This second volume of the Alta Toquima trilogy situates Monitor Valley archaeology within the Central Mountains Archaic, introduced here as a taxonomic equivalent to the better-known Lovelock culture, Fremont complex, and the Virgin Branch of Ancestral Puebloans. This analysis integrates Monitor Valley into the broader Intermountain West using seven multiscalar time slices that address paleoclimatic and cultural change from the Late Pleistocene/Early Holocene (pre-7000 cal b.c.) through the Little Ice Age (cal a.d. 1350–1800). This overview establishes that the loglinear relationships between two independent cultural proxies (nearly 5000 cultural radiocarbon dates and more than 47,000 time-sensitive projectile points) are highly correlated (r = 0.988) and relevant for explicating region-by-region demographic change. We hypothesize that the Intermountain West achieved (or exceeded) exponential growth throughout more than 90% of the 13 millennia spanning Paleoindian colonization through Euro-American contact. During two notable exceptions—the Late Holocene Dry Period (850 cal b.c.–cal a.d. 100) and the late 13th-century drought—human population growth fell below exponential expectations. The Late Holocene Dry Period (LHDP) was a pivotal climatic event that varied in geographic range, duration, and intensity. The 42°–40° N dipole hypothesis holds that persistent La Niña-like climatic conditions resulted in an anomalously moist northern Great Basin and exceptionally arid southwestern Great Basin, separated by an undulating dipole transition between 42° and 40° north latitude. Human demography plummeted below exponential expectations as foragers abandoned almost all settlements south of the 42°–40° N dipole, marking an intensification that shifted away from “man caves” and logistical bighorn hunting to extended family bands who created the first alpine residences at Alta Toquima. The high-elevation settlements were occupied only during the driest of the short-term xeric-mesic cycles during (and after) the LHDP. In wetter times, the alpine houses were abandoned in favor of repurposed man caves and other subalpine base camps. These syncopated intensifications began a full millennium before the arrival of bow technology into the Central Mountains Archaic. The other exception to exponential growth was the tumultuous late 13th-century drought, when the Fremont complex dissolved after a dozen centuries of farming, the Lovelock culture disappeared, and the Virgin Branch of Ancestral Puebloans collapsed—all part of the far-reaching demographic decline in the American Southwest and elsewhere across interior North America. In the aftermath of these fundamental economic shifts, changing social landscapes, and human migrations, the Little Ice Age returned to exponential growth during the challenges and windfalls for Shoshonean communities of the Intermountain West. This volume proposes and tests multiple hypotheses addressing the deep natural and cultural histories of the Intermountain West. Resilience theory proves to be an important tool in unraveling relationships between abrupt climatic and behavioral adjustments, human paleogeography, piñon pine processing, multiple meanings of abandonment, adaptation to lacustrine and desert-mountain mosaics, and shifting landscapes of ritualized practice.

Nevada lies in one of the driest parts of North America. The region has long grappled with droughts and also with extended periods in which the already dry climate aridified for decades or centuries. Here we place Nevada’s most recent statewide drought (2020 – present) in the context of historical, archaeological and paleoclimate records dating back through the Mid-Holocene. The current drought is distinct from historical droughts that impacted the state in the 1930s, 1950s, and 1970’s and 1980s. It is notably warmer than droughts of the 20th century and more spatially extensive than any of these, although the 1930s drought also impacted much of the West. The early 2020s drought is also embedded within a two-decade long dry period, raising important questions about whether it is (1) drought, a relatively short period of abnormal dryness; (2) megadrought, a longer and typically more severe period of unusually dry conditions; (3) the manifestation of aridification, a shift toward a generally drier climate because of long-term precipitation declines and/or warming; or (4) some combination of the three. A broader view suggests that at least some aspects of drought since 2020 may not be unique. Paleoclimate evidence from cave deposits, lake and meadow sediments, animal middens, dead wood and tree rings indicate that Nevada and much of the western United States experienced decadal and centennial long dry periods in the Middle Holocene (5000 – 7000 years ago), the Late Holocene, (1800 – 3100 years ago), during the Medieval Climate Anomaly (1000 – 650 years ago) and again 600 – 500 years ago. The archaeological record shows that Indigenous Nevadans responded by repeatedly adapting to changing paleoenvironmental conditions. However, some key questions about fine-scale temporal and spatial variability in the experience of drought remain. Limitations in the spatial, seasonal and temporal resolutions of climate reconstructions—and in the observational record—may obscure the evidence for short or seasonally specific wet periods within longer dry periods or spatial variability in precipitation. Nonetheless, proxy and archaeological evidence from the last 10,000 years shows that understanding and responding to drought requires viewing drought on these time spans with an appreciation for the details that appear in modern observations.

The Central Mountains Archaic began with the arrival of foraging populations in the Intermountain West about 6000 years ago. This migration coincided with the "extremely dramatic" winter-wet event of 4350 cal b.c. and the arrival of piñon pine forests in the central Great Basin. Human foragers likely played a significant role in the rapid spread of piñon across the central and northeastern Great Basin. Logistic hunters exploited local bighorn populations, sometimes serviced by hunting camps (the "man caves" such as Gatecliff Shelter, Triple T Shelter, and several others) and they staged communal pronghorn drives at lower elevations. As climate cooled and became more moist, logistic bighorn hunting gradually shifted downslope, then apparently faded away about 1000 cal b.c. Communal pronghorn driving persisted into the historic era in the central Great Basin. This volume, the first in the Alta Toquima trilogy, describes and analyzes more than 100 alpine hunting features on the Mt. Jefferson tablelands. High-elevation, logistical bighorn hunting virtually disappeared across the central Great Basin with the onset of the Late Holocene Dry Period (about 750-850 cal b.c.), giving way to an alpine residential pattern at Alta Toquima (26NY920) and elsewhere on Mt. Jefferson. Situated at almost exactly 11,000 ft (3352 m) above sea level, Alta Toquima was sited on the south summit of Mt. Jefferson (the third-highest spot in the state of Nevada), where at least 31 residential stone structures were emplaced along this steep, east-facing slope. When first recorded in 1978, Alta Toquima was the highest American Indian village site known in the Northern Hemisphere. This volume discusses the material culture, plant macrofossils, vertebrate fauna, and radiocarbon dating for Alta Toquima. Bayesian analysis of 95 14C dates documents an initial occupation of Alta Toquima at 1370-790 cal b.c., with the sporadic settlements persisting until immediately before European contact. These alpine residences are the most dramatic examples of the intensified provisioning strategies that began in the Central Mountains Archaic about 3000 years ago, broadening the diet breadth to include plant and animal resources previously considered too costly. The oldest summertime residence at Alta Toquima correlates with the onset of Late Holocene Dry Period (LHDP) aridity (~750 cal b.c.), and these houses were episodically occupied only during the driest intervals throughout the next 1500 dramatic years of abrupt climate change. During the intervening wetter stretches, Alta Toquima was abandoned in favor of subalpine basecamps. This sequenced intensification predated the arrival of bow technology in the central Great Basin by more than a millennium. Exactly the opposite sequencing took place a few miles to the north, when Gatecliff Shelter was abandoned during LHDP aridity--precisely when the first summertime settlements appeared at Alta Toquima. This pattern reversed again when lowland habitats became sufficiently well watered to again support summertime patches of seeds and geophytes (~150 cal b.c.-cal a.d. 100). Alta Toquima families responded by abandoning (temporarily) their alpine summertime camps to repurpose former "man caves" like Gatecliff and Triple T shelters into family settlements. The Monitor Valley sequence documents several syncopated lowland-alpine, wet-dry reversals, reflecting an adaptive diversity that spanned more than two millennia. The drought terminating cal a.d. 1150 devastated much of the western Great Basin and American Southwest, but its impact was less severe in central Nevada. Although subalpine sites were again abandoned during the drought buildup that peaked in the mid-12th century, summertime occupation of Alta Toquima became more commonplace, although it increased notably during the ~cal a.d. 1200-1400 aridity and persisted throughout the Little Ice Age.