OP-108. D. P. Hill. CALIFORNIA. Alert level criteria for unrest in the Long Valley-Mono Craters region, eastern California [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (L G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 27.

OP-109. D. G. Howell. CALIFORNIA. Salinia is surely suspect [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. 37.

OP-110. Stephen Hughes and J. H. Luetgert. NEW YORK. Crustal structure of the southeastern Grenville Province in Ontario and New York State [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 31.

OP-111. L. K. Hutton* and L. M. Jones. CALIFORNIA. Changes in the rate of seismicity in Southem California between 1932 and 1989 [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 47.

OP-112. R. C. Jachens, V. R. Todd, D. M. Morton and Andrew Griscom. CALIFORNIA. Constraints on the structural evolution of the Peninsular Ranges Batholith, Califomia, from a new aeromagnetic map [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. 38. OP-113. R. C. Jachens, V. R. Todd, D. M. Morton and Andrew Griscom. CALIFORNIA. Constraints on the structural evolution of the Peninsular Ranges Batholith, California, from a new aeromagnetic map [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 44.

OP-114. S. M. Jackson*, J. E. Zollweg✶ and C. J. Langer. IDAHO. 1984 Devil Canyon sequence near Challis, Idaho; structural complexity near the north end of the Borah Peak aftershock zone [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. P. 51.

OP-115. D. A. John and E. H. McKee. NEVADA. Late Cenozoic volcanotectonic evolution of the southem Stillwater Range, west-central Nevada [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. 39. OP-116. D. L. Jones* and E. E. Brabb. CALIFORNIA. New geologic map of Contra Costa and Alameda counties, 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. 40.

OP-119. W. B. Joyner, K. W. Campbell and S. C. Harmsen. Near-source simulation of earthquake ground motion based on the stochastic omega-square model [abstr.] Seismological Research Letters, in 83nd annual meeting of the Seismological Society of America. v. 59, no. 1, March 1988. p. 10.

OP-120. H. A. Karl, D. E. Drake, W. C. Schwab and J. L. Chin. CALIFORNIA. Use of sidescan sonar for detecting barrels of low-level radioactive waste, Farallone Escarpment, 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. 40.

OP-121. D. K. Keefer, E. L. Harp, G. B. Griggs* and T. E. Spittler*. CALIFORNIA. Large landslides near the San Andreas Fault triggered by the October 17, 1989, Loma Prieta, California, earthquake [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. 41.

OP-122. R. W. Kistler and D. E. Champion. CALIFORNIA. A strontium and oxygen isotopic study of granitic rocks from Bodega Head to the Santa Lucia Range in the northern Salinian Block, 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. 42. OP-123. A. N. Kover and J. E. Jones. The U.S. Geological Survey's side-looking airbome radar program; CD-ROMs for improved data accessibility [abstr.] Technical Papers of the American Congress of Surveying and Mapping, in Countdown to the 21st century; 1990 ACSM-ASPRS annual convention: ACSM 50th annual meeting; ASPRS 56th annual meeting. 50, Vol. 4, 1990. p. 493. OP-124. A. N. Kover and J. E. Jones. Side-looking airbome radar image data for the geosciences; the first quarter century [abstr.] Technical Papers of the American Congress of Surveying and Mapping, in Countdown to the 21st century; 1990 ACSMASPRS annual convention; ACSM 50th annual meeting: ASPRS 56th annual meeting. 50, Vol. 4, 1990. p. 250-252. OP-125. K. M. Kuivila and J. L. Domagalski. CALIFORNIA. Organic contaminants in San Francisco Bay-Estuary [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. 43.

OP-126. K. A. Kvenvolden and R. E. Kayen. Gas hydrates as a geologic hazard in submarine environments [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. 43.

OP-127. V. F. Labson, J. W. Cady, C. L. Long, J. A. Sampson and F. R. Weber. ALASKA. Deep crustal geoelectric structure in the vicinity of the Tintina fault zone, north-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. 43.

OP-128. V. F. Labson, B. D. Rodriguez, J. A. Sampson and R. J. Bisdorf. CALIFORNIA. Electrical resistivity mapping in the southem San Francisco Bay region [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. 43.

OP-129. M. T. Ledbetter*, H. G. Greene, J. M. Gardner-Taggart*, Robert Barminski* and T. E. Chase*. CALIFORNIA. Damage due to sediment liquefaction both offshore and onshore at Moss Landing, CA as a result of the Loma Prieta earthquake [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. 44.

OP-130. W. H. Lee and Robert Banfill. Using personal computers for seismic network operations and research [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 22. OP-131. M. D. Lewan. Understanding generation and expulsion of hydrocarbons in sedimentary basins through experiments [abstr.] AAPG Bulletin, in Distinguished lecture tours, 1991-1992; abstracts. v. 75, no. 11, November 1991. p. 1807. OP-132. J. J. Lienkaemper and Glenn Borchardt*. CALIFORNIA. Holocene slip rate of the Hayward Fault at Union City, California [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (L. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 14.

OP-133. A. G. Lindh. CALIFORNIA. A seismotectonic model for the San Andreas fault system [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 14. OP-134. Michael Lisowski, J. C. Savage and W. H. Prescott. CALIFORNIA. The velocity field along the San Andreas Fault in Northern Califonia [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 11.

OP-135. P. C. Lyons, P. A. Hacquebard* and W. F. Outerbridge. Evidence of Carboniferous volcanic ash in Pictou Group (Westphalian D) Sydney Coalfield, Nova Scotia, Canada [abstr.] AAPG Bulletin, in AAPG Eastern Section meeting; abstracts. v. 75, no. 8, August 1991. p. 1387.

OP-136. G. A. Marshall, R. S. Stein and Wayne Thatcher. CALIFORNIA. From short to long period observations; are geodetic models of the Loma Prieta earthquake consistent with the results of seismological studies? [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 35.

OP-137. D. G. Masson*, Q. J. Huggett*, R. B. Kidd* and J. V. Gardner. Sediment transport by the Saharan sediment slide; a new view with 30 KHZ deep-tow sidescan sonar [abstr.] Intemational Sedimentological Congress, in 13th international sedimentological congress; abstracts, posters. 13, 1990. p. 103-104.

OP-138. D. G. Masson*, Q. J. Huggett*, P. P. Weaver*, R. B. Kidd* and J. V. Gardner. Quatemary sedimentary processes on the northwestern African continental margin; an integrated study using side-scan sonar, high-resolution profiling, and core data [abstr.] AAPG Bulletin, in AAPG intemational conference; abstracts. v. 75, no. 8, August 1991. p. 1416.

OP-139. C. D. Masters. Global resources and prediction [abstr.] AAPG Bulletin, in AAPG international conference; abstracts. v. 75, no. 8, August 1991. p. 1416.

OP-140. A. F. McGarr, Mehmet Celebi, E. D. Senibera, T. Noce and C. S. Mueller. CALIFORNIA. Ground motion at the San Francisco Airport from the Loma Prieta earthquake sequence, 1989 [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section: 86th annual meeting. (L. G. Wong, chairperson and others). v. 62, no. 1. March 1991. p. 29.

OP-141. Carlos Mendoza and S. H. Hartzell. Aftershock pattems and mainshock faulting [abstr.] Seismological Research Letters, in 83nd annual meeting of the Seismological Society of America. v. 59, no. 1, March 1988. p. 6.

OP-142. B. M. Miller. An object-oriented expert system for sedimentary basin analysis [abstr.] AAPG Bulletin, in AAPG Eastern Section meeting; abstracts. v. 75, no. 8, August 1991. p. 1388. OP-143. J. J. Mori and C. M. Dietel. CALIFORNIA. Nearfield waveform data recorded on a small seismic array for aftershocks of the 1990 Upland, California earthquake [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 15-16.

OP-144. C. S. Mueller. CALIFORNIA. Estimation of ground motions of the 1983 Coalinga, California, main shock using aftershock seismograms as empirical Green's functions [abstr.] Seismological Research Letters, in 83nd annual meeting of the Seismological Society of America. v. 59, no. 1, March 1988. p.

10.

OP-145. R. D. Norris. WASHINGTON. Seismic observations of rock and debris falls at Mount St. Helens, Washington [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I.

G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 16.

OP-146. P. G. Okubo, J. S. Nakata and R. Y. Koyanagi. HAWAII. Seismic monitoring at the Hawaiian Volcano Observatory [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 28.

OP-147. J. A. Olsen. CALIFORNIA. Seismotectonics of the southern San Francisco Bay area, California [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. P. 14. OP-148. D. H. Oppenheimer and N. G. MacGregor-Scott. CALIFORNIA. Seismic potential of the East San Francisco Bay region of Califomia [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 13.

OP-149. W. F. Outerbridge, P. C. Lyons and A. F. Keiser*. The ash-fall pattern of the Fire Clay tonstein, central Appalachian Basin; paleogeographic and plate tectonic implications [abstr.] AAPG Bulletin, in AAPG Easter Section meeting; abstracts. v. 75, no. 8, August 1991. p. 1389.

OP-150. R. L. Payne. Automated data processing of toponymic data for cartographic applications [abstr.] Abstracts - Congress of the International Geographical Union, in 26th congress of the International Geographical Union; abstracts. (Graeme Aplin, compiler). 26, 1988. p. 444.

OP-151. R. L. Phillips, Arthur Grantz, M. W. Mullen, T. E. Chase and J. Young. Preliminary stratigraphy and sediment processes on southeastern Northwind Ridge, Arctic Ocean [abstr.] International Sedimentological Congress, in 13th intemational sedimentological congress; abstracts, posters. 13, 1990. p. 176. OP-152. George Plafker, K. R. Lajoie and Meyer Rubin. ALASKA. New data on the recurrence interval and seismic cycle for great 1964-type earthquakes in the Copper River delta, Alaska [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991.

p.

38.

OP-153. J. B. Roen. R. T. Ryder and Wallace de Witt, Jr. Atlas of Appalachian Basin oil and gas plays; the Oriskany Sandstone play; a preliminary example [abstr.] AAPG Bulletin, in AAPG Eastem Section meeting; abstracts. v. 75, no. 8, August 1991. p. 1390.

OP-154. J. A. Rogers and C. D. Stephens. SSAM; a PC-based

realtime seismic spectral amplitude measurement system for volcano monitoring [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 22.

OP-155. R. T. Ryder, R. C. Burruss and J. R. Hatch. OHIO. Geochemistry and origin of oil from Cambrian and Ordovician reservoirs in eastern and central Ohio [abstr.] AAPG Bulletin, in AAPG Eastem Section meeting; abstracts. v. 75, no. 8, August 1991. p. 1390.

OP-156. J. C. Savage and Michael Lisowski. WASHINGTON. Strain measurements imply potential for a great subduction earthquake off the coast of Washington [abstr.] Seismological Research Letters, in Living on the edge: Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 40.

OP-157. C. J. Schenk, D. L. Gautier, G. R. Olhoeft and J. E. Lucius. Structures in eolian dunes as viewed with ground-penetration radar [abstr.] International Sedimentological Congress, in 13th international sedimentological congress; abstracts, posters. 13, 1990. p. 197.

OP-158. S. Y. Schwartz*, L. J. Ruff*, Thome Lay* and J. W. Dewey. Fault zone heterogeneity and seismicity in the southern Kurile Islands arc [abstr.] Seismological Research Letters, in 83nd annual meeting of the Seismological Society of America. v. 59, no. 1, March 1988. p. 5.

OP-159. J. E. Shigley* and E. E. Foord. UTAH. Geology and mineralogy of the red beryl occurrence in the southem Wah Wah Mountains, Beaver County, Utah [abstr.] Program and Abstracts Friends of Mineralogy and Mineralogical Society of America Mineralogical Symposium, in Classic mineral localities, abstracts. 7, 1985. p. 12-13.

OP-160. J. D. Sims. CALIFORNIA. Distribution and rate of slip across the San Andreas transform boundary, Hollister area, Central Califomia [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 13.

OP-161. P. D. Spudis. Young dark mantle deposits on the Moon [abstr.] LPI Technical Report, in Workshop on Lunar volcanic glasses; scientific and resource potential. (J. W. Delano, editor and others). 90-02, 1990. p. 60-61.

OP-162. L. A. Stach and T. C. Wallace*. Regional moment-tensor inversion for moderate sized earthquakes in the Western United States [abstr.] Seismological Research Letters, in 83nd annual meeting of the Seismological Society of America. v. 59, no. 1, March 1988. p. 4.

OP-163. F. A. Stanke. ILLINOIS, INDIANA, WISCONSIN. Using a geographic infomation system to relate human and natural factors to stream water quality in the upper Illinois River basin in Illinois, Indiana, and Wisconsin [abstr.], in Water resources, GIS applications, and wetlands, with special references to the Illinois River; proceedings of the annual conference of the Illinois Section of the American Water Resources Association. Am. Water Resour. Assoc., Ill. Sect. 1989. unpaginated.

OP-164. L. T. Steyaert. Applications of integrated spatial and multitemporal data analysis techniques for global change research [abstr.] Technical Papers of the American Congress of Surveying and Mapping, in Countdown to the 21st century; 1990 ACSM

ASPRS annual convention; ACSM 50th annual meeting; ASPRS 56th annual meeting. 50, Vol. 4, 1990. p. 378.

OP-165. X. M. Tang*, C. H. Cheng* and F. L. Paillet. Characterization of permeable structures using borehole Stoneley waves [abstr.] The Log Analyst, in The SPWLA thirty-second annual logging symposium. v. 32, no. 4, April 1991. p. 158.

OP-166. Wayne Thatcher and D. P. Hill. Kinematic evidence for fault weakness in strike-slip and extensional environments [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 39.

OP-167. G. F. Ulmishek. Structural evolution and petroleum productivity of the Baltic Basin [abstr.] AAPG Bulletin, in AAPG international conference; abstracts. v. 75, no. 8, August 1991. p. 1423.

OP-168. F. L. Vemon*, J. N. Brune* and J. B. Fletcher. CALIFORNIA. Source parameters of small earthquakes in the Anza array estimated from 300 m borehole recordings [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 16. OP-169. D. J. Wald*, D. V. Helmberger* and T. H. Heaton. CALIFORNIA. The rupture initiation process of a large earthquake: Loma Prieta [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 29.

OP-170. L. A. Wald and T. H. Heaton. CALIFORNIA. Rayleigh wave observations of the California regional networks from the 17 October 1987 New Britain earthquake [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. P. 32.

OP-171. S. R. Walter. CALIFORNIA. Ten years of earthquakes at Lassen Peak, Mount Shasta, and Medicine Lake volcanoes. Northern Califomia: 1981-1990 [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 25.

OP-172. P. L. Ward. Seismic Unified Data System (SUDS) [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 22.

OP-173. R. E. Weems and C. R. Wiggs*. VIRGINIA, MARYLAND. Parasuchian occurrences in Upper Triassic rocks of the Culpeper Basin of Virginia and Maryland [abstr.] Virginia Journal of Science, in Abstracts of papers of the Sixty-ninth annual meeting of the Virginia Academy of Science. v. 42, no. 2, 1991. p. 222.

OP-174. C. J. Wilson* and Wes Hildreth. CALIFORNIA. Bishop Tuff revisited; new insights on eruption timing [abstr.] Seismological Research Letters, in Living on the edge: Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p.

27.

OP-175. E. W. Wolfe, T. P. Miller and T. L. Wright. The status of volcano monitoring and hazards assessment in the Westem United States [abstr.] Seismological Research Letters, in Living on the edge; Joint meeting of the Seismological Society of America and the Geological Society of America Cordilleran Section; 86th annual meeting. (I. G. Wong, chairperson and others). v. 62, no. 1, March 1991. p. 25.

OP-176. I. G. Wong* and A. F. McGarr. Non-double-couple failure in mine seismicity [abstr.] Seismological Research Letters, in 83nd annual meeting of the Seismological Society of America. v. 59, no. 1, March 1988. p. 5.

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.