Preliminary notes. Report No. 1a(1), USSBS Index Section 2

Preliminary report. Report No. 60h(1), USSBS Index Section 2

Preliminary report. Report No. 90a(1), USSBS Index Section 2

Notes and work sheets: Preliminary report-draft. Report No. 93a(1)(b), USSBS Index Section 2

Preliminary report-draft. Report No. 90b(1), USSBS Index Section 2

Preliminary report-draft. Report No. 91d(1), USSBS Index Section 2

Preliminary report-draft. Report No. 92p(1), USSBS Index Section 2

Preliminary report-draft. Report No. 95c(1), USSBS Index Section 2

Preliminary report-draft. Report No. 92e(1), USSBS Index Section 2

Preliminary reports. Report No. 95e(1), USSBS Index Section 2

Reports, notes, and work sheets: Preliminary analysis. Report No. 92f(1)(h), USSBS Index Section 2

Preliminary report-draft. Report No. 93g(2), USSBS Index Section 2

Preliminary report-draft. Report No. 93h(2), USSBS Index Section 2

Preliminary report-draft. Report No. 93b(2), USSBS Index Section 2

Preliminary report-draft. Report No. 93e(2), USSBS Index Section 2

Preliminary report(draft). Report No. 60h(2), USSBS Index Section 2

Preliminary report-draft. Report No. 93d(2), USSBS Index Section 2

Preliminary report-draft. Report No. 93f(2), USSBS Index Section 2

Preliminary draft of final report. Report No. 40a(1), USSBS Index Section 2

Miscellaneous correspondence. Report No. 1a(16), USSBS Index Section 2

Miscellaneous photographs. Report No. 1a(17), USSBS Index Section 2

Preliminary draft. Report No. 93c(2), USSBS Index Section 2

Preliminary drafts Report No. 43a, USSBS Index Section 2

Preliminary draft. Report No. 2a, USSBS Index Section 2

Notes and preliminary drafts of related material. Report No. 39ff(10), USSBS Index Section 2