The Santa Monica Mountains

by Yevindra Boralessa

Evolution of the Mountains● In the beginning, broad plains extended from the middle

of California to the coast, while much of the Los Angeles area was underwater (National Park Service, n.d.)

● About 16 million years ago, volcanic eruptions caused the land to burst through the water’s surface

● For another 3 million years, the mountains continued to grow to over 10,000 feet high (National Park Service, n.d.)

● Today, the mountains include active fault lines, fossils, remnants of volcanoes, and even formations created underwater now at the top of ridgelines. (National Park Service, n.d.)

Lizard● Kingdom: Animalia, Phylum: Chordata, Superclass:

Tetrapoda, Class: Reptilia, Order: Squamata, Suborder: Lacertilia

● Terrestrial herpetofauna are reptiles and amphibians that occur primarily on land, and include species salamanders, lizards and snakes. (National Park Service, n.d.)

● Reptiles arose about 310-320 million years ago during the Carboniferous period, while the first lizards evolved in the late Permian period, more than 250 million years ago

Cactus● The evolution of the cactus has been one for debate as

there has been no actual fossil identified to date (cactus, n.d.)

● In 1944, Eopuntia douglasii was believed to be a fossil of the cactus found in Utah, but was later disproved after after much controversy and conflicting evidence was brought up (cactus, n.d.)

● The origin of the cacti has thought to be the Carribean Islands and north South America (cactus, n.d.)

● The cactus is an angiosperms, thought to have approximately 1,500-2,200 species and about 100 genera (Cactus, n.d.)

Horse● Horses are "perissodactyls” - hoofed mammals with

odd numbers of toes (Prehistoric, n.d.).● The ancestor of all modern horses was

Hyracotherium (Prehistoric, n.d.).● During the Miocene epoch, the grassy hills that

covered the North American plains drove the prehistoric horses to evolve to fill this niche (Prehistoric, n.d.).

● During the Miocene epoch, North America saw the evolution of "the horses called the Epihippus (Prehistoric, n.d.).

● The Epihippus was bigger, slightly heavier (possibly weighing a few hundred pounds) and equipped with more robust grinding teeth than their ancestors (Prehistoric, n.d.).

Shale● A fine-grained sedimentary rock made of mud that is

a mix of flakes of clay minerals and tiny fragments of other minerals (Wikipedia)

● Shale is formed by the process of compaction (Wikipedia)

● Typically deposited in very slow moving water and are often found in lakes and lagoonal deposits, in river deltas, on floodplains and offshore from beach sands. (Wikipedia)

o This is consistent with the location, which is close to the ocean, and used to be under water

Limestone● Limestone is a common sedimentary rock

composed mainly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (Wikipedia)

● Most limestone is composed of skeletal fragments of marine organisms such as coral or foraminifera, which can be explained by the mountains’ evolution as ocean converted to a mountain range (Wikipedia)

Oil Shale● Oil shale is a type of sedimentary rock that contains

significant amounts of organic material in the form of kerogen, which can make up to ⅓ of the rock (Wikipedia)

● Liquid and gaseous hydrocarbons can be extracted from the rock through heating or treating with solvents (Wikipedia)

● Formed by the deposition of organic matter in a variety of depositional environments including freshwater to highly saline lakes, epicontinental marine basins and subtidal shelves (Wikipedia)

o Santa Monica mountains fit into environment characteristics as a former marine environment

Chert● A type of microfibrous sedimentary rock that

sometimes contains small fossils (Wikipedia)● Chert varies in color, depending of elements

present in the rock (Wikipedia)

● Forms when microcrystals of silicon dioxide grow within soft sediments that will become limestone or chalk

● Dissolved silica is transported to the formation site by groundwater, which is consistent with the location of discovery, which used to be ocean

Gabbro● A type of igneous rock that is coarse-grained, dark

colored, and intrusive (Geology.com)

● Contains feldspar, augite and sometimes olivine (Geology.com)

● Formed as molten magma trapped beneath the Earth's surface slowly cools into a holocrystalline mass (Wikipedia)

● Consistent with the evolution of the Santa Monica mountains, created by volcanic eruptions

References● Prehistoric Horses - The Story of Their Evolution. (n.d.). Retrieved from

http://dinosaurs.about.com/od/otherprehistoriclife/a/horses.htm● Evolution of the Cactaceae. (n.d.). Retrieved from

http://www.labs.agilent.com/botany/cacti_etc/html/evolution.html● Wikipedia, the free encyclopedia. (n.d.). Retrieved August 3, 2014, from

http://en.wikipedia.org/wiki/Lizard#Lizard_diversification● lacnps.org - About the Santa Monica Mountains. (n.d.). Retrieved from

http://lasmmcnps.org/santamonicamtns.html● History & Culture - Santa Monica Mountains National Recreation Area (U.S. National

Park Service). (n.d.). Retrieved from http://www.nps.gov/samo/historyculture/index.htm● Geology.com: News and Information for Geology & Earth Science. (n.d.). Retrieved from

http://geology.com/