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_ *  #° -- 
Having érossed the Arkansas, I met with the first rocks again, on the 
“middle springs of Cimarro n,” (468 miles ;) it~ was a sandy limestone 
above common sandstone. +» 
Six’ miles west of the Crossing of Cimarron (500 miles from Independ- 
ence,) light bluffs rise in the prairie, of a yellow, reddish, and s otted 
sandstone, combined with lime and argile. 
A few miles beyond them’a large, isolated mountain of boulders stands 
in the plains, composed of heavy blocks of quartz and ah sand-" 
stone, and mamy erratic rocks were afterwards found’ on our roa 
n Cedar creek, McNees’ creek, and Cottonwood branch, a yellow 
saitaatbine prevailed. rae 
On ina ear creek I met for the first time with amygdaloidal basalt, 
a black, heavy, basaltic rock, with a a great many irregular, vesicular cavi- 
et thatiar are generally hollow—sometimes, ee filled with lime ; ; in rare 
instances, with sae This rock is most common throughout the high 
mountains of M Tt occurs in init irregular masses, in whole - 
mountains, as wrall as in millions uf pieces strewn over the surface of the 
country. Here it rose in high perpendicular walls, as bluffs of the creek, © 
and a very compact quartzose sandstone was below in horizontal layer. 
The Round mound, a ntain in the prairie about three miles further 
west, which | precited ib aitiied of a brown, decontposed basaltic rock. 
On Rock creek, and Whetstone creek, the amygdaloidal basalt with un- 
pee sandstone was found. 
n going from there to “ Point of Rocks,” (600 miles,) extensive strata 
of a yellow, compact quartzose sandstone are passed, dipping gently to- 
wards the east. Point of Rocks — a dad of the western mountains, 
is a mass of sienite. . 
‘Some 12 miles beyond it, rises a hill in the. plains, composed of ‘very 
compact, black basalt, with "underlaying white sandsto 
The bed and bluffs of the Rio sheet ge and Ocaté Neral (627 miles,) 
are formed by quartzose sandston 
The Wagon mound, an ieutasst mountain in the om plain, consists of 
@ compact, black, and s spotted basalt, rising in colum shape. 
‘On Wolf creek = miles) the amygdatoidal on fa a sand- 
" stone reappeared, both in horizontal layers. 
Reaching the Gallinas creek, near las Vegas, (690 miles,) T met, after’ 
long interval, with limestone again. “It was a dark blue, with casts of 
Inoceramus of the cretaceous series. 
From here we penetrated into the very heatt of the mountains. A 
. first we met but with sandstone, common and quartzose, and of most aif 
” ferent col 
Near San San Miguel (707 miles,) a coarse eonglometate was foiina of Bex’ 
composed granite; sandstone, and lime, and large blocks of decomposed 
gtanite lined the Pecos river, opposite the old’ Pecos village, (737 miles.) 
In the caiion leading from here to Santa Fe , at first sandstone is found, | 
ommon, ‘quartzose, and calcareous, of various colors and granulations, til 
afloat 15 miles from Santa Fe, granite in sitw appears, and continues all 
the way to Santa Fe. Near where 1 met for the first hve with granitein 
sit, the sand po may judge from a very limited examination, was 
West of Santa Fé, granite seems also to prevail. In. my Sxeraenionel 
to the Placers, southwest of Santa Fe, I found sandstone below, and on. 
the height of the mountains granite and trap ro rocks. 
