Turtle Back Rock

Everybody do the Turtle Back Rock! Lift your glove and lift your sock!

If you’re ever bored at the Turtle Back Zoo [site], you may find yourself wondering why on earth they named the place Turtle Back Zoo. Did they used to ride on the backs of turtles? Is it an homage to some obscure turtle legends from the local Lenape indians?

No! None of this. None at all.

Right near the zoo, there’s a “bluff over Northfield Avenue that has extensive markings— grooved ovoid patterns that are textured like those on a turtle’s back, except larger (Sceurman and Moran 2005, 33).”

Hence: Turtle Back Rock, and subsequently… Turtle Back Zoo.

And these turtleoid rocks are all over the place! When I visited, I was expecting one big rock with turtle marks. Nope! Every boulder in a 20-foot radius looks like a turtle!

Another turtle back rock face!

A turtle back boulder!

The main turtle back hangout rock, I guess

While the guys from Weird NJ speculate as to the markings’ potentially otherworldly origins, Turtle Back Rock was formed by pretty mundane geology.

Apparently, when the local basalt lava cooled into basalt trap rock, it split into hexagonal crystals (“blocks”). Non-basalt minerals filled in the cracks, and erosion deteriorated the mineral fillings more quickly than the basalt rock. So the grooves in the “turtle’s back” indicate areas where minerals filled the gaps in basalt.

Cool, huh?



Lord Elwood and RakeInTheCache. (2007). Waymarking.com. “A turtle’s back rock formation.” http://www.waymarking.com/waymarks/WM2BPK_A_Turtles_Back_Rock_Formation.

Sceurman, M. and Moran, M. (2005). Weird N.J.: Your travel guide to New Jersey’s local legends and best kept secrets. Sterling Publishing Co., Inc.: New York. ISBN 1402766858.

7 Responses to “Turtle Back Rock”

  1. Neat! Does this type of rock formation exist elsewhere?

  2. This brings me back to my childhood. Haven’t thought about turtleback zoo in years. Never did know why it was called that until now. Thanks for the good memories!

  3. Correction: The guys from Weird NJ NEVER “speculated as to the markings’ potentially otherworldly origins.” That would just be plain stupid. – Mark M (one of the guys from Weird NJ)


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