Map of Orleans and St. Bernard Parishes Showing Lake Shore Developments & Etc. (detail top image) some time ago, and recently came across contemporary photographs of the Edgelake Subdivision in an advertising brochure.
The Southeastern Architectural Archive's Guy Seghers Office Records contain significant documentation of the Edgelake land holdings, as the Seghers family platted many of the associated neighborhoods. The developers chose reef shell for the subdivision's primary roads, including its park entrance (second image) and Curran Boulevard (bottom image). The Gulf Crushing Company, Inc. of New Orleans supplied the oyster shells. During the 1920s, Louisiana's road builders had difficulty forming and maintaining roadways using local clay-sand. It often failed to bond with gravel. The Old Spanish Trail was particularly susceptible to such road failures, and much of it had to be resurfaced with reef shell.
The shell was less expensive, and could also be used in emergencies to provide a safe path on flooded roadbeds. The shells required no binding agent, were durable, water resistant and provided traction.
Map: Wm. E. Boesch, Map of Orleans & St. Bernard Parishes Showing Lake Shore Developments & Etc. Copyrighted November 1926 by Wm. E. Boesch. Guy Seghers Office Records, Southeastern Architectural Archive, Special Collections Division, Tulane University Libraries.
Photographs from: Shell Roads in Louisiana. New Orleans: Gulf Crushing Company, 1927. Louisiana Research Collection, Special Collections Division, Tulane University Libraries.