Throughout most of California the lowly acorn was the main staple of life for the Maidu Produced in vast quantities by oak trees, acorns were harvested in the fall and carried in baskets to the village and dried. When they were ready to be used, they were cracked open and the nut meats ground to flour.
The Maidu used hand crafted pestles to grind acorn into meal creating mortars in the local bedrock.
Bedrock geology:
The rocks now present are part of the lofty Sierra Nevada, originating from molten material-magma-buried miles below the Earth's surface. Cooling and crystallization of this deep-seated magma required millions of years. The resulting rock, composed of interlocking crystals of several kinds of minerals, is called a plutonic rock, named for Pluto, the Roman god of the underworld. Formation of the plutonic rocks of the Sierra occurred over a long timespan, as magma episodically rose from the Earth's interior, intruding older host rocks, and eventually crystallizing to create one of many individual bodies of rock called plutons. Many of these plutons are today exposed at the Earth's surface due to erosion of the once overlying older rocks.
The plutonic rocks of the valley and adjacent uplands are composed of a variety of minerals. Five of these minerals make up most of each rock variety; quartz, two varieties of feldspar (potassium feldspar and plagioclase), biotite, and hornblende. If feldspars are potassium-rich (orthoclase) the granites may be tan to reddish in color. If feldspars are calcium-rich (plagioclase) light to dark gray colored. These minerals mainly comprise the elements silicon and oxygen, and all except quartz include aluminum as well. Other constituents of the feldspar include potassium, sodium, and calcium; biotite and homblende also include magnesium and iron.
These older rocks-slate, quartzite, marble, and metavolcanic rocks-formed by alteration, or metamorphism, from their original state-shale, sandstone, limestone, and volcanic rocks-with intense heat and pressure. The metamorphism both preceded and accompanied the intrusion of the plutons.
To log this cache, answer the following questions…
1. How many in your group?
2. How many Mortars (grinding holes) are there?
3. Estimate how long and wide the grinding rock is.
4. Based on your reading and what you see at the site, is the rock orthoclase or plagioclase?
5. How big is the fenced area around the rock?
6. (optional) Post a pic of yourself in the area. Not with the rock please.
Please send these answers to me in an E-Mail. Do Not post them in you log even if they are encrypted.
Please log your visit at the same time as you send your answers. If there are problems, I will contact you.
Found it logs without an E-Mail will be deleted without notice.
