saddle reef

Noun

 * 1) A mineral deposit associated with the crest of an anticlinal fold and following the bedding planes, usually found in vertical succession, especially the gold-bearing quartz veins of Australia.
 * 2) An opening at the crest of a sharp fold in sedimentary rocks, occupied by ore.
 * 3)  A saddle-shaped bedded mineral (usually gold-bearing quartz) vein occurring along the crest of an anticline or  a syncline (an inverted saddle).