| 1. | 1837 - 1866 | Apprenticeship, engraver, service in Civil War -- Washington D.C. |
| 2. | 1866 - 1869 | Initial activity as professional artist -- New York and St. Paul |
| 3. | 1869 - 1870 | First trip west, with King's Geological Survey -- San Francisco |
| 4. | 1870 - 1872 | Interlude back east -- New York and St. Paul |
| 5. | 1872 - 1873 | Second trip west, under own sponsorship -- San Francisco |
| 6. | 1873 - 1877 | East coast artist & third California trip -- New York and St. Paul |
| 7. | 1877 - 1886 | Establishment in Europe -- London |
| 8. | 1886 - 1893 | Barbizon period -- Paris |
| 9. | 1893 - 1901 | Reestablishment in America -- Washington D.C. and New York |
| 10. | 1901 - 1903 | Health problems -- Washington D.C. |
| 11. | 1903 | Aftermath |
| 12. | Sources | References to sources cited in Archive |