Santa Clara County, California · Franciscan Complex · Pajaro and Coyote basins
An evidence-graded plate of where Morgan Hill Poppy Jasper came from and where erosion should have carried it. The land is drawn in one sepia ink from federal survey geometry. The jasper is the only color on the sheet - and how hot it burns is exactly how good the evidence is, not how good the story is.
Three inks. The lithology prints sepia by hardness - young alluvium palest, serpentinite darkest. Water prints slate. Franciscan chert, the rock the material comes from, prints jasper, and so do the register sites, at whatever intensity their evidence has earned. Select any site for its dossier; a leader line will tie the two together.
Select a site on the plate, or a row in the register below, and its dossier opens here.
The three gem localities in this area look like independent corroboration. They are not. Traced back, they collapse into a single unlabeled symbol on one map - and the document underneath that symbol has never been scanned.
Three MRDS records → one 1972 CDMG delivery → one 1975 commodity summary that exists only on paper at Menlo Park.
GEM records, digitized. Where nearly every modern source
ultimately points.The chain read as a stream profile, descending left to right. Solid steps rest on tier 1 or tier 2 evidence. Dashed steps are inferred and have not been observed; the last has not been attempted at all.
A mapped fc varicolored chert body on the west side of Watsonville Road,
against the Llagas alluvium.
Chert is far more resistant than the sheared serpentinite and shale around it, so it should survive as clasts. Not observed.
Inference from lithologyEnters Llagas Creek below Chesbro Dam, so this material was never caught by the 1955 sediment trap.
Tier 1 · hydrographyGravel bars, inside bends, gradient breaks. No terrain analysis has been run on this reach yet.
Inference from processNobody from this project has stood in it. The prediction is unverified in both directions.
Field status: not visitedEvery meaningful location, including the ones that failed. Rejected sites stay in the record so the same ground is not investigated twice - they print ash-grey and struck through, which is exactly the weight their evidence carries.
| ID | Site | Sub‑watershed | Interpretation | Confidence | Access |
|---|
On a narrow sheet the ledger prints four columns. Sub‑watershed and interpretation are in each site’s dossier - select a row.
The Pajaro basin drains south to Monterey Bay; the Coyote basin drains north to San Francisco Bay. Water does not cross between them, so no single transport model links sites on opposite sides. On the plate it is the one unbroken heavy line.
But the divide near Morgan Hill is not a bedrock crest - it crosses alluviated valley floor at roughly 380-530 ft, about 2 km north of El Toro. A 1954 state report calls it an “imperceptible alluvial divide… elevation 345 feet.” Whether it held through the Quaternary is unproven, and is not assumed here in either direction.