A diverse late-glacial (Mackinaw Phase) biota from Leamington, Ontario
Bibliographic record
Abstract
A sand pit at Leamington, Ontario, in southeastern Essex County in the southernmost part of Canada, has yielded many taxa of fossil animals and plants that are dated over 13 000 BP. The fossils are of both terrestrial and freshwater origin, and comprise a surprisingly diverse but coherent assemblage of molluscs, ostracodes, Chironomidae, Coleoptera, Turbellaria, Trichoptera, and a few fish bone fragments. This is the oldest known postglacial occurrence in Ontario for all animal groups. Paleoenvironments indicated by the taxa range from boreal forest to tundra; taxa are an in situ assemblage with little transport or reworking. Although this site has yielded the richest fossil record of this age yet found in Ontario, previous finds at a few sites on the north edge of the eastern Erie basin and in the southern Huron basin indicate plants were well established in southwestern Ontario by the time of the Mackinaw Phase interstadial when lowered lake levels likely facilitated their arrival from land areas to the south. This discovery greatly improves the prospects of finding fossils of this age even though the known record is still extremely limited. The site represents fortuitous preservation and discovery, and amply demonstrates that glacial lakes of this time, when much of the last ice sheet was still in existence, were far from barren of life and that the migration of biota into the area was quite rapid during ice retreat.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.004 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
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; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".