202 The American Geologist. March, 1894 
Geo. F. Becker. Bulletin of the Geological Society of America, vol. ii, 
pp. 49-74, witli thirteen figures in the text; Jan. 10, 1891. This society 
within the first month after its recent meeting in Washington has 
published two of the communications received at that meeting, and it is 
expected that the others will follow in rapid succession. Mr. Becker in 
this important paper announces his discovery that the uplifting of the 
Sierra Nevada has been effected by many thousands of faults, varying 
in amount from a small fraction of an inch to three inches or rarely two 
or three feet, often well marked by slickensides and by measurable dis- 
placement on nearly vertical joint planes or fissures. Granite and 
diorite, overlain in part by andesite and basalt, form, the area studied, 
which has a length of about 80 miles and width of 30 miles, immediately 
west of the eastern scarp of the range. The fissure systems and the- 
faulting are referred to the period of andesitic eruptions, which the 
author here regards as Pliocene. But as he shows that the glaciation 
of the Sierra Nevada was very recent, and in another paper maintains 
the authenticity of the many reported occurrences of stone mortars and 
other implements and of human bones in the deep placer gravels, lava- 
capped, on the western slopes of this great mountain range, which 
belong to the date of beginning of this period of disturbance, faulting, 
and uplift, it seems more consistent to regard all these events as com- 
prised within the Quaternary era, the uplift of the Sierra being proba- 
bly contemporaneous with the first Glacial epoch. In all the faults- 
observed it is found that northerly walls have moved upward and west- 
ward relatively to southerly walls, and that easterly walls have moved 
upward and southward relatively to westerly walls. The theory that 
the earth is a solid, highly viscous mass appears to the author to be in 
all respects compatible with his observations, fully explaining the fissure 
systems, the faults, and the enormous resistance to tilting which the 
range has displayed. 
Tlie Phosphide Deposits of the island of Navassa. By Edward- 
D'Ixvilliers. Bulletin, G. S. A., vol. ii, pp. 75-84; Jan. 27, 1801. This 
island, lying between Hayti and Jamaica, is 2K miles long and IX miles 
wide, rising to a liight of 255 feet. It is of recent geologic age, and is 
formed of coralline limestone that has undergone elevation. Phosphate 
earths and rock, which are evidently leached guano deposits, fill 
irregular cavities and fissures in the surface of the limestone to the depth 
of about twenty feet. The gray phosphate, found on the lower flat or 
terrace, 10 to 70 feet above the sea, contains 65 to 70 per cent, of lime 
phosphate: and the red variety, found on the flat top of the island, 
contains 50 to 65 per cent. The yield of the gray phosphate is 1,500 to 
2,000 tons per acre, and the area originally occupied by it was about 244 
acres, more than half of which has been exhausted during the past 
thirty years of mining ; but only about a seventh part of the upper 300 
acres of red phosphate has been worked, leaving probably 300,000 tons 
of this variety. 
