120 REVIEWS. 
* With the nommenpentent of the rinm v wae ushered in the dawn of ta eront lake period 
of the Tek " f the tertiary 
period, e up to the commencement of the present, there was a continuous series of fresh- 
Water lakes. e pret the continent west of the Mississippi River. Assuming the position that 
, progressive, and long-continued, and that the earlier sedi- 
ments of the tectiney, were marine, then brackish, eec purely. fresh waten, we Wiame: reum 
a of e gro y step, 
p to the d time. The earliest of pr fecit lakes marked the commencem ment of the 
tertiary period, me seps - have ee nivel a ven large — aai the American continent 
west of he A f Dar 
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whie Lr we sg lave called the White River tertiary basin. We believe din it commenced its 
growth near has south-eastern base of se. Disk agisce and gradually enlarged its borders. I 
1 ost or quite up pi ihe QUERN 
ot the present period; t tl d l he 
Upper Arkansas, in the Middle Park, among the mountains at the ‘source of the Missouri 
River, in Texas and California, and Utah, are all later portions of this great lake. The upper 
i in the Win ve 
mi r e deposit. ver Valley, near F ,and on the divide 
between the Platte and the Arkansas Rivers, were undoubtedly synchronous, though perhaps 
not eonnected 1 this great very year, as the limi ar 
nded any direction, I fi es of what — to be separa e basins, 
greater o , and bearing insic proof, m less pipet dig of the time of their 
existence. I hav 9 gen in this pia e the above b Pelis; to of the various geologi 
formai sas Ll lied tl West, in digi that my subsequent remarks on these 
formations in their southern extension may be more clearly understood. Constant reference 
will be medo to pus as the ey have aique seen in the e E h and West, in order that the story 
of thei y be linked together 
Dr. Hayden also speaks of having met with vast quantities of true drift 
material which he regards as originating from the neighboring mountains. 
i 
kinds, but slightly worn; but proceeding from the base of the mountains, 
the rocks become smaller and more rounded, until they pass into small 
pebbles, mingled with loose sand. 'The phenomena of erosion, as seen at 
the present time, all along the flanks of the mountains, in the plains, in 
the channels of streams, point clearly to a vastly greater quantity and 
force of water than exist anywhere at the present time." A page is de- 
nis bre familiarity with them enables him to condense into so 
brief as Bey 
“It is now well known ite: the great Rocky Mountain PENE BER is not composed of a single 
range, but a vast series of ranges, covering a width of sìx hundred a one thousand miles. 
Toore are also two kinds of ra iota wen "e a i granitoa nucleus, with long lines of fracture, 
the 
us, and is cor 
posed of a series of yotesuie cones or outburs of igneous rocks, in many cases forming thada 
saw-like rid or sierras, as the Sierra Nev - Sierra Madre, ete. Along the easter rtion 
of the Rocky Mountatns, os the north line to New Mexico, the ranges with a a grani toid nu- 
cleus prevail. Each one of tl a number of fragmen 
which — m des — from a definite direction, but the aggregate trend will he 
about and south-e: 
_ As I have | before stated, cach one of the main ranges seems to me to form a gigantic anti- 
and the lower parallel ranges a ng like steps to 
the plains, or to the m valley. If,for exam agp we were to aud pipund one a ne 
minor mountain ranges, as the Black Hills of Dakota. re the 
ey very complet e and er we should find a Souter: granitic axis, and. on — - AT scu 
p 55 5 y no: rth and so! And 
