of clay, silt, sand, pebbles, 

and cobbles 
182 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

5. Reddish-brown or weak red 

6. 30.48 m 

7. Unconsolidated, nonstratified, well compacted 

9. Overlies Warrensville drift and Muncy Till; underlies Olean 

Till 

10. Type section: Along road connecting Warrensville and U.S. 

Highway 220, 6.4 km S of Warrensville and approximately 0.5 

km NE of Edgewood Cemetery, W of Williamsport, lat 41°15'17" 

N., long 76°56' 15" W., Montoursville North quadrangle, 

Lycoming County, Pa. 

Watab Amphibolite (Sauk Rapids Metamorphic Complex) 

1. Precambrian, early 

2. Minnesota (C) 

3. Morey, G. B., 1978, Lower and middle Precambrian stratigraphic nomenclature for east-central Minnesota: Minnesota 

Geol. Survey Rept. Inv. 21, p. 10-11 

4. Hornblende-pyroxene-plagioclase gneiss 

5. Black to greenish-black 

7. Vaguely foliated, E-trending lenticular mass 3 km wide and 5 

km long 

9. Interlayered to NW with Sartell Gneiss (Sauk Rapids Metamorphic Complex); truncated on SE by intrusive Stearns Granitic 

Complex 

10. Type locality: Abandoned quarry 1 km S of village of Watab, 

T. 37 N., R. 30 W., Watab Township, Benton County, Minn. 

Waterfall 

1. 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

Formation 

Early Jurassic 

Virginia (NE) 

Lindholm, R. c., 1979, Geologic history and stratigraphy of 

the Triassic-Jurassic Culpeper Basin, Virginia: Geol. Soc. 

America Bull. (pts. 1 and 2), v. 90, no. 11, p. 997 (pt. 1, 

summary); p. 1725-1732 (pt. 2, microfiche) 

Interbedded silicate and quartzite conglomerate, sandstone, 

and shale 

1,500 m 

Fish-bearing lacustrine black calcareous shale beds in upper 

part 

Overlies Buckland Formation; in normal-fault contact with 

older rocks of Blue Ridge on W margin of Culpeper basin 

Type locality: Exposures in fields NW of community of 

Waterfall, Culpeper basin, Prince William County, Va. 

Waterford Group 

1. Late Proterozoic 

2. Connecticut (SE) 

3. Goldsmith, Richard, 1980, Stratigraphic names in the New 

London area, southeastern Connecticut--a revision: U.S. 

Geol. Survey Bull. 1502-A, p. A96-A99 

4. Plagioclase-rich quartz-dioritic and granodioritic gneisses, 

amphibolite 

5. Gray 

6. 3,100 m max 7. Layered, massive 

8. Mamacoke Formation, New London Gneiss with its lower Joshua 

Rock Gneiss Member and upper unnamed granodiorite gneiss 

member, Rope Ferry Gneiss 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 183 

9. Overlies Plainfield Formation; underlies Quinebaug Formation 

or schist in Hunts Brook 

10. Type area: Exposures in town of Waterford, New London 

County, Conn. 

Waukon Member (Jordan Formation) 

1. Late Cambrian 

2. Iowa (NE), Wisconsin 

3. Odom, I. E., and Ostrom, M. E., 1978, Lithostratigraphy, 

petrology, sedimentology, and depositional environments of 

the Jordan Formation near Madison, Wisconsin: Soc. Econ. 

Paleontologists and Mineralogists, Great Lakes Sec., 8th 

Ann. Mtg., Guidebook 3, p. 26, 29 

4. Slightly dolomitic feldspathic sandstone 

6. 5.5 m 7. Very fine grained, massive to thin-bedded, bioturbated 

9. Intertongues with Van Oser Member (Jordan Formation), which 

underlies and overlies it 

10. Type section: N side of Upper Iowa River on Iowa State Road 

26A, 1.62 km E of Iowa Highway 76 and 16 km N of Waukon, 

Allamakee County, Iowa. 

Weatherby 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

Formation 

Early and Middle Jurassic 

Oregon (EC), Idaho 

Brooks, H. C., 1979, Geologic map of the Huntington and part 

of the Olds ~erry quadrangles, Baker and Malheur Counties, 

Oregon: Oregon Dept. Geology and Mineral Industries Geol. 

Map Ser. GMS-13 

Wacke, siltstone, argillite; less abundant phyllite, slate, 

conglomerate, limestone 

Tan, light-gray, olive-green 

<7,000 m Pervasive shear cleavage obscures bedding features in most 

exposures; fossiliferous (ammonites) 

Jet Creek Member 

Unconformably overlies Huntington Formation; fault contact 

with unnamed Paleozoic and Triassic rocks 

Type section: Exposures along Snake River road, Tps. 12 and 

13 S., R. 45 E., Baker County, Oreg. Named for Weatherby, a 

railroad siding in canyon of Burnt River, sec. 30, T. 12 S., 

R. 44 E., Baker County, Oreg. 

Weed Heights Member (Mickey Pass Tuff) 

1. Oligocene 

2. Nevada (WC) 

3. Proffett, J. M., Jr., and Proffett, B. H., 1976, Stratigraphy of the Tertiary ash-flow tuffs in the Yerington 

district, Nevada: Nevada Bur. Mines and Geology Rept. 27, 

p. 17-19 

4. Silicic dacite, quartz latite, and rhyolite ash-flow tuff, 

with basal vitrophyre 

5. Buff, lavender, reddish-brown 

6. 120 m, range 30-180 m 7. Moderately welded, crystal-rich cooling unit; prominent 

ridge former 

9. Overlies Guild Mine Member or intervening unnamed map units 

4 or 5 of Mickey Pass Tuff; underlies Singatse Tuff or 
184 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

intervening unnamed map unit 7 at top of Mickey Pass Tuff 

Type area: Exposures 0.8 km SW of Weed Heights, Singatse 

Range, Lyon County, Nev. 

Veissenfels Ridge Member (Saddle Mountains Basalt) 

1. Miocene, middle 

2. Washington (SE), Idaho 

3. Swanson, D. A., and others, 1979, Revisions in stratigraphic 

nomenclature of the Columbia River Basalt Group: U.S. Geol. 

Survey Bull. 1457-G, p. G44-G45 

4. Olivine basalt, sparsely to moderately plagioclase-phyric 

6. 34 m, range <10-37 m 

7. Coarse-grained, three or more flows 

8. Informal basalt of Lewiston Orchards and basalt of Slippery 

Creek 

9. Overlies sandstone and basaltic conglomerate above Asotin 

Member; unconformably underlies Elephant Mountain Member 

10. Type locality: Roadcuts along Weissenfels Ridge, NW1/4 

sec. 24 and NE1/4 sec. 23, T. 9 N., R. 46 E., Captain John 

Rapids quadrangle, Asotin County, Wash. 

Welling 

1 • 

2. 

3. 

Formation 

4. 

6. 

7. 

9. 

10. 

West Bath 

1. 

2. 

3. 

4. 

5. 

7. 

9. 

10. 

Late Ordovician 

Oklahoma (EC) 

Amsden, T. W., 1979, Welling Formation, new name for 

Ordovician unit in eastern Oklahoma (formerly called 

"Fernvale"): Am. Assoc. Petroleum Geologists Bull., 

no. 7, p. 1135-1138 

Low-magnesium, organic-detrital limestone with minor 

detrital quartz 

6 m, range 6-15 m 

Upper 

v. 63, 

Obscurely bedded, abundant fossil debris, widely distributed 

marker bed in subsurface 

Replaces the name "Fernvale Limestone" in E Oklahoma. Overlies Fite Formation; underlies Sylvan Shale 

Type section: W bluff of Illinois River at Horseshoe Bend, 

NE1/4NE1/4 sec. 36, T. 16 N., R. 22 E., 13 km S of Tahlequah 

and 5.2 km S of Welling, Cherokee County, Okla. 

Member (Ammonoosuc Formation) 

Middle Ordovician 

New Hampshire (WC) 

Prager, G. D., 1980, Stratigraphy of the Gardner Mountain 

area, New Hampshire: Northeastern Geology, v. 2, no. 1, 

p. 34 

Calcareous schist 

Blue-gray 

Well-foliated, irregular cleavage surfaces which impart a 

lumpy appearance; weathers easily 

Overlies Mullikin Brook Member; underlies Smutty Hollow or Lyman Member (Ammonoosuc Formation) 

Type locality: Hillside 2.4 km SSW of old West Bath School 

site, Grafton County, N.H. 

West Fargo Member (Poplar River Formation) 

1. Pleistocene (Wisconsinan) 

2. Minnesota (WC), North Dakota 

3. Arndt, B. M., 1977, Stratigraphy of offshore sediment, Lake 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Agassiz--North Dakota: North Dakota Geol. Survey Rept. 

Inv. 60, p. 6-8 

4. Silt, clayey silt, peat 

5. Dark-gray 

6. 5.5 m 

7. Laminated; organic laminae; fluvial deposits 

185 

9. Unconformably overlies Brenna Formation or conformably overlies Harwood Member (Poplar River Formation); gradationally 

underlies Sherack Formation) 

10. Type section: Composite borings 1, 2, and 3, F-2 Dormitory, 

Moorhead State College, SE1/4NE1/4SE1/4 sec. 8, T. 139 N., 

R. 48 W., Moorhead, Clay County, Minn. Type area: Vicinity 

of Fargo, N. Dak. Named for town of West Fargo, Cass 

County. 

Whiskers Creek Gneiss 

1. Precambrian, early [Late Archean] 

2. Michigan (NW) 

3. Schmidt, R. G., 1976, Geology of the Precambrian W (lower 

Precambrian) rocks in western Gogebic County, Michigan: 

U.S. Geol. Survey Bull. 1407, p. 8-14 

4. Granodioritic gneiss, hornblendic metaconglomerate locally 

7. Slightly foliated, derived from Ramsay Formation by contact 

metamorphism 

9. Grades into Ramsay Formation away from Puritan Quartz Monzonite, which intrudes them; to N, unconformably underlies 

early Precambrian strata 

10. Type area: Outcrops near Anvil and Ramsay, and in area 

extending about 3 km SE of Ironwood, including area along 

Whiskers Creek, T. 46 N., R. 47 W., Gogebic County, Mich. 

Whiskey Butte Bed (Bridger Formation) 

1. Eocene 

2. Wyoming (SW) 

3. Sullivan, Raymond, 1980, A stratigraphic evaluation of the 

Eocene rocks of southwestern Wyoming: Wyoming Geol. Survey 

Rept. Inv. 20, p. 40-41 

4. Siltstone, mudstone, claystone 

5. Gray to greenish 

6. 70 m max 

7. Fluvial unit at base of Bridger Formation along W margin of 

Green River Basin. 

9. Separated from main part of Bridger Formation by intertonguing Cow Hollow Bed (Laney Member of Green River Formation); overlies and intertongues with Craven Creek Bed 

(Laney Member of Green River Formation) 

10. Type locality: Exposures in T. 21 N., R. 111 W., Whiskey 

Butte quadrangle, Lincoln County, Wyo. 

Vbite Throne Member (Temple Cap Sandstone) 

1. Middle Jurassic 

2. Utah (SW) 

3. Peterson, Fred, and Pipiringos, G. N., 1979, Stratigraphic 

relations of the Navajo Sandstone to Middle Jurassic formations in parts of southern Utah and northern Arizona: U.S. 

Geol. Survey Prof. Paper 1035-B, p. B9-B10 

4. Sandstone 

5. Gray to orange 
186 

6. 

7. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

49.7 m, range <1-49.7 m 

Fine-grained, crossbedded, cliff-forming 

Overlies Sinawava Member (Temple Cap Sandstone); unconformably underlies Carmel Formation (San Rafael Group) 

Type section: At top of Zion Canyon about 500 m NE of 

Observation Point, NW1/4NW1/4 sec. 2, T. 41 s., R. 10 W., 

Zion National Park, Washington County, Utah. Named for 

Great White Throne in Zion Canyon, 2 km S of type section. 

Wilbur Creek Member (Saddle Mountains Basalt) 

1. Miocene, middle 

2. Washington (SE), Idaho 

3. Swanson, D. A., and others, 1979, Revisions in stratigraphic 

nomenclature of the Columbia River Basalt Group: U.S. Geol. 

Survey Bull. 1457-G, p. G42 

4. Sparsely plagioclase-phyric basalt 

6. Range <20->45 m 

7. Fine-grained 

9. Conformably overlies Umatilla Member (Saddle Mountains 

Basalt) or unconformably overlies Priest Rapids Member 

(Wanapum Basalt); unconformably underlies Asotin Member 

(Saddle Mountains Basalt) (both formations in Yakima Basalt 

Subgroup of Columbia River Basalt Group) 

10. Type locality: Roadcuts along Wilbur Creek, sec. 9 and 

SW1/4SW1/4 sec. 4, T. 14 N., R. 44 E., 7 km W of Pullman, 

Ewartsville quadrangle, Whitman County, Wash. 

Vild Sheep Creek Formation (Seven Devils Group) 

1. Middle and Late Triassic 

2. Oregon (NE), Idaho 

3. Vallier, T. L., 1977, The Permian and Triassic Seven Devils 

Group, western Idaho and northwestern Oregon: U.S. Geol. 

Survey Bull. 1437, p. 27-36 

4. Metamorphosed basalt, basaltic andesite, and andesite flows 

and volcaniclastic graywacke, argillite, and limestone 

5. Dark-green, greenish-black 

6. 830 m, range 440-2,500 m 

7. Rugged outcrops, pillow lavas, massive flows 

9. Unconformably overlies Hunsaker Creek Formation; conformably 

underlies Doyle Creek Formation 

10. Type section: Spur between Saddle and Hat Creeks, 425-900 m 

elevation, across Snake River from NE1/4 sec. 30, T. 24 N., 

R. 2 W. (in Adams County, Idaho), He-Devil quadrangle, 

Wallowa County, Oreg. Named for nearby Wild Sheep Creek~ 

Wilkie Ranch Formation 

1. Early Permian (Leonardian) 

2. Texas (WC) 

3. Cys, J. M., 1976, Wilkie Ranch Formation, new Permian unit 

in Finlay Mountains: Am. Assoc. Petroleum Geologists Bull., 

v. 60, no. 7, p. 1107-1110 

4. Interbedded marlstone, limestone, and limestone conglomerate 

5. Gray 

6. Range 511-533 m· 7. Fossiliferous 

9. Unconformably overlies Hueco Limestone; unconformably underlies Campagrande Formation 

10. Type section: Measured Section 1 of Albritton, C. C., Jr., 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

and Smith, J. F., Jr., 1965, U.S. Geol. Survey Prof. Paper 

479, p. 8-9, and Gulf 1 Burner-State "B" well, depthinterval 0-70 m, W Finlay Mountains, Hudspeth County, Tex. 

Named for nearby Wilkie Ranch. 

Wilson Ridge Formation (Chilhowee Group) 

1. Early Cambrian 

2. Alabama (NE), Georgia 

3. Mack, G. H., 1980, Stratigraphy and depositional environments of the Chilhowee Group (Cambrian) in Georgia and 

Alabama: Am. Jour. Sci., v. 280, no. 6, p. 503, 514-515 

4. Sandstone (orthoquartzite) facies interbedded with silty 

mudstone facies 

5. Gray 

6. 184 m, range 10-425 m 

187 

7. Tidal-flat deposits; crossbedded sandstone, ripple-laminated 

mudstone 

9. Transitionally overlies Nichols Shale; conformably underlies 

Weisner Formation with sharp contact 

10. Type section: Exposure on NE side of Cleburne County 

Highway 70, between Piedmont and Borden Springs, NE1/4NE1/4 

sec. 5, T. 13 S., R. 11 E., Cleburne County, Ala. Readout 

bisects Wilson Ridge. 

Winchell Creek Siltstone Member (Great Meadows Formation) 

1. Early Ordovician 

2. New York (NE), Vermont 

3. Fisher, D. W., 1977, Correlation of the Hadrynian, Cambrian 

and Ordovician rocks in New York State: New York State Mus. 

Map and Chart Ser., no. 25, p. 65 

4. Dolomitic, quartzo-feldspathic siltstone 

6. Range <1-34 m 7. Laminated, cross-stratified 

9. Basal unit of Great Meadows Formation; transitionally underlies Fort Edward Dolostone Member 

10. Type locality: Bushlea Farm, in pastures and abandoned 

quarry N of New York Highway 149 and 1.6 km E of Smiths 

Basin on Champlain Canal, Hartford quadrangle, Washington 

County, N.Y. Named for Winchell Creek which flows into 

canal at Dewey Bridge. 

Wink Member (Wristen Formation) 

1. Late Silurian 

2. Texas (WC) 

3. Hills, J. M., and Hoenig, M. A., 1979, Proposed type 

sections for Upper Silurian and Lower Devonian subsurface 

units in Permian Basin, west Texas: Am. Assoc. Petroleum 

Geologists Bull., v. 63, no. 9, p. 1511 

4. Limestone, dolomite, shale 

5. White, gray 

6. 41 m, range 4.5-41 m 7. Banded 

9. Disconformably overlies Fusselman Shale; conformably underlies Frame Member (Wristen Formation) 

10. Type section: Phillips Petroleum Co. 1 University Lands "H" 

well, depth-interval 5,355-5,396 m, Sec. 11, Blk. 17, University Lands Survey, War-Wink field, Winkler County, Tex. 
188 LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Winterville Formation 

1 • 

2. 

3. 

4. 

6. 

7. 

9. 

10. 

Winthrop 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

9. 

10. 

Ordovician (Caradocian and Ashgillian) 

Maine (NC) 

Roy, D. C., and Mencher, Ely, 1976, Ordovician and Silurian 

stratigraphy of northeastern Aroostook County, Maine: Geol. 

Soc. America Mem. 148, p. 34, 47 

Andesitic, basaltic, keratophyric, rhyolitic, and tuffaceous 

volcanic rocks with interlayered slate, graywacke, and chert 

>1,500 m 

Complex assemblage of submarine volcanic and sedimentary 

rocks 

Oldest rocks exposed in cores of anticlines; interfingers 

with Madawaska Lake Formation; disconformably(?) underlies 

Pyle Mountain Argillite or unconformably underlies Upper 

Silurian rocks 

Type area: Along Maine Route 11, S of Winterville, Aroostook County, Maine. 

Till Member (Wolf Creek Formation) 

Pleistocene (pre-Illinoian) 

Iowa (EC) 

Hallberg, G. R., 1980, Pleistocene stratigraphy in eastcentral Iowa: Iowa Geol. Survey Tech. Inf. Ser., no. 10, 

p. 54-64 

Silty till 

Yellowish-brown to dark-gray 

Range <1.6-4.6 m 

Loam- to light clay-loam-textured till 

Unconformably overlies informal Westburg paleosol and Alburnett Formation; underlies sediments which separate Winthrop 

from Aurora Till Member 

Type locality: Railroad cut and Winthrop core section, 2 km 

W of town of Winthrop in NW1/4 sec. 3, T. 88 N., R. 8 W., 

Buchanan County, Iowa. 

Vitoh Me.ber (Keating Formation) 

1. Early Mississippian 

2. New Mexico (SW), Arizona 

3. Armstrong, A. K., and Mamet, B. L., 1978, The Bugle and 

Witch Members of the Keating Formation, Escabrosa Group, and 

the Mississippian nomenclature in the Big Hatchet Mountains, 

Hidalgo County, New Mexico: U.S. Geol. Survey Bull. 1457-A, 

p. A92-A93 

4. Limestone composed of spiculitic-pelletoid-bryozoan-echinoderm-lime mudstone to packstone and wackestone; chert 

6. 82 m 

7. Cross-laminated, fossiliferous chert, nodular to lenticular 

9. Overlies Bugle Member (Keating Formation); unconformably 

underlies Hachita Formation (Escabrosa Group) 

10. Type section: E1/2 sec. 30, T. 29 s., R. 15 W., NE side of 

Big Hatchet Mountains, Hidalgo County, N. Mex. Named for 

Witch Well, Big Hatchet quadrangle. 

~olf Creek Formation 

1. Pleistocene (pre-Illinoian) 

2. Iowa (C) 

3. Hallberg, G. R., .1980, Pleistocene stratigraphy in eastcentral Iowa: Iowa Geol. Survey Tech. Inf. Ser., no. 10, 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

p. 12-70 

4. Till; fluvial silt, sand, and gravel; swale-fill deposits, 

peat, paleosols 

7. Till units are loam-textured, and are high in expandable 

clays, kaolinite, and illite 

8. Winthrop, Aurora, and Hickory Hills Till Members, and 

unnamed sediments between till members; informal Dysart 

paleosol between Aurora and Hickory Hills Till Members 

9. Unconformably overlies Alburnett Formation and informal 

Westburg paleosol; underlies alluvium, swale-fill, fluvial, 

and pedisediment deposits of Yarmouth through late Sangamon 

age 

189 

10. Type area: Around Wolf Creek in Geneseo, Clark, Buckingham, 

and Grant Townships, Tama County, Iowa. Many outcrops and core holes in this area are designated reference sections 

for members. 

Volr Mountain Creek Formation (Emperor Volcanic Complex) 

1. Precambrian X [Early Proterozoic] 

2. Michigan (NW) 

3. Trent, V. A., 1976, The Emperor Volcanic Complex of the East 

Gogebic Range, Michigan: U.S. Geol. Survey Bull. 1422-A, 

p. A69 

4. Pyroclastic and tectonic flow-breccia, veined amygdaloidal 

lavas 

5. Greenish-gray 

6. Range 90-150 m 7. Pillow structures, jointing 

9. Overlies intertongued unnamed basalt flows of Emperor 

Volcanic Complex and lower members of Ironwood Ironformation; underlies Copps Formation 

10. Type locality: Outcrops that flank Wolf Mountain Creek, 

tributary to Little Presque Isle River, sees. 14, 23, 24, 

and 25, T. 47 N., R. 44 W., Waketield NE quadrangle, Gogebic 

County, Mich. 

Wrights Point Member (Harney Formation) 

1. Pliocene 

2. Oregon (SE) 

3. Walker, G. W., 1979, Revisions to the 

of Harney Basin, southeastern Oregon: 

Bull. 1475, p. 30 

Olivine basalt 

3-9 m Two thin flows capping Wrights Point 

Cenozoic stratigraphy 

U.S. Geol. Survey 

4. 

6. 

7. 

9. Uppermost member of Harney Formation; overlies conglomerate 

tuffaceous sandstone and siltstone and ash beds of Harney 

Formation; top is Holocene erosion surface 

10. Type locality: Roadcuts on Oregon State Highway 205 at 

Wrights Point, sec. 33, T. 24 S., R. 31 E., Harney County, 

Oreg. 

Wristen Formation 

1. Late Silurian 

2. Texas (WC) 

3. Hills, J. M., and Hoenig, M. A., 1979, Proposed type 

sections for Upper Silurian and Lower Devonian subsurface 

units in Permian Basin, west Texas: Am. Assoc. Petroleum 
190 

4. 

5. 

6. 

8. 

9. 

10. 

LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 

Geologists Bull., v. 63, no. 9, p. 1510-1513 

Shaly limestone, calcareous shale, dolomite 

Gray, green-gray, blue-gray, white 

69 m, range 4.5-210 m 

Wink and Frame Members 

Disconformably overlies Fusselman Formation; unconformably 

underlies Thirtyone Formation 

Type section: Gulf Oil Corp. 5-SI Wristen Brothers well, 

depth-interval 2,051-2,120 m, Sec. 18, Blk. 5, H & TC 

Survey, Wickett field, Ward County, Tex. 

Wrong Mountain Quartz Monzonite (Santa Catalina Group) 

1. Middle Proterozoic 

2. Arizona (SC) 

3. Drewes, Harald, 1977, Geologic map and sections of the 

Rincon Valley quadrangle, Pima County, Arizona: U.S. Geol. 

Survey Misc. Inv. Ser. Map I-997 

4. Quartz monzonite, biotite-muscovite gneiss 

5. Light-brownish-gray 

7. Large intrusive and metasomatic(?) complex. Texture ranges 

from massive near center of Rincon gneiss dome to mediumgrained with lit-par-lit sheets on flanks of dome 

9. Intrudes Continental Granodiorite (Santa Catalina Group) and 

Pinal Schist 

10. Type area: Sec. 9, T. 16 S., R. 18 E., most accessible 

along powerline service road on Wrong Mountain on S ridge of 

Rincon Mountains, Rincon Valley quadrangle, Pima County, 

Ariz. 

Yellow Dirt Gneiss 

1. Precambrian, late(?), and (or) Paleozoic, early(?) 

2. Georgia (NW) 

3. Higgins, M. W., and McConnell, K. I., 1978, The Sandy 

Springs Group and related rocks in the Georgia Piedmont--

Nomenclature and stratigraphy: U.S. Geol. Survey 

Bull. 1457-A, p. A104-A105 (Also published in: Georgia 

Geol. Survey Bull. 93, p. 54, 1978) 

4. Biotite-epidote-muscovite-quartz-plagioclase-microcline 

gneiss 

5. Light-gray to pink 

6. Range 75-240 m 

7. Fine- to medium-grained, cataclastic textures 

9. In fault contact for long distances along SE boundary of 

Sandy Springs Group; everywhere fault-bounded 

10. Type locality: Exposures near community of Yellow Dirt, 

Lowell quadrangle, Heard County, Ga. 

Zuma Volcanics 

1. Miocene, early and middle 

2. California (SC) 

3. Yerkes, R. F., and Campbell, R .. H., 1979, Stratigraphic 

nomenclature of the central Santa Monica Mountains, Los 

Angeles County, California: U.S. Geol. Survey Bull. 1457-E, 

p. E27-E28 

4. Basaltic and andesitic flows, breccias, tuffs; minor 

volcanic sediment and interbeds of mudstone and siltstone 

6. Range 800-1,000 m 7. Exposed in elongate fault slices 
LEXICON OF GEOLOGIC NAMES OF THE UNITED STATES 191 

9. Base nowhere exposed; inferred to unconformably overlie 

Catalina Schist; intertongues with Trancas Formation; intertongues with and underlies Monterey Shale 

10. Type locality: Exposures on W side of Zuma Canyon, about 4 

km N of Point Dume, Santa Monica Mountains, SC Point Dume 

quadrangle, Los Angeles County, Calif. 

~U.S. GOVERNMENT PRINTING OFFICE: 1986-491-405:20116