California Department of Resources Recycling and Recovery (CalRecycle) 

Solid Waste Facilities Engineering Support Services

The Importance of Landfills on Paleontology and the Need For Expediting the Removal of Fossils

Significance of Landfills As Sources of Fossils

Physical Aspects:


  • Landfills are distributed throughout California from Oregon to Mexico.
  • They are located from the Pacific coast to the eastern slopes of the Sierra Nevada.

Numbers: There are over 188 landfills operating within California (CIWMB Solid Waste Information System Database as of April 1999).

Physical Dimensions:

Landfills range from 1 acre to 2,290 acres in size.

Landfill Depths can attain over 100 feet, providing for a long, continuous stratigraphic record to be exposed.

Volumes of material in soil moved or removed can range in millions of cubic yards.

These volumes can be removed in relatively short periods of time.

Time Durations:

Landfills can operate for long periods of time 5 to 100 years or longer.

  • Provides for long-term research plans.
  • Massive volumes of material can be removed over the lifetime of the landfill.
  • Materials that would take a lifetime with manual labor can be excavated within days.
  • Repeated visits to a site can be carried out until closure, which can be years away.

Variety of Locations:

The 188 landfills scattered across the state provide potential for species geographic distribution data.

Temporal distributions can be researched as species occur in different age deposits, providing insight into longevity of species.

Fossils from a broad geologic time span and paleoenvironments are potentially accessible as landfills occupy every geologic province in California.

Currently, 28 landfills have yielded significant assemblages of fossils.

Ten sites have yielded significant vertebrate assemblages:

  • 7 Land vertebrate assemblages.

Megavertebrates: Camelidae, Oreodonts, Equus.
Microvertebrates: Squirrel, pocket mouse, shrew.

  • 6 Marine vertebrate assemblages.

Smaller bony fishes; barracuda, surgeonfish.
Cartilaginous fishes; sharks, rays.
Whales, dolphins, sea lions, manatee-like, and walrus-like mammals.

In addition, 15 sites have yielded marine invertebrate assemblages.

  • Molluscs: Gastropods, Pelecypods, Cephalopods.
  • Echinoidea: Urchins, sand dollar.
  • Corals, Annelid worms, Foraminifera.
  • One very rare, diverse faunal association of marine vertebrate, invertebrate, microinvertebrate, land and marine plant fossils found in a single assemblage - Puente Hills LF

Significant Discoveries from landfill finds, including:

New Species:

  • Iguanid lizards, mice, didelphid marsupial - Frank R. Bowerman LF
  • Paradjidaumo, Namatomys, Simimys, Simimeryx heliscomys, Macrotarsius roederi (Primate) - Simi Valley LF
  • Great White Shark (Carcharocles megalodon): (rarely found) - Santiago LF

Extended species distributions:

  • Eurhinodelphidae: Dolphin found at F.R. Bowerman LF extends its living (geographic) range several hundred miles SW of its current known range.
  • Nautiloid cephalopod: first found in California F.R. Bowerman LF. Expands from W. Pacific, to Eastern Pacific region.
  • Smaller vertebrates: more common than once realized - Simi Valley LF

Extended temporal distributions:

  • Didelphid marsupial specimen extends N. American age range.
  • Baleen whale skeleton - First reported in Sycamore Canyon fm.
  • Crocodile - Oldest recorded for the Sespe Fm. - Simi Valley LF
  • Discovery of youngest known record of genus Eohaplomys (beaver).

Better understanding of paleoenvironments:

  • Santiago LF - Indicates floodplain environments.
  • F.R. Bowerman LF - Marsh environments and accompanying shallow bays, sandy beaches and rocky areas.
  • Signs at Simi Valley LF - point to a tropical climate with intermittent flooding and seasonal drought.
  • Signs of cool climate Repetto Fm - Puente Hills LF

Better age-dating of formations:

  • Microvertebrates’ rapid evolution provides finer dating of formations.
  • Irvington Antelope and Armbrusters Wolf found at Fairmead site firmly date the sediments there.

Improved understanding of known species, paleoenvironments, etc:

  • Pachycetus: whale skeleton provided new information on its sketchy record.
  • New finds of rare known species: Wolf Eel and Mantis Stabbing Shrimp - Prima Deshecha LF.
  • Rare, or once considered absent, species of lizard (Paleoxantusia) and shrew-like insectivores; Centetodon, Batodonoides, Proterixoides, and first bats - Simi Valley LF.
  • Accurate representation of species population ratios - Fairmead LF.

These programs and legislation provide protections for paleontological resources:

  • National Historic Preservation Act (16 USC 470 Et Seq.).
  • The Antiquities Act of 1906.
  • The National Landmark Program, 1962.
  • Surface Mining and Reclamation Act, 1977 (when dealing with mining and gravel extraction sites).
  • Federal Land Management and Policy Act 1976.
  • National Environmental Policy Act 1969.(42 USC 4321-4347).
  • In California:
    • California Environmental Quality Act (CEQA).
    • California Public Resources Code, Sec. 5097.

Importance of a Prepared Plan for Retrieval of Fossils:

  • Avoids delays to operator for preparation of disposal site—their main goal.
  • Improves operator’s confidence in the procedure the next time a locality is discovered.
  • Assures specimens will be retrieved.
  • Assures compliance with state and federal regulations (CEQA, etc).

Plans for Future Statewide Contact Listing and Policy

  • CalRecycle Policy/ LEA Advisory for procedures of operator contact and remediation based on current working models.
  • Reference list of institutions, qualified individuals for contact by operators and Local Enforcement Agencies. Available through CalRecycle, for future needs in Landfills inexperienced with the process.
  • Study, resolve shortcomings still present in current process. Work with experts in the process for future projects.
  • Coordination with CEQA requirements.
  • Informational database in SWIS and web page for research use.


For providing information on the landfills:

  • Diana Wier—RMW Paleo-Associates
  • Mark A. Roeder—Paleoenvironmental Associates
  • E. Bruce Lander—Paleoenvironmental Associates
  • Robert G. Dundas—Museum of Paleontology, U.C. Berkeley
  • Kathleen Springer—San Bernardino Co. Museum

Paleontological Resources Home

Last updated: May 12, 2005
Closure and Technical Services,
Mike Wochnick: (916) 341-6318