—Prof Edward Hitchcock, 1828
All 50 of the American states have agencies that deal with their rocks, soil, water, and mineral wealth; lots of these are called "geological survey." It's a name with a long history, dating from the young days of the American nation when the states were few and the territory of the country was largely unknown.
The first geological surveys were just that—one-time efforts to map the state's rocks, especially the public lands, so the state could give away its lands and collect taxes on the most valuable resources. The first state Geological Survey was established in 1830, in Massachusetts, thanks to the vigorous efforts of Prof. Hitchcock, quoted above. Tennessee started one the next year, and quickly thereafter most of the states funded surveys of their lands.
The idea of a geological survey was not new, but it wasn't sexy until the 1820s. Before then, the USA's major earth resources were considered to be timber, agriculture, coal, and base metals—iron, lead, copper. But what made the states prick up their ears was the discovery, up and down the southern Appalachian Mountains, of gold. (Long before California's Forty-Niners, the first American gold rushes were in the eastern states.)
The benefits of the surveys being so great—and governments being what they are—most of these one-shot surveys turned into permanent agencies. The federal government got into the act in 1879, and the United States Geological Survey eventually became the world's premier earth-science agency.
So, did Hitchcock's vision come to pass? Well, the states all publish geologic maps and pamphlets, for free or very cheaply. But they aren't doing so well on the Web. When I set out to find geologic maps for all 50 states, I found only about half of them online—and of these only 15 were posted by state geologic agencies. Six years later, not much has changed.
When it comes to posting these maps, the simplest approach is just to scan the printed map and hang it as a GIF or JPG file. Georgia went the farthest with a gigantic life-size GIF, without a key. This is fine if you already know how to read a geologic map.
A more Web-friendly (and citizen-friendly) approach is to mount a clickable map that gives you close-ups or explanations of the different rock formations. Kentucky's, because it's based on a simplified geologic map, works fast and is good enough for the needs of most users. That one is from the Kentucky Geological Survey. (I feature a detailed image from the printed map.) The one for Minnesota furnishes specialized maps of bedrock, glacial deposits (which cover much of the state's bedrock), and various geophysical features, but it took the state university to do that.
The best maps I've found are collected in an A-to-Z list, the first and still the only place on the Web where you can access every state. I keep looking for official state maps to add to the list (and if you know of any, send me the URL!). But because the states are so slow, I got hold of printed maps and scanned them myself, adding a few notes about the state. It's the least I can do.
PS: If you would like your state to do more, write to the state geologist (find them all here) and bug him or her to put something on the Web. I want Prof. Hitchcock to rest easy in his grave. Oddly enough, the one geological survey he helped found—in Massachusetts—is the only one for which there was no state map online in any form, until I created one myself.
