METAM ORPHIC SERIES OE SHASTA COUNTY. 599 



dence that the European Carboniferous species found in America 

 migrated through the ocean that connected on the west the 

 American with the European Carboniferous waters. 



The Mc Cloud Limestone. 



Occurrence and character. Immediately above the Baird 

 shales, and probably conformably with them, lies the McCloud 

 limestone. This series is about 2,000 feet in thickness, uniform 

 in bedding, and very siliceous in places. Some few beds are 

 altered to a crystalline marble, but in the main the series is 

 made up of a fine-grained hard grey limestone, which at the 

 base contains few fossils besides corals, Clisiopliyllum gabbi, Meek, 

 and Lithostrotion californiense, Meek. But towards the top the 

 beds become more fossiliferous and contain a varied assemblage 

 of species, which however do not rival in number those of the 

 Baird shales. 



Trask 1 first visited this limestone at Bass' ranch near Still- 

 water, and recognized that it belonged to the Carboniferous 

 formation and probably the upper division. The Geological 

 Survey of California 2 afterwards visited the same locality and 

 collected a number of fossils, that were described by F. B. Meek 

 in Volume I. of the Paleontology of California. These were 

 thought by Meek to indicate a horizon below the Coal Measures, 

 although he leaves the question open, from the fact that many 

 species that in the Mississippi valley or in Europe would be 

 thought to indicate Subcarboniferous, in the West are found in 

 the Upper Carboniferous. 



The McCloud limestone is first seen at Bass' ranch near Still- 

 water, south of Pitt river. Where the Pitt river cuts through 

 the limestone disappears, being probably faulted out of sight, or 

 as Fairbanks 3 puts it, is "pinched out." But north of the Pitt, 

 and east of the McCloud, the limestone starts up again, forming 

 prominent mountains that rise 2,400 feet above the river. These 



'Report on the Geology of the Coast Mountains, 1855. 



2 Geology of California, Vol. I., pp. 326-7. 



3 Geology and Mineralogy of Shasta County, p. 35. 



