This symposium was held at the Academy of Natural Sciences, to which 3500 people were invited. Of this group 441 are known to have been in attendance because they signed the register of visitors and delegates. Many of the records were kept by Virginia Tomlin and supervised by Edgar Howell and preserved in the Department of Geology. The collection includes a large scrapbook of news clippings, invitations, programs, a typescript of the advance program for March 17-20, 1937 and abstracts and texts of papers to be presented. Transcripts of the papers given at the various round tables are preserved in duplicate and concern three different chronologies, The card file of invitations is included and has some thousands of entries, the cards indicate the atldresses and the acceptance or regret of the person, university, society or editor invited.