352 The American Geologist. J^ne, 1904 
ling the amphibolite schist of the Sierra Nevada region. Schis- 
tosity has been superimposed on the bedding structure of the 
Bragdon formation, but without totally destroying the latter. 
The coarse sandstones are still macroscopically apparent as 
such, but the grains have been flattened as in a squeezed con- 
glomerate. Usually the planes of schistosity and the bedding 
planes are practically parallel so that the formation still retains 
one of its great chraacteristics, that of regular and straight 
lamination. 
A line drawn almost due north-south through a point about 
two miles cast of Orleans on the Klamath river and a point 
about an equal distance east of Hawkins' Bar on the Trinity 
river will separate the territory in which this intense meta- 
morphism lias occurred from one on the east in which the 
same formations are very much less altered. No cause can yet 
be assigned for the limitation of the dynamical action. It seems 
to date from a time succeeding the Jurassic sedimentation, but 
antedating the early Cretaceous peridotyte intrusions, and it 
was probably connected with the great post-Jurassic folding 
of the region. 
At Orleans, in HumbokU county, there is a Bragdon area 
traversed bv the Klamath river for several miles. It trends 
north-south. A belt four or five miles wide properly belongs 
to this formation, but it is interrupted by serpentine and anoth- 
er igneous massif. Where the eastern border was observed at 
the Ten Eyck mine above the mouth of Salmon river, there is a 
narrow belt of sheared tuffs which is succeeded by the cherty 
limestone-bearing Paleozoic rocks. The schistose slate of the 
Bragdon formation preserves its thin-bedded shale and heavy- 
bedded coarse sandstone structure. Both types are splendidly 
exposed at Orleans where an Indian, Red Neck, ferries travel- 
ers across the river. The formation here has a regular wester- 
ly dip. This Orleans area continues southerly through the 
mountains for many miles and may connect with the main 
western area in the vicinity of Hoopa valley. 
In traveling up the Klamath river, another Bragdon area 
was encountered at the mouth of Slate creek, nearly midway 
between Weitchpcc and Orleans. It has the same lithologic 
characters as the others and is bordered on one side by the al- 
tered tuffs, but the other boundary is probably a fault. It is 
