12345
CRN-2026-04rec. 94%
  1. 0002026
  2. 0602026
  3. 1802025
  4. 3402023
  5. 5002022
  6. 6602019
  7. 8302017
  8. 9002016
CRN-04-B0, 0 to 60 centimetres, 2026. Surface: Weathered surface, worked daily.CRN-04-B1, 60 to 180 centimetres, 2026. Loose fill: Unconsolidated fill, added each morning.CRN-04-B2, 180 to 340 centimetres, 2025. Interbedded: Interbedded pairs, contact holds both ways.CRN-04-B3, 340 to 500 centimetres, 2023. Laminated: Fine laminae, legible throughout including scans.CRN-04-B4, 500 to 660 centimetres, 2022. Graded: Graded bedding, every earlier grain retained.CRN-04-B5, 660 to 830 centimetres, 2019. Unconformity: Buried contact, re-exposed on demand.CRN-04-B6, 830 to 900 centimetres, 2017. Bedrock: Plain markdown basement, no cement.CRN-04-B7, 900 to 940 centimetres, 2016. Core catcher: Base of recovery, terms of the sample.
  1. SurfaceCRN-04-B0
  2. Loose fillCRN-04-B1
  3. InterbeddedCRN-04-B2
  4. LaminatedCRN-04-B3
  5. GradedCRN-04-B4
  6. UnconformityCRN-04-B5
  7. BedrockCRN-04-B6
  8. Core catcherCRN-04-B7

CRN-04-B00–60 cm2026Weathered surface, worked daily

base 940 cm

0–60 cm2026CRN-04-B0

Weathered surface, worked daily

A decade of notes, still legible at depth.

Cairn is a note-taking app for people whose notes outlast the work they were written for. Every note is a markdown file on your own disk. Links form as you type. And the notes you buried years ago come back up when they touch what you are writing today.

Download for macOSSee what a vault looks like on disk
surface
0 cm — today
base
940 cm — Mar 2016
recovery
94% of drilled length
0   10   20 cm  ·  core CRN-2026-04 ·  logged 25 Jul 2026
60–180 cm2026CRN-04-B1

Unconsolidated fill, added each morning

The day starts with a note already open.

Launch Cairn and today’s note is there, dated and empty. It catches whatever arrives before you know where it belongs. Most of it stays loose. Some of it gets moved down into something you keep.

2026-07-25 · Saturdaydaily note
  • call back R. Okonjo about the transcript before Friday
  • kiln held 1040 °C for 40 min — cone 6 bent flat, cone 7 upright
  • compare estuary core photos against the 2019 set
180–340 cm2025CRN-04-B2

Interbedded pairs, contact holds both ways

Type two brackets. The link holds from both ends.

Type [[ and pick a note. Cairn writes the link where you are standing and records the backlink on the other note at the same moment. Nothing to file afterwards, and no way to end up with a link that only points one way.

Why the 1854 cholera map workededited 11:04

Snow did not persuade anyone with the dots. He persuaded them with the pump. Compare the way we read [[Estuary sediment cores]] — same trick, different medium.

[[ ]]
Estuary sediment coresnot edited since 2025

Linked from

  • Why the 1854 cholera map worked
  • Bridge deck expansion joints
340–500 cm2023CRN-04-B3

Fine laminae, legible throughout including scans

Search reads the scans as well as the typing.

Search covers every note in the vault, and it does not stop at text you typed. Scanned PDFs and photographed pages are read too, so a phrase from a handout you filed in 2019 comes back alongside everything else.

pump handle4 notes · 0.02 s
  • Why the 1854 cholera map worked…removing the pump handle ended the outbreak that was already ending…2023 · 390 cm
  • Interview — R. Okonjo, 12 Marscan · p. 4…she drew the pump handle on the whiteboard and left it there for a week…2021 · 610 cm
  • Reading — Seeing Like a Statescan · photo…margin note, my handwriting: “the pump handle is the only legible act”…2018 · 750 cm
500–660 cm2022CRN-04-B4

Graded bedding, every earlier grain retained

Every version stays, on every device.

Each note keeps its own history — every save, timestamped, next to what it replaced. Open any earlier state and copy a paragraph back out. The same vault opens on your phone, so a correction made on a train is the same file you edit at your desk.

Sourdough: hydration log14 versions
  • 2026-07-19 08:12current · 82% at 26 °C
  • 2026-03-02 21:40+ winter kitchen numbers
  • 2024-11-11 07:5578% at 21 °C
  • 2022-06-04 19:03first entry
One vault, two machinessame files

Sync is optional. Without it the vault still opens, from the folder it has always been in.

660–830 cm2019CRN-04-B5

Buried contact, re-exposed on demand

Resurface brings the buried layer up.

While you write, Cairn looks below the surface for notes you have not opened in a year or more that touch what is in front of you. It does not rank you or nag. It sets two or three old notes at the foot of the page with the date you last opened them, and leaves the judgement to you.

Estuary sediment cores0 cm · writing now

Three cores from the north bank. The 2019 handling notes are the part I keep half-remembering — something about the tube temperature before extrusion.

resurfaced from depth
  • 690 cmKiln temperature curvesshares: extrusion temperature, holding timelast opened Feb 2019
  • 745 cmBridge deck expansion jointsshares: thermal expansion in confined tubeslast opened Aug 2018
  • 812 cmField recording — dawn chorusshares: north bank, tide table, same fortnightlast opened Nov 2017

Dismiss a suggestion and it will not come back for that note. Turn Resurface off entirely in settings.

830–900 cm2017CRN-04-B6

Plain markdown basement, no cement

Markdown files, in a folder you already own.

A vault is a folder. Each note is a .md file you can open in any editor, back up however you already back things up, and read on a machine that has never heard of Cairn. It works with no network. If you stop paying us — or we stop existing — the notes are still there and still readable.

~/vault4,118 files · 61 MB
  • kiln-temperature-curves.md6 KB
  • why-the-1854-cholera-map-worked.md11 KB
  • mnemonics-from-the-ad-herennium.md9 KB
  • letterpress-lockup-diagram.md3 KB
  • daily/2026-07-25.md1 KB
  • .cairn/history/versions, also plain text
900–940 cm2016CRN-04-B7

Base of recovery, terms of the sample

One vault free. Sync is $8 a month.

The app is the same either way. Paying moves your files between your own machines; it does not unlock features or hold your notes anywhere you cannot reach them.

One vault

Free · forever

  • Unlimited notes on one device
  • Links, backlinks, daily note
  • Search across scans and images
  • Version history
  • Resurface
Download for macOS

Syncoptional

$8 / month

  • Everything in One vault
  • The same vault on desktop and phone
  • End-to-end encrypted transfer
  • Unlimited vaults
  • Cancel and keep every file
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Sample archive record

Core
CRN-2026-04
Interval
0–940 cm
Recovery
94%
Datum
surface = 25 Jul 2026
Base
940 cm = 03 Mar 2016
Beds logged
8
Storage
~/vault · plain markdown
Logged by
Cairn
DownloadFile formatVersion historyResurfacePricing

Cairn keeps nothing you cannot read without us. Notes stay on your disk, in the folder you chose, in the format you can grep.