THE WAR DEPARTMENT, CORPS OF ENGINEERS UNDER THE COMMAND OF FIRST LIEUTENANT GEORGE M. WHEELER CONDUCTED GEOLOGICAL EXPLORATIONS AND SURVEYS IN 1871 THROUGH 1874 OF TERRITIORIES WEST OF THE 100TH MERIDIAN. THE 1871 EXPEDITION HAD TIMOTHY O'SULLIVAN AS THE PHOTOGRAPHER. O' SULLIVAN HAD BEEN THE PHOTOGRAPHER FOR THE CLARENCE KING EXPEDITONS NORTH OF THE 40TH PARALELL IN 1867 THROUGH 1869 AND HE RETURNED TO THAT REFINANCED EXPEDITON IN 1872. HE WAS REPLACED BY WILLIAM BELL AS PHOTOGRAPHER FOR THAT YEAR ON THE WHEELER EXPEDITION. O'SULLIVAN RETURNED TO THE WHEELER EXPEDITION IN 1873 AND 1874. IN 1875 AND 1876 THE WAR DEPARTMENT PRODUCED SETS OF 50 STEREO VIEWS OF THE FOUR YEARS. THESE CARDS HAVE BEEN ASSEMBLED FROM THOSE SETS. THERE ARE TWO VIEWS OF CARD NUMBER TWO FROM SEQUENTIAL NEGATIVES. APPARENTLY SOME SETS HAD ONE OF THE CARDS AND OTHER SETS ANOTHER CARD. VIEWS NUMBERS 31 AND 32 ARE PSEUDOSCOPIC. O'SULLIVAN WAS HIRED ON A CONTRACT BASIS TO PRINT VIEWS OF THE EXPEDITON. THESE VIEWS WERE PRINTED BY HIM OR UNDER HIS SUPERVIESION. CLICK ON A VIEW TO SEE THE ALBUM FOR THE YEARS NOTED. THERE WAS A 100 CARD SET FOR THE YEARS 1871, 1872 AND 1873. I HAVE ADDED A CARD FROM THAT SET FROM 1873.