Calif ornian Metaniorphic Formations. — Hcrshey. 231' 
often repeated three or four times in parallel lines within sev- 
eral miles transverse to the strike of the slates, apparently as 
the result of folds or faults. Some of these "lime dikes" have 
a width of several hundred feet and stand out boldly above the 
surrounding- slates. The limestone is usually massive and 
crystalline in character. Generally the metamorphism has 
proceeded to such an extent as to have completely destroyed the 
fossils, but near the Sacramento and McQoud rivers this is not 
the case, and there the limestones furnish the material for the 
determination of the age of this series. 
The areas of the Lower Shale series are characterized : — 
1. By the peculiar outcrop of the quartzyte ; the surface of the 
hills abounds in fragments of cherty quartz either stained to 
light tints of red, yellow or brown or having a whitish, bleached 
appearance. It is difficult to convey anaccurate impression of 
what is here meant, but it is a feature universally present in 
all the areas of this series no matter how widely separated or 
whether representing its upper or lower members. No other 
formation outcrops in quite the same way although internally 
it may resemble this. 
2. By abundant dikes of greenstone intruded into the 
series and cutting across the stratification. 
3. By the belts of limestone. Limestone and marble occur 
in the earlier, schists but are insignificant in development in 
comparison with those of the Lower Slate series. 
4. By a certain degree of dynamo-metamorphism which 
is comparatively uniform throughout the series and is of the 
nature of regional and not local or contact metamorphism. 
The formation is commonly contorted, faulted and sheared 
throughout. Much of the argillaceous material has been con- 
verted into hornblende and micaceous minerals, but this is not 
macroscopically prominent. The sandstones have been partial- 
ly recrystallized and thoroughly lithified. The limestone has 
usually been altered to a distinct crystalline aggregate pre- 
senting little evidence of its original condition. The general 
appearance of the series is one of practically the same age 
throughout, and as a whole much older than the Mesozoic 
slates, to be described later, and much newer than the schist 
series, discussed in preceding pages. 
In Trinity county, the Lower Slate series is chiefly devel- 
