The term marble was actually first used to describe a crazy "marble" type pattern on the dorsal area, and the speckling of the sides was also inherent in these animals. The marble pattern is kinda hard to describe tho, my girl kinda has it in the middle and then her tail and neck are normal. Sort of like there is no line seperating the speckling and dorsal, and lots of rich shading in the dorsal pattern. Since there have been alot of animals with just a normal dorsal pattern and speckling sides. It seems to me that the speckling is a dominant mutation while the marble pattern on the back is co-dom? or something (I know very little morph inheritance). Thus having two different morphs actually going on. IMO opinion animals that just have the speckling should be called something else like granite and what are being reffered to as true marbles as just marbles. This of course is just me blabbering.. hopefully someone who is more informed will chime in.
J
Hmm.. I have better pics but dont have permission to use them. This is a somewhat recent imported animal that has what appears to be a marbled pattern but not much speckling on the sides.

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"It's my snake, I trained it, so I'm going to eat it!" - Mad Max, The Road Warrior