Planning a family vacation means accommodating everyone’s interests, so I’m usually allowed one day to spend doing an astronomical roadtrip. Why should this year be any different? The destination was my parents’ house, and the sideshow was 94 miles to the east: Serpent Mound, Adams County, Ohio. Let me explain.

I worked as a part-time janitor at the Cincinnati Natural History Museum while in high school. Part of my duties there included trail maintenance at the museum’s nature reserves in Adams County. Southern Ohio is particularly well known for its many Native American mounds and village sites. I had once participated in an archaeological dig near home, in fact, that was how I got the museum job. So you would have thought that I had visited Serpent Mound, an effigy earthwork in the form of a snake, but I never did for some reason. Imagine my surprise when I found Serpent Mound on a list of recognized impact crater sites. This was a place I had to visit at long last!

There are many mysteries surrounding Serpent Mound. Who built it, when and why just for starters. The effort that went into its construction is considerable: the body is two to six feet high and twenty feet wide. Stretched out, it would extend over a quarter mile in length. The outline uncoils from a tail to a meandering body and a triangular head. The snake appears to be eating an egg or frog, or in a more astronomical interpretation, the Sun in eclipse. Maybe the effigy represents a comet or even the constellation we know as Draco. Adding to the mystery is the fact that snake’s head or egg, er, frog points precisely towards sunset on the summer solstice. This certainly supports some sort of celestial interpretation to the site.

The enigma deepens when it comes to the impact site. Serpent Mound is on a narrow promontory above Ohio Brush Creek, built on the edge of a ring grabben. There is no crater per se, but an area of disturbed, faulted, uplifted and down-dropped blocks of rocks four miles in diameter. Technically known as a cryptoexplosion structure, something really big happened there about 200 million years ago. Erosion has taken away much of then evidence since then, but the structure persists in the jumble of differently aged Paleozoic rocks, younger on the rim, older in the central uplift. The surface trees and vegetation give away the underground structure: the different rock strata lend the soils acidic and alkaline properties. Geologists don’t all agree that a meteor impact occurred, and some suggest that a mile-deep underground explosion is responsible. It’s not clear that the mound builders in any way recognized the anomalous geology, or that they constructed earthworks at any of the other seventeen cryptoexplosion structures in the Midwest. Just a coincidence at Serpent Mound? Perhaps...

Besides these academic inquires, there is renewed popular interest in Serpent Mound. It’s a New Age power center, a harmonic convergence of astrological powers. It is also the U-Haul pictorial "supergraphic" for Ohio trucks. You can explore much more of this for yourself on the web: for example, try a google.com search on “Serpent Mound.” Some web sites are a bewildering compendium of the Native American, geological and astrological significance of this ancient earthwork amongst the farms in Adams County.

So as interesting and mysterious as this all was to me, the others were ready to head back to their grandparent’s house. We stopped to stretch our legs halfway on the two-hour ride back. The kids especially enjoyed the decidedly non-astronomical activity of fossil collecting at a highway road cut. Yep, that was also another of my former hobbies. Maybe I can work that into next summer’s vacation...

One of the things Doug found in his parents’ house was a box of his old photographic prints and negatives--including some early astrophotos. Look for those in a future installment. Moondark is written by Doug Miller, published on the web, and printed in the Delmarva Star Gazers' Star Gazer News. Please address comments and suggestions to dcmiller@dmv.com. This document was last revised on 26 August 2001. All text and images copyright © 2001 Douglas C. Miller, All Rights Reserved. This material may not be reproduced in any form without prior permission.