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only its lower measures, or about half its actual thickness, which proba- 

 bly reaches 1,000 feet in this district. Looking northward, the same 

 formation and conformation prevail, and out of which seem to rise the 

 Spanish Peaks, the Purgatory intervening, but hidden in its valley 

 2,000 feet below. To the east, the view is arrested in the foreground 

 by the wild intricacy of ravines scoring the Tertiary deposits, above 

 which rears the massive wall of basalt which stretches far to the east and 

 southeast, constituting a blank horizon from its initial extremity in the 

 embattled heights of Fisher's Peak, which frown down upon the valley 

 of the Purgatory. 



This great table-land, the Chicorica Mesa, attains an elevation quite 

 equal to the general altitude of the Eaton Hills. The somber outlier 

 known as Fisher's Peak may even exceed this altitude ; but it plainly 

 sinks away to the southeast and east, and beyond the Trinchera it is no 

 more than 7,000 feet above the sea. Its sides in the southern declivity 

 are gashed by deep ravines, with intervening grassy, terrace-like slopes, 

 underlaid by the Tertiary deposits and strewn with the rough angular 

 fragments fallen from the dark basaltic wall above, which is rarely 

 broken down sufficient to allow easy access to its herbage-clothed sum- 

 mit. It is impossible to examine this great basaltic-capped mesa without 

 being forcibly impressed with the probable important influence it has 

 exerted not only in the origin but preservation of the Raton divide and 

 the Tertiary plateau. 



Thus, it will be seen that the Raton Hills in their entire extent are 

 composed of the great Lignitic formation, which abuts upon the meta- 

 morphic deposits which flank the main range, probably concealing them 

 from view at the point of impingement in the vicinity of the Francisco 

 Pass. It is along the crest of this divide that these Tertiary deposits also 

 probably maintain their greatest development, and where they may reach 

 a thickness considerably in excess of that just attributed to the forma- 

 tion. When the great escarpment-exposure is examined from the plains' 

 at a distance sufficient to afford a comprehensive view of several miles 

 extent, there is observed a marked diminution in the relative vertical 

 in extent of the formation in its extension southward, which, however, 

 does not appear to be a thinning in that direction of the sediments com- 

 posing its distinct strata, but rather the absence of successive superin- 

 cumbent beds which have been removed by denudation. This phenom- 

 enon is perhaps nowhere more markedly apparent than in comparing 

 the relative elevations of the buttressed heights, which mark the embou- 

 chures, like headlands along the coast, of the Canadian, Yermejo, and 

 the Cimarron ; and, to obviate the possibility of misconception, the eye 

 can trace the continuity of certain marked horizons in this magnificent 

 outcrop a distance of thirty miles. 



The diiierence in the relative level of the base of the formation at the 

 respective exposures. on the Cimarron and the Purgatory would appear to 

 indicate a gentle northeasterly inclination of the strata along the line of 

 this outcrop, amounting perhaps to 700 feet between the above points, 

 or in a distance of about fifty miles. But to the unassisted vision there 

 is no perceptible dip, while the apparent inclination is probably due to 

 the line of outcrop extending obliquely to the descent of the strata from 

 the flanks of the uiouutaius to the west, and possibly also in part attrib- 

 utable to the gentle uplift parallel with the Urac Mountain along the 

 southern borders of the coal-field. It would appear most probable that 

 these deposits have also participated to a greater or less extent in the 

 uplift along the western borders of the field, though it is hardly more 

 certainly apparent than the northerly inclination above alluded to until 



