Sept. 8, 1870] 
NATURE 
385 
The Cirro-stratus, but more especially the Cirro-cumulus, are 
remarkable by reason of a characteristic of the highest impor- 
tance, from the point of view of the distribution of congealed 
aqueous yapour, and one which has escaped the sagacity of 
Howard and his successors. It consists in the most fantastical 
combinations, reproducing all the formations, hydrological, and 
physical, of our Continent and seas. Here a deep bay with pro- 
montories, capes, peninsulas, isthmuses, &c. ; there, a river, 
brooks, lakes, &c.! further on, vast continents and open seas. 
The entire mass and the outlines of each of these accidents are 
besprinkled with Cirro-cumudus, sometimes edged with Cirro- 
stratus, of which the yolumes of little balls are seen diminishing 
and yanishing from centre to circumference, while at the side, in 
the empty spaces, we perceive the purest azure of the heayens. 
Should it be a lake, the water will be represented by the blue 
sky, and zerra firma by the Cirro-cumudus which surrounds it. 
By carefully studying all these transformations we remark in 
~.them the greatest analogy with the phenomena of the precipita- 
tion and congelation of dew upon solid bodies. There is, there- 
fore, at this altitude, in the same stratum, and one after the 
, other, so to say, some portions of the atmosphere enjoying dif- 
ferent degrees of density and of temperature, in order that the 
congelation of aqueous vapour may take place in so variable a 
manner, 
The influence of Cirro-cumudius upon the lowering of the tem- 
perature at the surface of the earth is so considerable that the 
human body feels it at once. A curdled sky at the new moon 
of a calm night in the tropics is a sky relatively glacial for these 
latitudes, 
This effect may be due to their greater proximity and to the 
considerable quantity of balls of snow which constitute this type 
of cloud. The Cirrus being found much elevated and the Crrro- 
stratus much less abundant, although both are formed of glacial 
aiglets, have not the same influence upon the terrestrial tempera- 
ture. Howard says: 
“The Cirro-cumudus is formed from a Cirrus, or from a number 
of small separate Cirrus, by the fibres collapsing, as it were, and 
passing into small, roundish masses, in which the texture of the 
Cirrus is no longer discernible ; although they still retain some- 
what of their relative arrangement. ‘This change takes place 
throughout the whole mass at once, or progressively from one 
extremity to the other. In either case the same effect is pro- 
duced on a number of adjacent Ciyrus at the same time and in 
the same order. It appears insome instances to be accelerated 
by the approach of other clouds. 
**This modification forms a very beautiful sky, sometimes ex- 
hibiting numerous distinct beds of these small connected clouds, 
floating at different altitudes. 
“The Cirro-cumulus is frequently seen in summer, and is 
attendant on warm and dry weather. It is also occasionally 
and more sparingly seen in the intervals of showers and in 
winter. It may either evaporate or pass to the Czrrus or Cirro- 
stratus,” 
Under the generic name of Pad/iwm, I have classed two forms 
of clouds, which present the appearance of a mantle or veil 
of considerable extent, of very compact texture, well defined at 
the edges, of an excessively slow march, and embracing, 
moreover, the visible vault of the sky. According as the 
FPallium is formed of Cirrus or of Cumulus it is distinguished 
into Pallio-cirrus and Pallio-cumulus. The appearance of these 
clouds signalises bad weather, and their disappearance good 
weather. 
The stratum of Pa/lio-cirrus is first formed, and some hours 
or some days afterwards that of Pallio-cumudlus is formed under 
it. These two strata remain in view at a certain distance from 
each other, and by their reciprocal action and reaction produce 
storms and the heavier rains, accompanied with considerable 
_ electric discharges. They are electrified, but with contrary signs ; 
the superior stratum of Cirrus is negative, and the inferior one 
of Cumulus is positive, the same as the rain which it disengages ; 
while the electricity of the air, at the surface of the earth, is 
negative. But when these two strata attract each other a dis- 
charge is produced ; and the inferior stratum continues to pour 
out the surplus water it contained without giving any sign of 
electricity, no more than the air in contact with the earth. ‘This 
state continues until the inferior stratum opens up, the superior 
afterward, they then disappear, the one after the other. Fine 
weather then returns. The Pad/ium chiefly predominate during 
the rainy season, in inter-tropical regions, and in the higher lati- 
tudes during winter, at the time of fallsof snow. A part of the 
Pallio-cumulus, which has not been reduced, or which has not 
been scattered to other regions, gathers at the horizon and is 
transferred into the Cumulus. As to the Pallio-cirrus, they 
disappear entirely if fine weather is maintained. 
THE ANCIENT LAKES OF WESTERN AME- 
RICA, THEIR DEPOSITS AND DRAINAGE * 
HE wonderful collections of fossil plants and animals, 
brought by Dr. Hayden from the country bordering the 
Upper Missouri, are from deposits made in extensive fresh-water 
lakes which at one time occupied much of the region lying 
immediately east of the Rocky Mountains, The water of these 
lakes was first salt or brackish, as the remains of oysters and 
similar estuary forms show. By continental elevation the 
whole country west of the Mississippi was raised out of tle 
cretaceous sea, and these estuarics became lakes inclosed by 
raised dry land. The knowledge of this country from the 
Mississippi to the Pacific Ocean has been accumulated by variovs 
explorers besides the writer, as Dr. Hayden, Mr. George Gibbs, 
Professors WW. P. Blake and Thomas Antisell, and Prof. J. D. 
Whitney and the State Geological Survey of California, and 
Baron Richtofen, the lamented Rémond, Drs. Shiel, Wislizenus, 
and others. Besides Mr. Clarence King has explored a large 
tract of this country, but his very important contributions have 
not, as yet, been made public. The general character of the 
topography of the region west of the Mississippi has been given 
by these great lines of elevation traversing the county from 
north to south. There are the Rocky Mountains, the Sierra 
Nevada, and the Coast Ranges. The last is the most modern, 
and is composed, for the most part, of Miocene Tertiary rocks, 
Parallel with this lies a narrow trough, in California traversed 
by the Sacramento and San Joachin Rivers, encroached on by 
the mountains at places, but still in Oregon and Washington, 
traversed by the Willamette and Cowletz Rivers. These two 
sections are drained through the Golden Gate and Columbia, 
The mountain barriers formerly caused the valleys to consist of 
great inland lakes, which are now only represented by the chain 
of small pieces of water still to be seen inthat region of country. 
East of the Sierra Nevada and between it and the Rocky 
Mountains is another still larger basin. For a thousand miles it 
has no openings to the westward, which are less than five thou- 
sand feet above the sea, but at three points there are gateways, 
which may be passed, but little above the sea level. These are 
the canons of the Sacramento (Pit River), the Klamath, and 
the Columbia. These have been cut through by the drainage of 
the interior of the continent. The former beds of the lakes 
have thus been left dry and waste—the only real desert on the 
North American continent. ‘The Sierra Nevada is older than 
the Coast Ranges, and projected above the ocean, though not 
to its present altitude, previous to the Tertiary and even Creta- 
ceous ages. ‘This we learn from the fact that strata belonging 
to these formations cover its base. The mass of the Sierra 
Nevada is granitic rocks and metamorphic slates, proved 
by the California Survey to be triassic and jurassic. These 
slates are traversed by the gold-bearing quartz. East o: 
the Sierra Nevada is a high and broad plateau five hundred 
miles wide, and from four to eight hundred feet in altitude, 
and reaches south into Mexico. This mountain belt was once 
the margin of the Pacific Ocean. Its crest is crowned by vol- 
canic cones like gigantic towers of a fortification. The central 
portion of this plateau was called by Fremont ‘‘ the great basin,” 
as it forms a hydrographic basin drained by the Columbia and 
Colorado, The former makes its way to the ocean through a 
gorge in the Cascade Mountains, whilst the latter escapes to the 
south through a series of caons, of which the most important 
is nearly a thousand miles in length, and from three to six 
thousand feet deep. In vol. vi. of the Pacific Railroad Reports 
the country of the Columbia is described and the reasons for con- 
cluding that it had cut its way through the Cascade Mountains, 
and similar facts were observed in the district drained by the 
Kamath aud Pit Rivers. Certain peculiarities are to be seen in 
the country between the Sierra Nevada and Rocky Mountains. 
In the northern and middle portions of the great table lands the 
surface is somewhat thickly set by short and isolated mountain 
ranges, sometimes called ‘‘the lost mountains.” These rise 
like islands above the level of the plain, and are generally com- 
* Contributed by Professor J. S. Newberry to the Proceedings of the 
New York Lyceum of Natural History. 
