Todilto Formation

It preserves fossils dating back to the Callovian stage of the middle Jurassic period.

[1][2] Based on varve counts in the Luciano Mesa Member, the formation was laid down in a geologically brief period of time,[3] likely in a salina (a coastal body of saline water) that was replenished both by rivers and by seepage or periodic flooding from the Sundance Sea.

[4] The presence of dasyclad algae in the Luciano Mesa Member indicates at least some marine flooding.

[6] The formation is mined for gypsum in the northern Albuquerque Basin, including along the La Bajada escarpment south of I-25, near San Felipe Pueblo, and at White Mesa near San Ysidro.

Gregory in 1917 for exposures at Todilto Park in the San Juan Basin.

Luciano Mesa Member near Abiquiu, New Mexico