Metamorph ic Rocks.— Fairbanks. 157 
morphism, that, aside from their stratigraphical relation it would 
be almost impossible to separate them from the Cretaceous. 
A series of statements which may seem to carry weight are 
summed up by Dr. Becker.* These are based on the occurrence 
of the fossil Aucella which at present seems to be considered 
indicative of the lower Cretaceous. It is distributed quite gen- 
erally through the shale and calcareous strata which are seldom 
metamorphosed to any degree. The occurrences mentioned by 
Mr. Becker as observed by himself and his assistants, and also 
by Mr. Gobb, are, as far as my observation has gone, invariably 
confined to what I consider, from a stratigraphical standpoint 
alone, as belonging to the Cretaceous, to say nothing of the 
lithological characters of the two formations; characters which 
are constant over great areas and widely distinct from each other, 
Besides this there is an abrupt transition from unaltered shale to 
the metamorphics. Prof. Whitney noticed this in many places 
4)n the theory of regional metamorphism, is it likely or even 
possible that such a sharply defined line could exist if both were 
concerned in the same upheaval and consequent metamorphism? 
It seems to me that we can come to no other conclusion but that 
the Cretaceous age assigned to the metamorphic rocks of the 
(oast Ranges is merely assumed and not proved. The finding of 
Aucella in the unaltered shales near the metamorphics is no proof 
of the Cretaceous age of the latter. 
My work in Shasta county developed the fact that in addition 
to the fossiliferous limestone of Carboniferous age first reported 
by Dr. Trask and those described lately by J. 8. Diller, there are 
several others rich in fossils. The most interesting discovery, 
however, was that of the existence of fossils in three different 
localities in the Auriferous series and on both sides of the lime- 
stone areas. These occur in slaty rocks conformable with the lime- 
stones and in part Carboniferous. No non-conformity between 
any of the metamorphic rocks was observed in the county, and | 
see no reason for doubting that the upheaval of all the meta- 
morphic rocks took place at the same time. At the time of this 
upheaval an extrusion of granite took place along the line be 
tween Trinity and Shasta counties, forming the Trinity mountains. 
That this granite is more recent than the Auriferous series is 
proved conclusively not only by the metamorphism induced in the 
*Bull. U. S. Geological Survey, No, xrx, p. 9. 
