Preliminary Digital Geologic Map of the Santa Ana 30' x 60' Quadrangle, Southern California

Geologic and geophysical maps of the El Casco 7.5′ quadrangle, Riverside County, southern California, with accompanying geologic-map database

“…To the south in the Badlands, the upper member is known to conformably overlie the middle member of the San Timoteo formation (Morton, 1978, although he did not map individual members of the formation; Morton and Matti, 2001b); here, the boundary interval wraps around the nose of the gently northwestplunging San Timoteo Anticline (Morton and Miller, 2006). As interpreted by earlier workers (English, 1953;Shuler, 1953;Matti and Morton, 1975;Morton, 1978b,c;others, 1992, 2003a,b;Albright, , 1999Morton, 1999;Matti and others, 2003a,b;Morton and Miller, 2006), strata north of San Timoteo Canyon are structurally and stratigraphically continuous with the San Timoteo succession where it wraps around the anticline nose in the Sunnymead quadrangle-even though San Timoteo Canyon intervenes between the two successions and its incision has obliterated evidence for a direct stratigraphic connection between them.…”

“…These materials previously have been mapped as "older alluvium" (Burnham and Dutcher, 1960, p. 64-66) or as the upper member of the San Timoteo formation (Morton, 1978b(Morton, , 1999others, 1992a,b, 2003a,b;Albright, , 1999Morton and Miller, 2006; many unpublished consulting reports). The unit is named for Live Oak Canyon in the Yucaipa 7.5′ quadrangle, where the formation is exposed in roadcuts and in low hills flanking the canyon.…”

“…Hammer head marks base of texturally massive to faintly laminated, feldspar-rich (arkosic) and lithic sandy rock underlain by gray to greenish-gray texturally massive mudrock and very fine sandstone. Morton, 1999). Very pale-brown conglomeratic sandy rock and sandy conglomerate (behind hammer) abruptly overlies chippy weathering mudrock and sandy mudrock; note texturally massive fabric of coarse rock and mottled aspect of mudrock.…”

“…Note absence of conglomeratic rock. Morton, 1999). Greenish-gray intervals are mudrock, white to very pale-brown intervals are fine sandy rock.…”

“…Until a type section is designated and described, map unit is classified informally. Subdivided into lower, middle, and upper members (Matti and Morton, 1975;Morton, 1999), with only lower and middle members occurring in El Casco quadrangle: QTstm Middle member (Pliocene)-Forms middle part of San Timoteo formation of Frick (1921). Unit consists of four principal lithotypes that recur throughout sequence: (1) thick sheetlike layers of conglomeratic rock; (2) light-gray to white sandstone and slightly conglomeratic sandstone; (3) reddish mudstone and sandstone; and (4) locally significant but minor grayish-green mudrock.…”