Altadena Quadrangle: Supplement 1 from "A report on the geology of a portion of Los Angeles County located west of the city of Pasadena, California" (Thesis)

The area discussed in this report is located in Los Angeles County and lies partly within the city limits of Pasadena. The area extends from the Arroyo Seco on the east to a northsouth line about half a mile west of Eagle Rock, and from a eastwest line along the southern part of the San Rafael hills southward a distance of three to three and one half miles. The map used in the field work is a portion of the U.S.G.S. Altadena Quadrangle with scale 1/24000 and vertical contour interval five and twenty five feet. This map was found to be unusually accurate topographically. The purpose of this paper is to report the results of a general geological survey of the area outlined above. The usual brunton compass was used for field location. Locations are not indicated by numbers on the map as it was found more convenient in the field work to refer to specific points by their distances and directions from street intersections. The extreme northern portion of the area is covered with thick brush. All the other parts of the area are covered with grass or in the more hilly portions, with a light brush covering. The lowest point in the area (located in the south central part) has an elevation of approximately 550 feet while the highest point (located in the extreme northwestern portion) has an elevation of approximately 1,400 feet, giving a total relief of 850 feet