shark infested waters - 1 Mile paddle

Post Oak Creek in Sherman, Texas, offers one of the most unusual paddling and fossil-hunting experiences in North Texas. This short, shaded creek winds through an exposed ancient oyster shell bed, preserving the remnants of a prehistoric inland sea that once covered the region. Though the paddle distance is only about one mile, the depth of history here is immense.

Thanks to heavy tree cover and consistent spring influence, the creek maintains a cool temperature near sixty degrees year-round. Even in summer, the air feels noticeably cooler as paddlers enter the shaded corridor, where sunlight filters through leaves and reflects off pale fossilized shells embedded in the banks.

During the Late Cretaceous period, roughly 100 to 66 million years ago, North Texas lay beneath a warm, shallow sea connected to the Western Interior Seaway. Marine life thrived here, including vast oyster reefs that once formed the sea floor. Over millions of years, these reefs fossilized and were later exposed as water receded and erosion carved the creek channel.

Today, the fossilized oyster shell bed rises dramatically along Post Oak Creek. In some places, the layered shells tower nearly ten feet above paddlers’ heads, forming pale walls that feel more canyon than creek. These formations are not loose debris but solidified reef structures, preserved where they formed.

One of the most common questions asked on this paddle is simple: What kinds of sharks lived here?
The answer is both impressive and well-documented.

Ptychodus
A highly specialized shell-crushing shark, easily identified by its broad, flat, ridged teeth. Ptychodus fed on oysters and other hard-shelled marine life, which explains why its teeth are frequently found within and around the ancient oyster reef beds that line Post Oak Creek.

Squalicorax (Crow Shark)
A medium to large predatory shark known for its triangular, serrated teeth. Squalicorax was an opportunistic hunter and scavenger, common throughout the Western Interior Seaway, and is one of the most frequently recovered sharks from North Texas fossil deposits.

Cretoxyrhina (Ginsu Shark)
One of the apex predators of the Cretaceous seas, Cretoxyrhina reached lengths comparable to modern great white sharks. Its thick, blade-like teeth were designed for slicing flesh, and while less common, these teeth are highly prized finds when they appear.

Cretalamna
An ancestral form related to modern mako and great white sharks, Cretalamna produced slender, sharply pointed teeth suited for fast-moving prey. These teeth are common in shallow inland sea deposits and represent one of the dominant mid-level predators of the time.

Scapanorhynchus (Goblin Shark Relative)
An extinct member of the goblin shark family (Mitsukurinidae) and a direct ancestor of the modern goblin shark. Scapanorhynchus teeth are long, narrow, smooth-edged, and often brownish in color, adapted for impaling soft-bodied prey in shallow marine environments. These are the slender, needle-like teeth frequently found in Post Oak Creek and are often informally referred to as “goblin shark teeth.”

Odontaspis-like Sand Tiger Shark Ancestors
Recognized by their narrow, spike-like teeth, these sharks hunted smaller fish in coastal and near-reef waters. Their tooth shape is similar to modern sand tiger sharks and they are common throughout Cretaceous shallow-water fossil beds.
 

The presence of these species explains the abundance of fossilized shark teeth found in the creek today, often weathered smooth and darkened by time.

The paddle itself is intentionally short and accessible. Moving slowly upstream through the shaded creek, paddlers stop frequently to explore exposed gravel bars and shallow beds. Fossil hunting takes place directly in the creek, where participants gently pan and sift through sediment in search of shark teeth and other marine remnants.

This stretch of Post Oak Creek is especially productive. Seasonal flow continually exposes new material, and no two days reveal the same finds. It is common to uncover multiple shark teeth in a single outing, along with fossilized shell fragments and other marine traces.

No one goes home empty-handed.

Long after the inland sea vanished, Indigenous tribes lived and traveled along Post Oak Creek, drawn by its reliable water and sheltered environment. Later, settlers recognized the creek as a natural resource corridor, using it for grazing, water access, and transport through the region.

The towering shell beds would have been just as striking centuries ago as they are today, standing as visible evidence that the land itself held stories far older than human memory. Even now, the creek feels set apart from modern time, quiet, shaded, and slow.

This paddle is not about distance or speed. It is about observation, patience, and hands-on discovery. The shaded creek, cool air, and dramatic fossil walls create an environment where learning happens naturally.

Participants leave with fossils in hand, questions answered, and a deeper understanding of how dramatically this landscape has changed. Shark-Infested Waters is proof that North Texas was once an ocean floor, and that its most powerful residents still leave traces behind for those willing to look.

Some paddles take you forward.

This one takes you back.