564 REPORT OF NATIONAL MUSEUM, 1893. 



quarried stone must be dragged on wagons over this 50 miles of roadway 

 to riioeuix, and tlience sliipped by rail. With tliis great drawback, 

 coupled with high freight imposed by a railroad free from competition, 

 tlie <]uarries labor under great disadvantage, 



Tlie country rock here is a slaty schist injected with quartz porphyries 

 and diorites, all sporadically overlaid by basalt, the diorite cropping 

 out in the rounded foothills, and weathering reddish. The main onyx 

 letlge lies on the western slope of alow basalt-capped hill. The lowest 

 underlying rock, as exposed in the creek bed a few rods below the 

 quarry, is also basalt, but of a coarse texture and gray color. In the 

 quarry opening the lowest rock exposed is a calcareous breccia, formed 

 of fragments of slate and pebbles of basic eruptive rocks cemented by 

 i\ friable travertine. At the time of the writer's visit (August, 1S92) the 

 ©ntcrop, as exposed by digging, was some 200 yards in length and pre- 

 sented some remarkable features. The maximum thickness of the bed 

 was about 10 feet. As exposed, it was not, however, continuous, but 

 evidently had been thrown out of place and more or less shattered and 

 broken by the extrusion of the basalt, the face of the quarry having 

 the appearance shown in pi. 10. 



The prevailing colors here, as at Mayers Station, are green and yel- 

 lowish, with veins of ocherous brown and red. The tints are beautiful 

 in the extreme, and the best quality of the stone is certainly very tine. 

 Clear uniformly green stone is not to be had in blocks of any size, but 

 all are filled with reticulating veins. There is a large amount of waste 

 material in the stone thus far removed, owing to the oxidation which 

 has gone on in the same manner as at Big Bug Creek. There are also 

 occasional small masses of chalcedonic quartz. The deposit is unique, 

 in that the largest blocks thus far obtained have their greatest dimen- 

 sions at right angles with the plane of deposition. Slabs 4 feet wide 

 could thus be cut across the grain, and while by this method the beau- 

 tiful blending of the colors is lost, still the wood-like grain, or onyx-like 

 banding, is thus brought out, and is greatly preferred by some. At date 

 of writing nearly all the material thus far quarried has been literally 

 dug out of the tufaceous material, in the form of corroded, irregular 

 blocks of all shapes, and in sizes including at most but a few cubic feet 

 What the large bed will yield, and how far it extends into the hill, is 

 yet to be ascertained. (See pi 11.) 



California. — Within the State limits of California are several deposits 

 of onyx marble, which may, with the increasing wealth of the country, 

 become important sources of supply. At present but one is actively 

 worked, difficulty of access and cost of transportation, together with 

 a limited market on the Pacific Coast, operating against an extensive 

 development. The most noted of these deposits, and indeed the only 

 one that has yet proven of any commercial importance, is located near 

 the town of Musick, San Luis Obispo County, in the heart of the Santa 

 Lucia Mountains. According to the report of the State mineralogist* 



* Tenth Arm. Rep. State Mineralogist of California, 1890, p. 584-85. 



