The Devil Point obsidian source is located in Oregon's central Western Cascades approximately eight kilometers northeast of Mt. Jefferson. Situated in the Mt. Jefferson Wilderness Area, the source is accessible only by trail in the late spring, summer, and fall; during the rest of the year, trails and local roads are typically blocked by snow.

The first mention of obsidian in the Devil Point area in the geologic literature was by Priest and Woller (1983) in their description of the area located immediately west of the source. Several other geologic investigations in the area fail to mention the presence of any obsidian. At the primary Devil Point source area, obsidian nodules up to about eight centimeters in diameter occur as surface float. The zone in which the nodules originate rests on a light-colored ashy deposit containing pumice and small fiamme fragments. The zone is directly overlain by flow-banded rhyolites. The occurrence of obsidian nodules decreases rapidly away from the source and nodules were rarely noted more than 100 meters from the primary source area. Nodules of obsidian that are geochemically correlated with the Devil Point source also occur several kilometers south of the primary source in the gravels of Grizzly Creek.

Geologic Age: Geologic mapping by Priest et al. (1987) places the primary Devil Point source within the upper Miocene - Tp unit - the Lavas of Triangulation Peak.

Petrographic Characteristics: The color of obsidian from the Devil Point source is most commonly black to dark gray and occasionally medium gray. The glass is typically uniform in color or is distinctly banded and is opaque to nearly opaque when a 1 mm-thick flake is held to a light source. The surface luster of a freshly broken surface of glass is vitreous; the surface texture is porphyritic and visibly marked by the presence of abundant inclusions set in a glassy groundmass. Small phenocrysts are very abundant and may be visible to the naked eye although most are less than 1 mm in length. These small phenocrysts were observed in every specimen of source material analyzed by Skinner (1997). Small spherulites up to 6 mm in diameter are also commonly found in the glass. In general, obsidian from the Devil Point source is visually distinguishable from other sources of obsidian that occur in western Oregon.

Chemical Composition: The trace element composition of geologic samples (N=34) from the Devil Point source is reported by Skinner (1997):

Prehistoric Use: The existence of the Devil Point source has only been recently known to Oregon archaeologists (Hughes 1986b). The spatial patterning of archaeological sites with artifacts correlated with the Devil Point source indicates that use was restricted primarily to the immediate region surrounding the source. The shaded relief trend surface map at the top of the page and the distribution and trend surface contour and maps located immediately below clearly illustrate this localized source use pattern. Given the less-than-ideal quality of the glass and the presence of other regionally-available high-quality obsidians, this is hardly surprising.

Analysis of the spatial patterns of Devil Point obsidian that are revealed by geochemical and obsidian hydration studies of artifacts suggest the following summary conclusions concerning prehistoric use of the source (Skinner 1997:27-28):

1. Prehistoric use of Devil Point glass was restricted almost entirely to the local region surrounding the source.

2. Prehistoric source use was limited primarily to the Western Cascades of Oregon although there is some limited evidence for trans-Cascade procurement from groups east of the central Cascade Mountains.

3. Given the somewhat uneven distribution of the characterized archaeological sites used in this analysis, the boundaries for prehistoric source use appear to be quite well-defined.

4. The high frequency of Devil Point obsidian in the form of debitage, even at sites near the source, strongly suggests a largely utilitarian role for the use of the glass.

5. Except in the immediate source vicinity, artifacts made from Devil Point glass typically co-occur with those from other High Cascades and central Oregon source, most notably Obsidian Cliffs, Newberry Volcano, and Inman Creek.

6. The obsidian was primarily directly procured at the source, a strategy embedded within the normal seasonal activities and procurement range of groups in western and central Oregon.

7. The magnitude of the Devil Point procurement was relatively small compared to other more dominant obsidian sources in western and central Oregon.

8. The relationship of source use with the distance to the source (distance-decay relationship) is relatively predictable; the maximum distance that Devil Point obsidian has been identified in an archaeological context is about 90 km.

9. The distribution of hydration rim values for Devil Point artifacts suggests that the source was used for a temporally restricted period ranging from perhaps the Middle to Late Archaic periods through early historic to protohistoric times.