Rockhounding.org

Elm Lake Spillway

Brown County, South Dakota
Directions
Next site in South DakotaMound City · 74 mi

Can I collect here?

Pro
See who owns this land and whether it is claimedPro shows the owner, the claim on this spot and every claim within a mile.
Read the collecting rules by land type

Based on our latest records, with claims updated from the BLM on Oct 9, 2026. Land and claims can change quickly, so check before you go.

Minerals on record here

1 mineral

Recorded here: fossil.

64 miLisbonQuartz Gemstone, teredo petrified wood74 miMound CityPetrified Wood, opal80 miTappenAgate, chalcedony, jasper, fossil

More fossil sites in South Dakota

See them all

More sites in South Dakota

View all South Dakota sites
The Market

New on the Market

Native American arrowheadNative American arrowhead$20cubedmoons3Browse the Market

Found something here? List it for sale

About Elm Lake Spillway

Elm Lake Spillway is a fossil collection site in Brown, South Dakota, cataloged in the Paleobiology Database. Fossils here come from the Pierre Shale, dated to the Campanian (83.6–72.2 million years ago). The depositional environment is recorded as marine indet. Documented finds include Mosasaurus missouriensis, Baculites compressus.

Geologic setting

Formation
Pierre Shale
Geologic interval
Campanian
Age
83.6–72.2 Ma
Depositional environment
marine indet.
Recorded occurrences
2
Locality notes

From Russell: "from NW 1/4, NW 1/4 sec. 33, T127N, R64W, spillway of Elm Lake 10 miles W of Fredrick, Brown county, South Dakota" (note: these township and range coordinates do not match the given description and appear to be one range to the east)\r\nFrom Martin: "the spillway of Elm Lake 10 miles west of Fredrick, South Dakota, Brown County in NE 1/4 of NE 1/4 of sec. 6; T. 127 N; R. 64 W." (note: though these given coordinates differ from those reported in Russell, they also plot out to be one range too far to the east, not agreeing with the written description or the location of the lake.)

Fossils found here

Mosasaurus missouriensis
Reptilia · Mosasauridae
Baculites compressus
Cephalopoda · Baculitidae

Records and references

Data: Paleobiology Database collection 107779 (CC BY 4.0) — view the source record

Getting there

No directions yet.

How hard is it?

Getting there
– / 5
Finding anything
– / 5
Votes
0

Trip reports

No trip reports yet.

Questions about Elm Lake Spillway

Can you collect at Elm Lake Spillway?

It depends on who owns the land and whether a mining claim covers it. BLM land usually allows hand collecting for personal use, national parks allow none, and private land needs the owner’s permission. Pro members see the owner and any claims at this spot.

What minerals are found at Elm Lake Spillway?

Fossil.

Comments

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

No comments yet.

What to bring

The whole kit
  • Estwing E3-22P Rock PickThe industry-standard 22oz geological hammer. One-piece forged steel with shock-reduction grip.See it on AmazonCompare picks
  • Clear Anti-Fog Safety Glasses (4 Pack)Adjustable, anti-fog lenses for clear vision in any conditions.See it on AmazonCompare picks
  • Watertight Medical KitCompact, waterproof first aid kit with bandages, moleskin, and field essentials.See it on AmazonCompare picks
  • Northwest Treasure Hunter's Gem and Mineral GuideWhether you're digging for the first time or are an experienced rockhound or "prospector," with a simple rock hammer and...See it on Amazon

As an Amazon Associate we earn from qualifying purchases.

Source: Paleobiology Database.