PCAS General Meetings

Monthly lecture meetings feature noted archaeologists and anthropologists who provide insight into a variety of topics. Lecture meetings are held at the Irvine Ranch Water District Community Room, 15500 Sand Canyon Avenue (between the I-5 and I-405) in Irvine, on the second Thursday of each month, at 7:30 pm. Meetings are free and open to the public. See vicinity and detail maps of PCAS meeting location.

The Irvine Ranch Water District makes its facilities available for use by residents and nonprofit organizations merely as a public service, but does not, by allowing this use, endorse or support the purpose of the event or its sponsor. .

Many past PCAS lectures are available on the PCAS YouTube channel.

PCAS Zoom Meetings  


May 9, 2024

In-Person and Zoom Meeting (Speaker will not be present at the in-person meeting.)

Dr. Patrick O'Grady

Evidence for 18 ka Human Occupation at Rimrock Draw Rockshelter, Harney County, Oregon

Rimrock Draw Rockshelter (35HA3855) is a small and shallow rockshelter located in Harney County, Oregon at the north edge of the Great Basin. Situated in wide-open sagebrush steppe country, the location looks much like a thousand other nearby places where one might expect to find stone tools dating from the mid- to late-Holocene. However, the archaeological record at this site ends around 7,000 years ago, shortly after the cataclysmic eruption that formed Crater Lake from Mount Mazama, and human occupation of the site begins much earlier. Dates of 18,000 to 17,000 years before present have been obtained through high precision Accelerator Mass Spectrometry radiocarbon assays (AMS14C) on Camelops and Bison tooth enamel fragments collected from deeply buried archaeological deposits. The teeth are associated with stone tools and chipping debris indicating human contemporaneity at the site. Other evidence suggests that several genera of Pleistocene herbivores were butchered and consumed there. This presentation will include an overview of fieldwork at the rockshelter to contextualize the provenience of the dated enamel fragments.

Dr. Patrick O'Grady earned his BS, MS, and Ph.D. from the University of Oregon and worked for their Museum of Natural and Cultural History from 2005 until 2023. Before that, he worked for the Oregon Department of Transportation as a highway archaeologist. He is currently the District Archaeologist and Tribal Liaison for the Burns District Bureau of Land Management in southeastern Oregon where much of his research has been centered. Dr. O’Grady’s focus over the years has been on hunter-gatherer adaptations, Paleoamerican archaeology, geophysical field applications, and zooarchaeology, including the development of a substantial comparative osteological collection for the University of Oregon.


June 13, 2024

In-Person and Zoom Meeting (Speaker will not be present at the in-person meeting.)

Dr. Gregory Haynes

Current Research Directions for Prehistoric Ceramics in the Southern California Deserts

Archaeologists have long used pottery to identify what prehistoric cultures lived at a site – its cultural affiliation -- and when these cultural groups were there – its temporal affiliation. Ceramics in the California deserts have proven less than useful for establishing cultural and temporal affiliations because they are primarily plain wares that lack the kinds of diagnostic markers that can be systematically and consistently tracked through space and time. This is unlike the American Southwest where distinctive decorations, coupled with pastes and tempers, have been spatially and temporally delimited, and can therefore be used as highly sensitive culture-historic markers. This talk will discuss the problem with using plain wares to establish cultural and temporal affiliation at archaeological sites and emerging solutions that may resolve some of these problems.

Plain ware pottery, however, was made to accomplish specific subsistence tasks for prehistoric families. Some pots were used to store food and water, others for processing and cooking foods, while still others were related to serving and consumption. One way to understand household technologies and subsistence activities is by determining the composition and size of ceramic vessel assemblages used by prehistoric households. How were these vessels made; what kinds of vessels were used by households during their day-to-day activities; and, what do the different types of vessels tell us about how these people made a living in the distant past? The second part of Dr. Haynes’ talk will focus on my own research into pottery manufacture and whole vessel forms from around now extinct Lake Cahuilla.

Dr. Greg Haynes has been a practicing archaeologist since 1985 and over his career has worked in the public, private, and university sectors. Greg specializes in the hunter-gatherers of the Great Basin and ancestral Puebloan agriculturalists of the American Southwest. He obtained a Ph.D. from the University of Nevada, Reno, in 2004 studying a Paleoindian complex in the northern Armargosa Desert. He has conducted a wide variety of investigations in Nevada, Utah, and Arizona, including pedestrian inventory, archaeological and architectural documentation, surface collection and subsurface testing, data recovery, and even some geophysical surveys. Recent career highlights include research on a large pictograph complex at Fort Hunter Liggett in Monterey County, where he obtained portable X-ray florescence data on approximately 100 of the images, development of a monograph for the BLM on California desert ceramics (with Dr. Karen Harry), and analyses of Patayan Tradition ceramics from around now extinct Lake Cahuilla.


No meetings in July and August


September 12, 2024

Dr. Carolyn Boyd


October 10, 2024

David Lee

Seeing Rock Art through the Eyes of the Elders