OP-237. N. D. Naeser. Fission tracks in basin analysis [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 644.

OP-238. D. L. Naftz, Rebekah Brooks, J. A. Erdman, J. G. Crock, R. C. Severson and L. K. Tuck. WYOMING. Source areas and processes controlling selenium in surface water within the Kendrick Reclamation Project area, Wyoming [abstr.], in Proceedings; Wyoming Section, American Water Resources Association, second annual meeting. Am. Water Resour. Assoc. 1989. P. 7.

OP-239. D. L. Naftz, H. E. Taylor, J. A. Rice* and J. R. Ranville. WYOMING. Glacial-ice geochemistry, Knife Point Glacier, Wind River Range, Wyoming; reconnaissance-phase results [abstr.], in Proceedings; Wyoming Section, American Water Resources Association, second annual meeting. Am. Water Resour. Assoc. 1989. p. 17.

OP-240. C. R. Neal*, L. A. Taylor*, J. B. Paces and A. N. Halliday*. Identification and origin of source heterogeneities for Apollo 17 basalts using isotopic tracers [abstr.] LPI Technical Report, in Workshop on Mare volcanism and basalt petrogenesis; "astounding fundamental concepts (AFC)" developed over the last fifteen years. (L. A. Taylor, convener and others). 91-03, 1991. p. 36-38.

OP-241. P. Nelson, J. L. Mikesell, D. Johnston* and J. S. Schweitzer*. Geophysical logs in a copper-oxide orebody [abstr.] The Log Analyst, in Minerals and Geotechnical Logging Society, a chapter-at-large of SPWLA; abstracts for the Fourth international symposium. v. 32, no. 4, August 1991. p. 388-389.

OP-242. F. H. Nichols. CALIFORNIA. Exotic species change the structure and functioning of the biota of San Francisco Bay [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 83.

OP-243. W. J. Nokleberg, H. L. Foster, M. A. Lanphere, J. N. Aleinkoff and T. L. Pavlis*. ALASKA. Structure and tectonics of the Yukon-Tanana, Wickersham, Seventymile, and Stikinia terranes along the Trans-Alaskan Crustal Transect (TACT), eastcentral Alaska [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 84.

OP-244. J. D. Obradovich and G. A. Izett. WYOMING. 40 39

"Ar/Ar ages of upper Cenozoic Yellowstone Group tuffs (abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 84.

OP-245. P. G. Okubo, J. S. Nakata and R. Y. Koyanagi. HAWALL. Seismic monitoring at the Hawaiian Volcano Observatory [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 84-85.

OP-246. J. S. Oldow*, H. G. Avé Lallemant*, R. R. Gottschalk* and L. W. Snee. ALASKA. Timing and kinematics of Cretaceous contraction and extension in the southern Brooks Range, Alaska (abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 85.

OP-247. J. S. Oldow*, H. G. Avé Lallemant*, R. R. Gottschalk* and L. W. Snee. ALASKA. Timing and kinematics of Cretaceous contraction and extension in the southern Brooks Range, Alaska [abstr.] Eos, Transactions, American Geophysical Union, in AGU 1991 fall meeting. v. 72, no. 44, October 29, 1991. p. 295.

OP-248. J. A. Olson. CALIFORNIA. Seismotectonics of the southem San Francisco Bay area, Califomia [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 85.

OP-249. J. A. Olson, C. M. Wentworth and P. K. Showalter. CALIFORNIA. Seismicity of the southem San Francisco Bay region, California, and its correlation with mapped faults [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 85.

OP-250. S. K. Omarzai*, R. S. Coe* and J. A. Barron. CALIFORNIA. Magnetostratigraphy; an excellent tool for muchneeded numerical age-dating in the Monterey Formation of Califomia [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 648.

OP-251. D. H. Oppenheimer and N. G. MacGregor-Scott. CALIFORNIA. Seismic potential of the East San Francisco Bay region of California [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 85. OP-252. J. R. Oray, T. J. Lopes and Laurie Wirt. ARIZONA. Water quality in uranium-mine pits and ground water in the Cameron uranium mining belt, Arizona [abstr.], in Minimizing risk to the hydrologic environment; 1990 spring meeting. Am. Inst. Hydrol. 1990. p. 19-20.

OP-253. S. J. Owen-Joyce. Accounting for water use along the Colorado River, Hoover Dam to Mexico [abstr.], in Minimizing risk to the hydrologic environment; 1990 spring meeting. Am. Inst. Hydrol. 1990. p. 22.

OP-254. R. A. Page, C. D. Stephens and G. S. Fuis. ALASKA. Seismicity and current tectonics of south-central Alaska [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 86.

OP-255. F. L. Paillet. Applications of graphical overlays in geotechnical log analysis [abstr.] The Log Analyst, in Minerals and Geotechnical Logging Society, a chapter-at-large of SPWLA; abstracts for the Fourth international symposium. v. 32, no. 4, August 1991. p. 389.

OP-256. B. E. Patrick*, W. S. Dinklage* and A. B. Till.

ALASKA. Metamorphism and progressive deformation in the Walker Lake region of the southern Brooks Range, Alaska [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 87.

OP-257. W. W. Patton, Jr. ALASKA. Deep crustal composition of the Yukon-Koyukuk Basin, Alaska [abstr. | Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 88.

OP-258. C. A. Perry. Mid-continent herbicide initiative, U.S. Geological Survey [abstr.] Water and the Future of Kansas Conference, Proceedings, in 7th annual water and the future of Kansas conference; Controlling water contamination. (R. A. Black, chairperson and others). 7, 1990. p. 15.

OP-259. D. H. Peterson and D. R. Cayan*. CALIFORNIA. Climatic variability in the San Francisco Bay estuarine system [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 88.

OP-260. J. A. Peterson. Regional stratigraphy and petroleum geology; North Africa-Middle East [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 652-653. OP-261. J. A. Peterson. UTAH. Aneth oil field, giant carbonate stratigraphic trap, Paradox Basin, Utah, U.S.A. [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. P. 653.

OP-262. R. L. Phillips. CALIFORNIA. Depositional environ

ments of the Santa Margarita Formation in the Miocene Santa Maria Basin, Huasna Syncline [abstr.] AAPG Bulletin, in AAPGSEPM-SEG-SPWLA Pacific Section annual meeting. v. 75, no. 2, February 1991. p. 377.

OP-263. George Plafker, K. R. Lajoie and Meyer Rubin. ALASKA. Determining recurrence intervals of great subduction zone earthquakes in southern Alaska by radiocarbon dating [abstr.] Radiocarbon, in Program and abstracts of the 14th international radiocarbon conference. v. 33, no. 2, 1991. P. 231-232. OP-264. L. N. Plummer and E. C. Prestemon. Geochemical modeling and radiocarbon dating of groundwater; recent software developments and field examples [abstr.] Radiocarbon, in Program and abstracts of the 14th intemational radiocarbon conference. v. 33, no. 2, 1991. p. 232.

OP-265. M. L. Pomes, E. M. Thurman and C. M. Tate*. KANSAS. Konza Prairie Research Natural Area; how pristine is pristine? [abstr.] Water and the Future of Kansas Conference, Proceedings, in 7th annual water and the future of Kansas conference; Controlling water contamination. (R. A. Black, chairperson and others). 7, 1990. p. 16.

OP-266. D. J. Ponti, K. R. Lajoie and C. L. Powell. CALIFORNIA. Upper Pleistocene marine terraces in San Pedro, southwestern Los Angeles Basin, California; implications for aminostratigraphy and coastal uplift [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 89.

OP-267. S. D. Porter. KENTUCKY. Distribution of major ions and trace elements in streambed sediments of the Kentucky River basin [abstr.], in Proceedings; Kentucky water resources symposium. Lexington, KY: Univ. Ky. 1991. p. 23-24.

OP-268. C. J. Potter, R. E. Zartman and Kopal Jha*. WASHINGTON. New U-Pb zircon ages provide improved constraints on structural evolution of the Okanogan core complex, Wash. [abstr.] Abstracts with Programs - Geological Society of America,

in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 90.

OP-269. R. E. Powell. CALIFORNIA. Do structures exist that could have accommodated Paleogene docking of exotic Salinian and Peninsular Ranges terranes? [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 90.

OP-270. A. A. Pucci, Jr., T. A. Ehlke and J. P. Owens. NEW JERSEY. Characteristics of confining units and their potential effects on water quality in the upper and middle aquifers of the Potomac-Raritan-Magothy aquifer system, New Jersey coastal plain [abstr.] Eos, Transactions, American Geophysical Union, in AGU-MSA 1991 spring meeting. v. 72, no. 17, April 23, 1991. P. 115.

OP-271. C. B. Purdy*, George Burr, G. R. Helz* and A. C. Mignerey*. MARYLAND. Dating groundwater in coastal plain aquifers in southern Maryland using DOC and DIC 14c ages; an

evaluation by comparison with other dating methods [abstr.] Radiocarbon, in Program and abstracts of the 14th intemational radiocarbon conference. v. 33, no. 2, 1991. p. 234.

OP-272. D. B. Radtke. ARIZONA, CALIFORNIA, NEVADA. Contaminant risks in the lower Colorado River valley, Arizona, Califomia, and Nevada [abstr.], in Minimizing risk to the hydrologic environment; 1990 spring meeting. Am. Inst. Hydrol. 1990. p. 23.

OP-273. J. G. Rankl. An approach for computing sediment loads transported by ephemeral flows [abstr.], in Proceedings; Wyoming Section, American Water Resources Association, second annual meeting. Am. Water Resour. Assoc. 1989. p. 21.

OP-274. D. H. Rapp. U.S. Geological Survey's new water-levelsensing instrumentation [abstr.], in Minimizing risk to the hydrologic environment; 1990 spring meeting. Am. Inst. Hydrol. 1990. p. 23.

OP-275. O. B. Raup and R. J. Hite. UTAH, COLORADO. Evaporite cycles and cycle boundaries in the upper part of the Paradox Member, Hermosa Formation of Pennsylvanian age in the Paradox Basin, Utah and Colorado [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 658. OP-276. R. L. Reynolds, M. B. Goldhaber and M. L. Tuttle. Sulfidization and magnetization above hydrocarbon reservoirs [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. P. 661.

OP-277. D. D. Rice and R. M. Flores. WYOMING, MONTANA. Controls on bacterial gas accumulations in thick Tertiary coal beds and adjacent channel sandstones, Powder River basin, Wyoming and Montana [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 661.

OP-278. F. N. Robertson. ARIZONA. Radiocarbon dating in the San Pedro Valley, southeastern Arizona [abstr.] Radiocarbon, in Program and abstracts of the 14th international radiocarbon conference. v. 33, no. 2, 1991. p. 236-237.

OP-279. D. L. Rudolph*, M. A. Celia*, R. G. Kachanoski* and D. R. LeBlanc. MASSACHUSETTS. Field-scale infiltration and tracer experiments in unsaturated sand and gravel, Cape Cod, Massachusetts [abstr.] Eos, Transactions, American Geophysical Union, in AGU-MSA 1991 spring meeting. v. 72, no. 17, April 23, 1991. p. 114.

OP-280. C. S. Savard. NEVADA. Correlation integrals of South Twin River and Steptoe Creek, Nevada, streamflow [abstr.] Eos, Transactions, American Geophysical Union, in AGU-MSA 1991 spring meeting. v. 72, no. 17, April 23, 1991. p. 60.

OP-281. J. W. Schmoker and D. K. Higley. COLORADO. Predictive porosity models for the Lower Cretaceous J Sandstone, Denver Basin, Colorado [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. P. 667-668.

OP-282. C. H. Scholz✶ and C. C. Barton. The fractal nature of hydrocarbon deposits; 1, Size distributions [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 668.

OP-283. M. E. Smith. WYOMING. Channel characteristics of the Bear River at Evanston, Wyoming [abstr.], in Proceedings; Wyoming Section, American Water Resources Association, second annual meeting. Am. Water Resour. Assoc. 1989. p. 22. OP-284. C. W. Spencer, J. C. Lorenz* and C. A. Brown*. Application of horizontal drilling to tight gas reservoirs [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 675.

OP-285. J. K. Stamer, L. M. Pope and R. B. Zelt. KANSAS, NEBRASKA. Occurrence and distribution of pesticides in the lower Kansas River basin in Kansas and Nebraska [abstr.] Water and the Future of Kansas Conference, Proceedings, in 7th annual water and the future of Kansas conference; Controlling water contamination. (R. A. Black, chairperson and others). 7, 1990. p. 25-26.

OP-286. R. G. Stanley, S. Y. Johnson, M. L. Tuttle, M. A. Mason*, C. C. Swisher, III*, M. L. Thornton*, D. R. Vork*, M. V. Filewicz*, R. B. Cole* and J. D. Obradovich. CALIFORNIA. Age, correlation, and origin of the type Lospe Formation (lower Miocene), Santa Maria Basin, Central Califomia [abstr.] AAPG Bulletin, in AAPG-SEPM-SEG-SPWLA Pacific Section annual meeting. v. 75, no. 2, February 1991. p. 382. OP-287. M. B. Steiner*, Michael Morales* and E. M. Shoemaker. Relative ages of fossil caches, synchroneity of major lithology change, and formational age, as determined by magnetostratigraphic correlation [abstr.] AAPG Bulletin, in AAPG 1991 annual convention_with_DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 676. OP-288. D. D. Susong, M. L. Smalley and M. E. Cooley. WYOMING. Ground-water resources of Washakie County, Wyoming [abstr.], in Proceedings; Wyoming Section, American Water Resources Association, second annual meeting. Am. Water Resour. Assoc. 1989. p. 12.

OP-289. B. J. Szabo, C. V. Haynes, Jr.* and T. A. Maxwell*. Comparisons of uranium series and radiocarbon dates on lacustrine

deposits of the eastern Sahara [abstr.] Radiocarbon, in Program and abstracts of the 14th international radiocarbon conference. v. 33, no. 2, 1991. p. 249.

OP-290. K. I. Takahashi and D. K. Higley. The history of exploration in petroleum provinces in the United States [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 678-679.

OP-291. M. E. Taylor. H. E. Cook and Ludmila Melnikova*. Biofacies evidence for Late Cambrian low-paleolatitude oceans, Westem United States and Central Asia [abstr.] AAPG Bulletin, in AAPG-SEPM-SEG-SPWLA Pacific Section annual meeting. v. 75, no. 2, February 1991. p. 383.

OP-292. A. B. Till and T. E. Moore. ALASKA. Tectonic relations of the schist belt, southern Brooks Range, Alaska [abstr. | Eos, Transactions, American Geophysical Union, in AGU 1991 fall meeting. v. 72, no. 44, October 29, 1991. p. 295-296. OP-293. V. R. Todd, S. E. Shaw*, G. H. Girty* and R. C. Jacbens. CALIFORNIA. A probable Jurassic plutonic arc of continental affinity in the Peninsular Ranges Batholith. Souther Califomia; tectonic implications [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 104.

OP-294. A. J. Tomlinson* and B. L. Murchey. NEVADA. Lithotectonic units in the Golconda Allochthon, Nevada [abstr.] AAPG Bulletin, in AAPG-SEPM-SEG-SPWLA Pacific Section annual meeting. v. 75, no. 2, February 1991. p. 383-384. OP-295. G. F. Ulmishek. Pripyat Basin, U.S.S.R.; an oil productive middle Paleozoic rift [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 685. OP-296. G. F. Ulmishek. Volga-Ural Basin, U.S.S.R.: rich petroleum systems with a single source rock [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 685. OP-297. M. B. Underwood*, K. Shelton*, M. M. Laughland*, R. Solomon*, R. J. McLaughlin, P. C. Russell and D. H. Sorg. CALIFORNIA. Miocene thermal-maturity anomalies at Loma Prieta, Mt. San Bruno, and Bolinas, Central Califomia coast [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 105.

OP-298. P. C. Van Metre. ARIZONA, NEW MEXICO. The impact of uranium mine dewatering on dissoved gross-alpha and gross-beta activities in the Puerco River, Arizona and New Mexico [abstr.], in Minimizing risk to the hydrologic environment; 1990 spring meeting. Am. Inst. Hydrol. 1990. p. 25. OP-299. D. J. Varnes. VIRGIN ISLANDS. The cyclic and fractal seismic series preceding the February 14, 1980, M 4.8 earthquake near the Virgin Islands [abstr.] Eos, Transactions, American Geophysical Union, in AGU-MSA 1991 spring meeting. v. 72, no. 17, April 23, 1991. p. 58.

OP-300. Paul VonGuerard, R. A. Harnish and D. M. McKnight. Streamflow in the lower Taylor Valley, Antarctica, 1990-91 [abstr.] Eos, Transactions, American Geophysical Union, in AGUMSA 1991 spring meeting. v. 72, no. 17, April 23, 1991. p.

109.

OP-302. P. E. Wannamaker*, J. R. Booker*, J. H. Filloux*, A. G. Jones*, G. R. Jiracek*, A. D. Chave*, H. S. Waff*, J. A. Stodt*. C. T. Young*, Mario Martinez*, L. K. Law*, T. Yukitake*, J. S. Segawa*, Anthony White* and A. W. Green. Magnetotelluric transect of the Juan de Fuca subduction system in EMSLAB [abstr.] Abstracts - Workshop on Electromagnetic Induction in the Earth and Moon, in Ninth workshop on Electromagnetic induction in the Earth and Moon. (M. S. Zhdanov, editor and others). 9, 1988. p. 129.

OP-303. J. E. Wame*, M. H. Gardner*, F. G. Ethridge*, W. S. Houston* and R. M. Flores. ALASKA. Tertiary non-marine stratigraphic section along Shelikof Straits, Katmai National Park, Alaska [abstr.] Abstracts with Programs Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 107. OP-304. C. M. Wentworth and M. C. Blake, Jr. CALIFORNIA. Preliminary geologic map of the San Jose 1:100,000 Quadrangle, Califomia [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 108. OP-305. R. A. Wharton*, C. P. McKay*, G. D. Clow and D. T. Andersen*. Changes in ice-cover thickness and lake level of Lake Hoare, Antarctica; implications for climatic change [abstr.] Eos, Transactions, American Geophysical Union, in AGU-MSA 1991 spring meeting. v. 72, no. 17, April 23, 1991. p. 109. OP-306. K. J. Whidden*, S. P. Lund*, D. J. Bottjer*, D. E. Champion and D. G. Howell. CALIFORNIA. Paleomagnetic evidence from Upper Cretaceous strata for autochthoneity of the central block of Salinia [abstr.] Abstracts with Programs - Geolo

gical Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991.

P. 109.

OP-307. R. J. Wilber*, R. B. Halley and J. D. Milliman*. Slope depositional processes along western Great Bahama Bank; a rapidly prograding carbonate platform [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 693. OP-308. C. J. Wilson* and Wes Hildreth. CALIFORNIA. Bishop Tuff revisited; new insights on eruption timing [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 109.

OP-309. K. M. Wojcik*, C. E. Barker, R. H. Goldstein* and A. W. Walton*. KANSAS. Elevated thermal maturation in Pennsylvanian rocks, Cherokee Basin, southeastem Kansas; importance of regional fluid flow [abstr.] AAPG Bulletin, in AAPG 1991 annual convention with DPA/EMD divisions and SEPM, an associated society. v. 75, no. 3, March 1991. p. 696.

OP-310. E. W. Wolfe, T. P. Miller and T. L. Wright. The status of volcano monitoring and hazards assessment in the Westem United States [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 110. OP-311. F. L. Wong and R. A. Koski. Inorganic and biogenic microstructures of silica, sulfide, and oxide minerals in hydrothermal chimney deposits, southern Juan de Fuca Ridge [abstr.] Abstracts with Programs - Geological Society of America, in Geological Society of America, Cordilleran Section, 87th annual meeting. v. 23, no. 2, March 1991. p. 110.

OP-312. M. L. Zoback. Global pattems of intraplate stress and constraints on seismicity [abstr.] Revista Brasileira de Geofisica, in 1o congresso da Sociedade Brasileira de Geofisica (1st congress of the Brazilian Society of Geophysics). v. 7, no. 1, 1988. p. 48.

Standard topographic maps are usually published in 7.5- and 15-minute quadrangles. The map location is given by the latitude and longitude of the southeast (lower right) corner of the quadrangle. Location, scale, and contour interval are indicated for each map in the computer-generated list below. The date of the map is shown in the column following the map name; a second date indicates the latest revision. Provisional maps are essentially standard topographic maps published with modified map finishing and field and compilation procedures. Photorevised maps have not been field checked. Series converted maps include 15-minute maps compiled from 7.5-minute maps, and 7.5-minute maps compiled from 7.5-minute source materials initially published as 15-minute maps. Orthophotomaps are multicolor photographic-image maps in standard quadrangle format with added topographic detail. Orthophotoquads are monocolor or multicolor photographic-image maps in standard quadrangle format without topographic detail. Most monocolor orthophotoquads are not being published but are available in the form of diazo or photographic prints. The Index to Orthophotoquad Mapping showing information about available published and unpublished orthophotoquads is free on request from the distribution centers listed at the back of the Monthly

List. County maps are multicolor topographic maps at scales of 1:50,000 or 1:100,000. Some counties require more than one map and the cost is $4 per map. Level of content may vary between States, and State sales indexes should be consulted for a more detailed description of each map. Planimetric maps at intermediate scales of 1:50,000 or 1:100,000 are available in both quadrangle and county format for selected areas of the country. Most of these maps are not being published but are available in other forms. Copies of the drawings which comprise these maps are available either as a composite of all features or separately by feature. An Index to Intermediate-Scale Series Mapping showing information about available published and unpublished intermediate-scale maps is free on request from the distribution centers listed at the back of the Monthly List.

Standard quadrangle maps and orthophotoquads are sold for $2.50 per copy. Discount rates and ordering instructions are given at the back of the Monthly List. State topographic indexes and catalogs are free on request. Each State index shows the areas mapped and the catalog contains ordering information and forms, along with a list of local dealers who sell topographic maps.

RMKS

RMKS

# DENOTES A 7.5 X 15-MINUTE FORMATTED MAP.

* INDICATES CONTOUR INTERVALS IN METERS.