Iron in the United States, exclusive of Alaska and Hawaii

The iron-ore deposits in the United States (exclusive of Alaska and Hawaii) are shown on the accompanying map; many iron-bearing deposits that are of lesser or only potential value are also shown. Because these deposits range widely in extent, two general categories of symbols are used, each of which is subdivided as explained below. The first category is for deposits of such restricted extent that they can be represented by a "spot": the second is for deposits which, although not necessarily extremely large in terms of volume or tonnage, are either continuous (or essentially so) or clustered in reasonably well-defined districts of numerous small occurrences.