Part of the Rowland's gift was donated to the Bancroft Library at UC Berkeley, and was described by Donald Thomas Clark as follows:
Spanish-American Files: 5 Wooden Boxes containing approximately 8,160 cards (3” x 5”) alphabetically arranged by names of Spanish-Mexican families – the first families of California and also other persons with Spanish-Mexican names that were in California 1769-85.
Ranchos: One half drawer containing approximately 935 cards (3” x 5”) containing information relating to Spanish and Mexican land grants and Ranchos.
The Bancroft Library cataloged this collection as follows:
This Collection is stored off-site at the Northern Regional Library Facility. An advance request via UC Berkeley’s Bancroft Library is required for its use.
The material in the Bancroft Library’s collections was used as the basis for Rowland’s Los Fundadores ... (published in Fresno, California, by the Academy of California Church History, 1951. Publication no. 3.)
Its subtitle reflects the content of this forty-six page compilation:
“Herein are listed the first families of California and also all other persons with family names that were in California 1769-1785 except those who died at San Diego in 1769.”
Rowland explained his intent, in the Foreword to Los Fundadores:
[it] presents an attempt to list the names of the men who came from Mexico to northern California in the first fifteen years of its settlement, most of them to remain. Soldados, pobladores, sirvientes and presidiarios compose the list. The mission priests are not included; a complete list of them will be found in the index volume to [Zephyrin] Engelhardt’s Missions and Missionaries.
Note: Los Fundadores was republished in Santa Cruz, The Early Years: The collected historical writings of Leon Rowland. (Santa Cruz, Paper Vision Press, 1980.)