Bibliographic record
Abstract
Fossils representing species living on wave-swept, open rocky shores are seldom found preserved in the stratigraphic record. This report documents the separate occurrences of the bivalves Mytilus californianus and Petricola carditoides found associated with the Pleistocene-Cretaceous nonconformity at Punta Cabras on the Pacific coast of northern Baja California, Mexico. A pocket beach deeply incised in the steep andesite coast at Punta Cabras is the repository of both a modern beach coquina and a 3.36-meter thick, fossil shell bank consisting predominantly of transported M. californianus. Analysis of the modern beach across an onshore-offshore transect helps explain distinct stratigraphic cycles in the homologous fossil deposit. These cycles may be related to modest changes in sea level during the last interglacial period (oxygen isotope stage 5a), to extraordinary storm events, or to local uplift. At another nearby locality, fossils of P. carditoides are preserved in borings directly penetrating a gentle andesite ramp. The ramp is also partially encrusted with fossilized red coralline algae. The Mytilus deposit, with its associated gastropod and barnacle species, signifies a transported death assemblage but the Petricola population represents part of an in situ community.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.005 | 0.002 |
| Meta-epidemiology (broad) | 0.003 | 0.003 |
| Bibliometrics | 0.004 | 0.003 |
| Science and technology studies | 0.003 | 0.004 |
| Scholarly communication | 0.005 | 0.009 |
| Open science | 0.005 | 0.006 |
| Research integrity | 0.008 | 0.004 |
| Insufficient payload (model declined to judge) | 0.992 | 0.994 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; the direct Gemma label and the distilled Codex classifier agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".