The first edition of the "Directory of Geological Material in North America" was published in the Bulletin of The American Association of Petroleum Geologists, Volume 30, No. 8, Part II, pp. 1321-1432, August 1946, in a printing of 6,322 copies. An overrun of 1,817 copies was made to provide sale copies. In 1952, 542 copies were reprinted by photo-offset, and this supply was exhausted during the early part of 1955. The broadened coverage of the second edition made its publication by the American Geological Institute desirable, and accordingly its publication was transferred to the Institute by the Association.
The complexity of geological exploration, the diverse character of data upon which it is based, and the number of areas in which it is being carried on, have expanded greatly since 1946. As a consequence, many new sources of information have come into existence, some old ones no longer exist, and many addresses have changed. For these reasons, when the 1952 reprinting was exhausted, it was decided that a new, completely revised edition should be prepared and published as a special volume.
The second edition follows the general plan of the first, with a section listing sources of broad geographic and topical scope; and another section listing in detail sources of information available within each province or state, in which the data are of local application. Many sources of interest to geologists in mining and other branches of the science have been added. The second edition, like the first, could have been prepared only with the help of many collaborators, and the compilers extend their deep appreciation and gratitude to those whose names appear at the head of each geographic unit.
Although effort was made to produce a list of information sources more complete than that of the first edition, there no doubt are important omissions. Additions, corrections, and suggestions for more useful presentation of the data will be welcomed, and filed for use in future revisions.
Particular credit should be given to Robert H. Dott, and Mrs. Jane Weaver Wilds, who have attended to the many details involved in the revisions and additions.
J. V. HOWELL
A. I. LEVORSEN
May 15, 1957