Introduction
Plate 62 refers to a specific map sheet within the United States Geological Survey (USGS) 7.5‑minute quadrangle series. The sheet covers a region that includes portions of the Sierra Nevada mountain range in eastern California and western Nevada. Published in the mid‑1970s, Plate 62 was created to provide detailed topographic and geological information for a variety of users, including scientists, planners, and recreational users. The map presents contour lines at a 1:24,000 scale, illustrating elevation changes, hydrological features, geological formations, and human infrastructure such as roads and trails. It has become a reference point for studies of alpine geology, hydrology, and land use in the western United States.
In the context of USGS mapping, each plate is identified by a sequential number that corresponds to a geographic area. Plate 62 is one of the 1,400+ plates that collectively cover the continental United States. Its numbering follows a systematic arrangement that begins in the north‑west and proceeds eastward and southward. The designation “Plate 62” is therefore a technical identifier that signals the sheet’s place within the national mapping framework.
History and Development
Early Mapping Efforts
Topographic mapping in the United States began in earnest during the 19th century with the efforts of the USGS and other agencies. Early surveys were conducted using ground‑based instruments such as theodolites and chains, and the resulting maps were often drawn by hand. As technology improved, aerial photography and photogrammetry were introduced in the 1930s, providing more accurate and efficient means of capturing terrain data. By the 1950s, the USGS had established a standard set of map scales and a quadrangle system that divided the country into manageable units.
Development of the 7.5‑Minute Series
The 7.5‑minute quadrangle series, with a nominal scale of 1:24,000, was introduced to deliver detailed topographic information at a level of granularity suitable for engineering, scientific, and recreational purposes. The series was developed in the 1960s and 1970s, with a focus on consistency in representation, symbol use, and accuracy. Each plate in the series was produced through a combination of field surveys, aerial photography, and cartographic refinement. Plate 62 was among the first batch of plates completed as part of this nationwide initiative.
Production of Plate 62
Production of Plate 62 involved a multi‑step process. Field teams conducted ground control surveys to establish precise geographic coordinates for key features. Aerial photographs were taken during the winter season to maximize visibility of snow‑covered features and reduce cloud cover. Photogrammetric techniques were applied to the photographs to derive elevation data, which was then cross‑checked against ground survey points. The data were entered into a computer system that generated contour lines and other topographic elements. Cartographers refined the preliminary map using manual editing, ensuring that all symbols met USGS standards.
Publication and Distribution
The final printed version of Plate 62 was released in 1976. It was printed on high‑quality paper using lithographic techniques, and each sheet was bound in a hardcover with a clear protective overlay. The map was distributed through the USGS office, libraries, and academic institutions. The initial print run was limited to a few thousand copies, reflecting the anticipated demand for the region’s map among geological research groups and outdoor enthusiasts. Subsequent reprints were produced in response to increased interest from the public and from organizations involved in land management and conservation.
Geographic and Geologic Context
Regional Setting
Plate 62 spans an area of approximately 30 square miles (78 square kilometers) within the eastern Sierra Nevada. The sheet includes sections of Inyo County, California, and White Pine County, Nevada. The landscape is dominated by rugged mountains, deep valleys, and high alpine plateaus. Key geographic features on the plate include the peaks of Mount Clark, Mount Maclure, and the adjacent alpine ridgelines that delineate the boundary between the two states. The map also captures the valley floor of the Owens River, the watercourse that drains the eastern Sierra.
Geologic Features
The region represented by Plate 62 is geologically diverse. The Sierra Nevada is composed mainly of granitic plutons that were emplaced during the Cretaceous period. In the western portion of the plate, there are exposed granite formations such as the Cathedral Peak granite, which is notable for its large crystal size and high purity. The eastern portion of the plate features metamorphic rocks, including schist and gneiss, indicative of the tectonic forces that shaped the Sierra’s eastern margin. Fault lines, such as the Mono Basin fault, are clearly marked on the map, illustrating the tectonic activity that has continued into the present day.
Hydrology
Hydrographic detail on Plate 62 includes the Owens River and its tributaries, as well as the Owens Lake basin. The map indicates the flow direction of streams and the presence of seasonal lakes. Additionally, it captures a network of creeks that feed into the main river, including the Clark Canyon Creek and the White Pine Creek. The representation of water bodies follows USGS standards, with open areas indicating permanent lakes and shaded areas indicating seasonal ponds.
Map Characteristics
Scale and Detail
The 1:24,000 scale of Plate 62 allows for a detailed representation of features that are at least 40–50 feet in size. At this scale, contour intervals are set at 20 feet, providing a clear depiction of elevation changes and terrain ruggedness. The scale also supports the accurate placement of man‑made features such as roads, trails, and structures, which are essential for navigation and planning.
Topographic Features
Contour lines on Plate 62 are plotted at 20‑foot intervals, with isohypses labeled at 200‑foot intervals to aid in rapid reading of elevation. The map includes hillshading, which is achieved by a subtle gradient of line weights, giving the reader a visual sense of the terrain’s relief. The contour lines are continuous except where they are interrupted by features such as rivers, roads, or dense vegetation. The map also incorporates depressions, such as sinkholes and small valleys, by using interrupted or dashed lines to indicate their presence without cluttering the visual field.
Geologic Representation
Geologic features on Plate 62 are depicted using a combination of color coding and shading. Granite exposures are represented with a light brown hue, while metamorphic rocks appear in varying shades of gray. Fault lines are shown as bold dashed lines, with fault labels positioned adjacent to the line. Stratigraphic information is provided where available, with notes on rock age and composition. The map follows the USGS geologic map conventions, ensuring consistency with other maps in the series.
Hydrography
Water features are illustrated using blue shading for permanent bodies and lighter blue for seasonal ones. River paths are shown as narrow black lines, with width varying to indicate relative flow. The Owens River, being a major watercourse on the plate, is highlighted with a thicker line and accompanied by a label. Lakes and ponds are represented with open shapes, and their names are annotated in a standard font. In addition to natural water bodies, the map also includes man‑made structures such as dams, which are depicted with black rectangles.
Human‑Made Features
Transportation infrastructure on Plate 62 is marked by a network of highways, roads, and trails. Major roads, such as U.S. Route 395, are drawn as bold solid lines, whereas secondary roads appear as thinner lines. Trails are depicted with dashed lines and are labeled with their names. The map also indicates the presence of a ranger station, a small lodge, and a few cabins, each marked with distinct symbols. Public facilities such as water sources and trailheads are annotated, providing essential information for hikers and campers.
Cartographic Techniques
The cartographic rendering of Plate 62 reflects a blend of hand‑drawn and computer‑generated elements. After initial data processing, cartographers used vector‑based software to generate contour lines and symbol placement. The final map was printed using lithographic plates, which allowed for high fidelity in the reproduction of fine details. Color printing was used to differentiate between terrain types, with a limited palette that adhered to USGS guidelines. The use of line weight, color, and labeling was carefully balanced to maintain legibility while conveying complex information.
Users and Applications
Scientific Research
Plate 62 has served as a primary reference for geological studies of the Sierra Nevada. Researchers use the map to locate sampling sites, to understand fault activity, and to assess the distribution of rock types. Hydrologists have employed the map to model water flow and to analyze watershed dynamics. The high level of detail enables precise fieldwork, allowing scientists to correlate on‑ground observations with the map’s representation.
Land Management
Federal and state agencies responsible for land management in the Owens Valley and surrounding areas rely on Plate 62 for planning purposes. The map aids in assessing the impacts of development projects, such as road construction or mining activities. It also assists in the designation of protected areas, helping managers to delineate boundaries of wilderness and forest lands. The detailed hydrographic information supports water rights litigation and resource allocation decisions.
Recreational Use
Recreational users, particularly hikers, mountaineers, and anglers, benefit from the map’s clear depiction of trails, peaks, and water sources. The labeling of trail names and the inclusion of trailheads provide navigational aid. The map’s hillshading and contour lines help users anticipate elevation gain and potential hazards such as steep cliffs or avalanche zones. Plate 62 is often cited in guidebooks and online resources that promote outdoor activities in the Sierra Nevada.
Preservation and Legacy
Conservation Efforts
Since its publication, Plate 62 has been a focal point for conservation initiatives in the eastern Sierra. The map’s detailed depiction of natural and human‑altered landscapes has been instrumental in establishing wilderness boundaries. Organizations such as the Sierra Club and the U.S. Forest Service reference the map when delineating new protected zones. Moreover, the map’s representation of water bodies has supported water‑rights negotiations between California and Nevada, particularly concerning the Owens River.
Archival and Reprint History
Plate 62 has undergone several reprints and digital conversions over the decades. The original hardcovers were preserved in university libraries and state archives. Recognizing the map’s historical value, the USGS undertook a digitization project in the early 2000s, converting the plate into a high‑resolution PDF format. This digital version adheres to the same cartographic standards as the printed version, ensuring that the map’s integrity remains intact for contemporary users.
Impact on Modern Mapping
Plate 62 exemplifies the evolution of topographic mapping from manual surveying to integrated digital systems. Its creation helped establish a benchmark for the level of detail that modern maps can provide. Subsequent USGS mapping projects, such as the 1:25,000 scale maps and the Digital Elevation Models (DEMs), have built upon the methodologies and standards first refined during the production of Plate 62. The sheet’s enduring relevance underscores the importance of detailed, accurate, and user‑friendly cartographic products in understanding and managing natural landscapes.
See Also
- USGS 7.5‑Minute Quadrangle Series
- Owens River Geology
- Owens Valley
- Mono Basin Fault
- Sierra Nevada Granitic Plutons
- Inyo County Geology
- White Pine County Hydrology
- USGS Geologic Mapping Conventions
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