Geological Survey Professional Paper Volume 420, PT. 1

Geological Survey Professional Paper Volume 420, PT. 1

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. Excerpt: ...Verdes Hills, silty, sandy, and siliceous shale with minor amounts of schist breccia and tuff are exposed (Woodring and others, 1946). In the Santa Ana Mountains the lower sequence consists of sandstone, pebbly sandstone, conglomerate, Figukk 9.--Distribution of middle Miocene rocks ln the Los Angeles basin. Location and number of each composite stratigraphic column are the same as ln plates 1,2, and 3. interbedded micaceous siltstone, and minor amounts of tuff and limy siltstone. In the southeastern foothills (near long 11737' W.), basal beds locally contain Catalina Schist detritus. In the central part of the nearby San Joaquin Hills, the lower sequence has been further divided into three named members (pls. 1 and 2). The lower member is conglomeratic sandstone and grit, the middle is dark-gray siltstone and interbedded sandstone that contains detritus of Catalina Schist, and the upper is tuffaceous siltstone and sandstone that contains interbedded andesite flows and sedimentary breccias of andesite. In the southwest San Joaquin Hills a few exposures of siliceous shale and siltstone contain Catalina Schist detritus. In the eastern Santa Monica Mountains the base of the lower sequence is an unconformity, which locally cuts down to Paleocene strata. In the Santa Ana Mountains and San Joaquin Hills the sequence generally grades down into marine strata of early Miocene age, but in the north part of the Santa Ana Mountains it rests on nonmarine strata. Farther southeast (south and east of long ll737i/2' W.; lat 3337y2' N.), the base is unconformable on marine lower Miocene strata. In most of the basin the top of the lower sequence is an unconformity, except in the Palos Verdes Hills and part of the San Joaquin Hills, where it grades into the more

Product details

  • Paperback | 40 pages
  • 189 x 246 x 2mm | 91g
  • United States
  • English
  • black & white illustrations
  • 1236974697
  • 9781236974693