26 GEOLOGY, 
the summits in broad, white fields that glistened under the rays of an unclouded sun, and by 
its rapid melting kept the rivers well supplied with water. 
The crest of the chain, nearly east from the ferry, has a very peculiar appearance, and seems 
to be divided into a succession of tranverse ridges, standing sharply out at right angles to the 
general direction of the chain, giving it an outline like the teeth of a saw. 
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CREST OF THE SIERRA NEVADA, FROM KING's RIVER. 
Three principal ridges of this character were easily seen by the naked eye, but with a glass 
many more were observed. They were evidently the outcropping edges of rocks dipping to- 
wards the south at angles of seventy to eighty degrees. Their outlines were deeply serrated ; 
and this appeared to be the result of the breaking or gapping out-of their sharp edges, either 
by abrasion, or, more probably, by the undermining action of the weather, permitting por- 
tions of the rocks to fall by their own weight. The nearly level spaces between these singular - 
ridges were covered with snow, but no snow could be observed on the abrupt and precipitous 
slopes of the rocks. It is possible that the valleys are occupied by glaciers. 
The distinctness with which these serrated rocks are visible at the distance of probably over 
fifty miles, and at an elevation of over seven or eight thousand feet, shows that they have @ 
great elevation above the general surface of the ridge. A similar structure is developed along 
the crest of the chain for several miles towards the south. I was surprised to find such an ex- 
tended series of outcrops with their trend apparently at right angles to the general direction of 
the chain on which they occur. From the character of their edges and the tabular appearance 
of their surfaces, I concluded that they were slate rocks— probably metamorphic or azoic. 
From King's river to the Four Creeks the surface of the ground shows but few undulations, 
and may be considered as nearly level. The soil contains a large portion of clay, and must 
necessarily become soft and miry during the rainy season. About three miles northward of 
Elbow creek, (one of the ** Four Creeks,") a large area of surface is composed almost wholly of 
clay, without any admixture of sand or gravel, and has evidently been nearly fluid in the wet 
season. "This was shown by the deep tracks of animals in the then hard, sun-baked surface, 
and by great numbers of skeletons of cattle that have sunk in the deep, thick mud, and been 
left to die of starvation. Their whitened bones stand upright in the clay like posts around a 
grave. The drying up of this clayey ground has produced deep shrinkage cracks and fissures, 
similar to those observed in the rich soils around the bay of San Francisco. 
Four Creeks.—From the level of the arid and treeless plain, bounded on the west in the dim 
distance by equally barren mountains, we made a sudden descent of about ten feet to the bot- 
