Terra Cotta, California
Coal, along with clay deposits, was found on the site by John D. Huff in the late 1880s, and the Southern California Coal and Clay Company was formed to mine them. The town site of Terra Cotta was laid out and was given a post office on October 26, 1887. In May 1893 its post office was closed and moved to Lake Elsinore. A plant for the manufacture of sewer and water pipes was built using the coal to fire ceramic pipes in the four kilns. The finished product had to be shipped by wagon six miles through Lake Elsinore to the La Laguna rail station at the mouth of Railroad Canyon until 1896 when a spur line was built through Lake Elsinore and Terra Cotta to the new clay deposits in Alberhill. The coal mined was also used locally as fuel for the stamping mill at the Good Hope Mine and was shipped elsewhere in the state.
Parc Slate Quarry
Moses Kellow, who was born on 5 June 1862 at Delabole, Cornwall, close to one of the largest slate quarries in Britain. His parents moved to Caernarfon some three years later, and besides his school education, his father trained him in engineering and geology. By the age of 20, around 1882, he was managing Parc Quarry. Slate in the Blaenau Ffestiniog region is generally found in veins which slope downwards at an acute angle from the horizontal, resulting in the quarries being underground once the initial surface rock has been removed. The veins are separated by layers of harder rock, often granite or chert, which are called "hards". The slate vein worked at Parc Quarry was about thick, and sloped downwards at about 42 degrees. Unusually, the pillaring line, one of the planes in which rock can be split, was almost horizontal rather than vertical, and the foot joints did not run in a suitable direction to detach slate blocks from the floor of a chamber. Additionally, the rock above the vein was not hard enough to support the roof of large chambers. Because of this, Kellow's father, William, decided in 1880 to work the quarry from the bottom upwards, rather than adopting the more normal practice of working from the top downwards.