Derek Thompson and Joseph W. Wiedel and associates. AN ECONOMIC AND SOCIAL ATLAS OF MARYLAND. University of Maryland, Occasional Papers in Geography, Number 3, Department of Geography, College Park, Maryland, 1974. 126 pages, paper cover. $5.00. Peter Gould and Rodney White. MENTAL MAPS. Penguin Books Ltd., Baltimore, Maryland 1974. 204 pages, paper, $2.95.