The purpose of this guidebook is to summarize the geology and mineral development history of the Salton Sea Area and to relate that geology and history to the evolution of other resources and scientific disciplines. REPORT ORGANIZATION Part 1: TEXT FOR FIELD TRIP GUIDEBOOK Part 2: AREA MAPS (Maps A1 to A16) FOR FIELD TRIP GUIDEBOOK These maps are at 1:50.000 scale and adapted from the Regional Geologic Mosaic. They are tabloid size (11" x 17"). Part 3 of this paper are the Regional Maps. They are designed to be printed on Arch E size paper (32" x 46"). -Map B: Regional Geology (USGS) 750K -Map C1: Regional Geologic Mosaic (various original scales) -Map C2: Regional Geologic Index Map -Map D: Regional Mineral Resources -Map E: Regional Environmental Resources -Map F: Regional Land Status and PLSS Part 4: APPENDICIES Part 4 of this paper are the data appendices. A. MINES B. THERMAL SPRINGS AND WELLS Part 5: MINE DESCRIPTIONS AND SUMMARY Part 5 of this paper is a set of separate articles for each producing mine, past producing mine or mineral occurrence of special interest in the study area. This summary and alphabetical listing has URL links to Academia.com.

Colorado Desert archaeological studies over the last 20 years are reviewed to discuss how some of the major research issues pertaining to the region have, or have not, been successfully addressed. Regional culture history and adaptation to environmental change have been the particular focus of many studies that are not widely known outside the local CRM community. Among the key questions are defining an early man phase of occupation, characterizing the Paleoindian and Archaic period occupations, and interpreting Late Prehistoric adaptations to the infilling and final recession of Lake Cahuilla.

Colorado Desert archaeological studies over the last 20 years are reviewed to discuss how some of the trmjor research issues pertaining to the region have, or have not, been successfidly addressed. Regional culture history and adaptation to environmental change have been the particular focus of many studies that are not widely known outside the local CRM community. Among the key questions are defining an early man phase of occupation, characterizing the Paleoindian and Archaic period occupations, and interpreting Late Prehistoric adaptations to the infilling and final recession of Lake Cahuilla.

For more than a century, it has been recognized that an immense freshwater lake filled much of the Coachella and Imperial valleys very late in the region's prehistory. Archaeologists have attempted to define and interpret this phenomenon. When was the lake present, and when did it disappear? How had Native Americans adapted to the opportunities and challenges created by the presence of the lake? How had they responded to its disappearance? The following study looks at those questions, partly from the perspective of investigations at a single archaeological site-the Elmore Site-and partly from the gradually accumulated body of regional scholarship.

For more than a century, it has been recognized that an immense freshwater lake filled much of the Coachella and Imperial valleys very late in the region's prehistory. Archaeologists have attempted to define and interpret this phenomenon. When was the lake present, and when did it disappear? How had Native Americans adapted to the opportunities and challenges created by the presence of the lake? How had they responded to its disappearance? The following study looks at those questions, partly from the perspective of investigations at a single archaeological site-the Elmore Site-and partly from the gradually accumulated body of regional scholarship.

Over 300 years ago, when the hunter-gatherer bands living along San Felipe Creek and the shoreline of Lake Cahuilla in Borrego Valley saw the waters retreat, they probably were not too concerned. Their oral traditions told of such events and of the water rising again, bringing with them the wealth of natural resources that made life so easy. But the waters failed to return. The marshes and sandbanks teaming with fish and waterfowl were replaced with a desert of creosote and bursage). The inhabitants found their wetland habitat restored, however, by a rare coincidence of geology, hydrology, and geography that formed San Sebastian Marsh. For the next 200 years or more these hunters and gatherers integrated the oasis-like marsh environment into their annual schedule of resource exploitation.