Clayton Ahumada

Geology 1

Where My Samples Come

From… My samples come from different parts of California. I went to the

Central Coast near Paso Robles, Coalinga, Sonora, and Shaver Lake. The place I went on the central coast is a ranch on Cypress Mountain

Drive. It is west of Paso Robles, in the coastal range. My sample came from a stream bed. According to a geologic map of California that I found, the rocks in this area are from the late Mesozoic time.

The place I went to near Coalinga was on Highway 198, west of the town. I found this sample on the side of the road where they had cut away part of the hill to widen the road. You could see where pieces were falling from the hillside onto the road. The rocks in this area are from the Cenozoic time, I think.

The place I went to in Sonora, is my Grandpa’s house. He lives right outside of town, near a stream. I found this sample in his garden. The rocks in this area are from the Mesozoic time, I think.

Two of my samples are from Shaver Lake, California. I got them at the Boy Scout Camp there last summer. Both were taken from exposed areas near the water. The rocks in this area are from the Mesozoic time, I think.

This is the site I used to decide how old the rock were in the places I went to. http://geology.about.com/library/bl/maps/n_statemap_CA1000.htm

Example #1This rock sample was found at Shaver Lake. It has a course texture

and is light colored. Having seen Granite before, I knew this was

Granite. Granite is intrusive and you can clearly see the grains. A

rock-hound friend, suggested I show the rocks dry and wet, so you

could see the difference.

Example #2This sample was found in the coastal range, west of Paso Robles. It has

a fine texture, it’s a dark reddish brown color. It has definite cracks, so I’d

say non-uniform cleavage. It looks like it has fine bands of quarts in it

(white lines) with some crystals. I’m not sure what this is. I asked my

rock-hound friend and he said it was Jasper. When I looked in our rock

and mineral identification book, however, it didn’t look like Jasper to me.

It didn’t look like any of the samples in the book.

Example #3

This sample was found on Hwy 198, west of Coalinga. It has grains

that you can see, but they aren’t course. They’re more like sand. It

has definite cleavage. It was breaking off of the hillside and falling

onto the road. It has a grayish color with bands of red and brown. It

looks to me like Sandstone.

Example #4I got this sample at my Grandpa’s in Sonora. This is the stuff he pulls out

of his garden all the time. It has a fine texture, and reddish, orange color.

It looks like what the rock and mineral books says is Jasper.

Example #5

I found this sample at Shaver Lake as well. It was in a different spot ,

called Eagle Point. It has a glassy texture. It is white to almost clear in

color. It has definite crystallization. I think it is quarts.