RITA AE TED SLSR EN, RIE EL AE 
102 GEOLOGY. 
towards which we had directed our course. We therefore, on starting, turned more to the right, 
expecting to turn the point and find Carrizo creek and the emigrant trail. We were, however, 
disappointed, and then kept on towards the next point. We soon found a change in the color 
of the soil, and left the bluish and reddish clay, and found a low ridge, formed of the upraised 
edges of a sedimentary strata, consisting of sandstones and clays, outcropping with great regu- 
larity, and extending in a direction twenty-five degrees west of north for a long distance. 
These strata were mostly of fine clays of different colors, varying from grey to yellow, red, 
and pink. "They were very thinly and regularly stratified, and altogether showed a thickness 
of over two thousand feet. "These strata were filled with concretionary or nodular masses of all 
conceivable shapes and sizes. These were not only found in the sandy strata, but were also de- 
veloped in the argillaceous beds in great number and variety. 
CONCRETIONS, COLORADO DESERT. 
The figures represent some of the forms that were procured. These curious and singular 
masses were found lying in long parallel lines upon the surface, being derived from the out- 
cropping edges of the strata. One of the more sandy beds furnished great spherical nodules as 
large as ten-pin balls or bomb-shells. Some of the balls were connected together by & smaller 
sphere, which made them resemble dumb-bells. Other strata produced long, elliptical masses 
or cylinders, pointed at each end. The more clayey and finer sediments contained flattened 
ellipsoids, or kidney-shaped masses, and oblate spheroids of various colors, possessing a fine and 
smooth surface, which becomes polished by a little rubbing. 
CONCRETIONS LYING IN LINES ON THE SURFACE. 
Some of these masses were true septaria, and, when broken, exhibited numerous ramifying fis- 
sures, lined with crystals of carbonate of lime. Such was the variety of forms displayed on the 
surface, that it was not difficult to find specimens resembling various fruits and vegetables, fancy 
pastry, and confectionery. In nearly all of these strange and irregular forms the original planes 
of stratification were distinctly visible. 
The greater part of the edges of these inclined strata were worn down to the general level of 
the slope, and we travelled over them ; a portion, however, rose into a hill of slight elevation, 
and on its sides and top the calcareous incrustation was distinctly developed. Thus the Ancient 
lake registered its existence upon upraised Tertiary or Secondary strata, as well as upon the 
granite. We travelled nearly all day upon these strata, for the greater part of the time follow- 
ing the outcropping edges ; but towards evening the road became so rough, and the prospect of 
a passage for the wagons in the hills beyond was so slight, that we retraced our way for two OF 
three miles, and turned towards the north, crossing all the strata in succession. Their dip ۴۶ 
