The Hazel mine is one of the oldest mines in Texas and has been the largest copper-producing property in the State. The mine has a recorded production of over 1 million pounds of copper and over � million ounces of silver, and there are a number of years in which the mine was active but for which no figures are available. True production is in the neighborhood of 4 to 5 million ounces of silver and 1� million pounds of copper. The Hazel mine is the most important of a group of mines and prospects known as the Allamoore�Van Horn copper district.

The Ellenburger of Texas was first defined as a marine limestone formation of Cambrian and Ordovician age (Paige, 1912), but recently it has been subdivided into several formations and the term Ellenburger given group status (Cloud and Barnes, 1948). The group forms an important unit in the geology of Texas, its known extent in both surface and subsurface covering approximately one-half of the State (fig. 1). Consequently the Ellenburger has received the attention of many geologists over a period of more than forty years.

Cain City quadrangle is south of the Llano region and is in the marginal portion of the Edwards Plateau where much of the plateau surface has been destroyed by erosion. Northeastward-trending lobes and outliers of the Edwards Plateau are present in the southern part. The rest of the quadrangle is in the gently undulating broad Pedernales River basin.