New Jersey
Big Brook Preserve
An East Coast unicorn: a Cretaceous fossil creek in the woods. Mosasaur teeth, ancient sharks, and even rare amber - none of which need the ocean.
Phoning NOAA for the tide chart…
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Geology
FormationsNavesink Formation, Mount Laurel Formation
EpochsLate Cretaceous
Age~70 million years
Star speciesSqualicorax + Mosasaurus tooth
Technique
Sift gravel bars in the stream. Bring a 1/4 inch sifter, kneeling pad, water shoes. After heavy rain is best - fresh exposure.
Access
Big Brook Preserve, Marlboro Township NJ. FREE. Park at the Hillsdale Rd lot.
Legality & ethics
Park rules: hand tools only, no shovels/picks, leave no trace. Casual surface collecting permitted; no commercial digging.
Hazards
- Ticks (year-round) - DEET + tuck pants
- Slippery banks
- Spring high water - never wade alone after storms
Insider tips
- Right after a heavy rain (24-48h later) is gold - fresh gravel exposed
- Look for the dark glossy black teeth against tan gravel
- Belemnites (squid pencils) and rare bits of amber appear here too
Shark teeth findable here
Trophy = headline find · Rare = real score · Uncommon = some trips · Common = most trips.
Also findable here
The beachcomber's bonus round — what else the geology gives up.
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