>Many dutch ovens have a lip on the lid.<
Technically, Pete, all
Dutch ovens have recessed lids. What we refer to, today, as a Dutch oven is actually a lidded, flat-bottomed kettle.
A true Dutch oven has three legs and a recessed lid. In use, hot coals are swept under it, and additional coals laid in the lid. This creates the same surrounded-by-dry-heat environment as found in an oven, thus letting you bake in one.
Dutch ovens, as with all legged cookware, is designed to be used on the hearth, rather than in the firebox itself.
With the advent of "portable" cast iron stoves, ca 1820, neither the legs nor the recessed lid was needed anymore. So they were mostly replaced by flat- and round-bottomed kettles with domed lids, that could fit on, or in, the hob.
For camp cooking, a Dutch oven is the most versatile piece of cookware you can carry. Virtually any cooking technique, from baking to deep fat frying, can be accomplished in one.
I've got an article about Dutch oven cookery at my website. If anyone's interested, here's the link: Dutch Ovens Cooking. Cooking in the great outdoors.