Metamorph te Rocks.—Fuirbanks. 159) 
Near the Cold Fork of the Cottonwood and about two miles from 
the metamorphics, the first specimen of Aucella was observed. 
The strata here dip nearly vertical and are greatly broken. The 
rocks against which they rest consist of quartzites, crystalline 
limestone with poorly preserved fossils, thin cleavable shales 
highly metamorphosed, green talcose schists changing to contorted 
and silicified green schists on Tom’s Head and westward to the 
North Yallo Bally where they are gnarled and knotted in the 
highest degree. 
On Elder creek the Aucella is found in abundance together 
with other lower Cretaceous species, but the contact with the 
metamorphic series is not to be observed on account of a great 
mass of serpentine. Mr. J. 8. Diller, who has investigated this 
region carefully, has proved that both divisions of the Shasta 
group are represented on Elder creek; the lower, the Knoxville, 
having a thickness of nineteen thousand nine hundred feet, while 
the upper or Horsetown is represented by six thousand one hun- 
dred feet of shale and sandstone. These two beds were demon- 
strated to be continuous from top to bottom without physical 
break.* This accords with the latest views of Dr. Becker, who 
found a commingling of the faunas of these two divisions at 
Riddles, Oregon.t Mr. Becker had previously announced that 
the great upheaval of the Coast Ranges took place at the close of 
the Knoxville.t The conformity shown to exist between the two 
divisions of the Shasta group is in perfect accord with my own 
observations. -A very important fact results from these conclu- 
sions; since the Horsetown and Knoxville beds are conformable, 
and the upper, or Horsetown, rests unconformably on the meta- 
morphic series in Shasta county, a fact acknowledged by all ob- 
servers, then the lower or Knoxville, when present, must also 
rest unconformably on the metamorphic series, if it can be proved 
that these metamorphics are continuous with those of Shasta 
county. After a most careful tracing of the older rocks of 
Shasta county southward, I find it utterly impossible to draw a 
line of demarkation between themand the metamorphics of either 
Tehama, Colusa, Lake or Napa counties. There is no physical 
break. 
*Bull. Geological Society of America, Vol. Ie p. 207. 
+Bull. Geological Society of America, Vol. II, p. 203. 
{Geology of the Quicksilver Deposits, p. 460. 
