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dZ CONTRm UT10N8 TO ECONOMIC OEOLOOY
<br />uftner, and Hara~ajor in 1948; G. Ii. Wood, Jr., R. B. Johnson,
<br />td G. H. Dixon, nsslsted by I{. W. Brett, in 1949; G. H. Wood, Jr.,
<br />~. B. Johnson, and G. Ii. Dixol, assisted by J. D. Hill, in 1950; R. I..
<br />(arbour wilt G. II. Dixon, rand R. B. Johnson with J. G. Stephens,
<br />t 1951; It. L. I{arbour assisted by R. L. Iioogle in 1952; and R. II.
<br />oltnsott assisted by J. E. Doty in 1956.
<br />Fieldwork consisted of mapping sedimentary formations, coal beds,
<br />teats nud metamorphic rocks, rand structural features on single-lens
<br />hotogrnphs. Individual beds of sandstone were traced laterally
<br />+here exposed to facilitate correlation of coal beds. Coal beds were
<br />nensured, described, rand correlated iu the field wherever outcrops
<br />vere available for exuminnt.iou. The base for the small-scale regional
<br />eologic map (pl. 12) wns prepared from plnnimetric quadrangle
<br />naps compiled in 1940 by the U.S. Folest Service.
<br />Vortical control for structure contouring wns obtained over most
<br />f the coal field photogrammetrically, or with a telescopic alidnde
<br />rom bench marks previously established by the Coast and Geodetic
<br />tmti•ey rand the Geological Survey. In the southeastern quarter of
<br />ie Spanish Peaks quadrangle vertical control tt•ns taken from recent
<br />opogrnphic maps by the U.S. Geological Survey. The drainage,
<br />ulture, rand geology were transferred from aerial photographs to
<br />ase maps by use of stereoscopic plotters or vertical projectors.
<br />The nutbor wishes to express appreciation to Dlr. J. H. P. Fiske of
<br />be engineering firm of Douglas, Corey, and Fiske in Walsenburg,
<br />bolo., who kindly supplied much information consisting of mine maps,
<br />liamond-drill records, rand the descriptions of coal seams.
<br />PREVIOIIS WOR%
<br />Con] ltns been known in this general Wren for almost n century rand
<br />ltnlf, nttd ninny reports !rave !teen written on the geology, paleon-
<br />ology, and con] resources of the Trinidad field. Geologic features
<br />vere described by American exploration parties before the region was
<br />cquired by the United States in 1845. The expedition of Dfnjor S. H.
<br />,Drag to the Rocky 11lountnins in 1819 rand 1820 repotted coal near
<br />7nnon City, Colo. (.Tames, 1821; Long, 1823). D4ilitnry expeditions
<br />>.y Abelt (1848) rand 1stnory (1848) discovered coal in the Trinidad
<br />oral leld in 1846, rand Abert collected fossil plants near Trinidad
<br />which Bailey (1848) determined to be "younger than Carboniferous".
<br />Territorial surveys under the leadership of I'. V. Ifnyden visited
<br />to cool field, described the rocks, rand referred the cool-bearing rocks
<br />o the Tertiary (Hayden, ]BG7, 1868x, 18686, 1873, 187Gu, 18766, rand
<br />877). Lo Conte (1868) in n survey for the Union Pacific Railway
<br />txnmined fossil plants and shells near Triuidnd, Colo., rand concluded
<br />RE60URCE5 OF TICiNIDAD COAL FIELD, COLORADO L:i.i
<br />.that the coal ryas of "middle Cretaceous" age. In n report~ tines
<br />and mining trot of the Rocky Dfountnins, Raymond (1870) d~ribed
<br />coral beds rat several localities in the Rntat D1esn region.
<br />Lesquereux (1871,1872n,18726, 1873,1874n,18746,1874c,1878,and
<br />1883) described specimens of fossil plants from near Trinidad, along
<br />the Purgatoire River, nltd several other localities, nttd regarded these
<br />plants as being Eocene in age. However, Newberry (1874) took issue
<br />with the views of Hayden and Lesquereux, rand stated that the conl-
<br />bearing beds aro of Cretaceous rage. In a description of the Raton
<br />coal field of Nety Dfeaico, St. Jolttt (1876) agreed with Hayden and
<br />Lesquereua tltnt the coal beds rare of Tertiary age. Endliclt (1877)
<br />tnnde the first detailed study of the Trinidad coal field in 1875, and
<br />concluded that the coal should not be assigned to either the Cretaceous
<br />or Tertiary, but should form a transition between them (Endlich,
<br />1877, p. 211). Stevenson (1879, 1881, 1885, and 1889), during the
<br />field seasons of 1878 and 1879, made a tllorouglt eauminat.ion of tlto
<br />coal field south of the Spanish Peaks, nttd Riggs (1887) Inter reported
<br />natural coke along the Purgatoire River.
<br />About this time, Hills begun ]tis studies of the Trinidad coal field,
<br />rand wrote n detailed article on the field in his report on the coral fields
<br />of Colorado (Hills, 1893). This article a•ns followed by his excellent
<br />folios describing the geology of the Elmoro (Hills, 1899), l\'nlsettburg
<br />{Hills, 1900), rand Spattisll Peaks (Hills, 1901) qundr•nngles.
<br />Lt 1889 Lakes begun his series of reports (1889, 1891, 1899, 1902,
<br />1903x, 19036, 1904n, 19046, 1905n, 19056, 1905c, 1905d, 1905e, and
<br />1911) on the fuel resources of the region nttd on the various coal
<br />mines and districts of the Trinidad cool field. Papers by Dlend
<br />(1900), Hosea (1904n,19046, rand 1905), Pluntb (1905), rand Whiteside
<br />(1909) described several cool mines nud mining districts in the field.
<br />Lee (1909), while studying the Raton cool field in Nevv Dfexico, di-
<br />vided the cool-bearing rocks into the Vermejo formation of Lnte Cre-
<br />taceous rage rand t.lte Raton formation of Eocene rage. IIe divided the
<br />formations nt the base of a prominent conglomerate which he defined
<br />as the basal Led of the Rn[on formntiou, rand which he interpreted
<br />ns reflecting nn unconformity between the Cretaceous and Tertiary
<br />systems. In ]rater papers (1911x,19116,1914, rand 1916) Lee vigor-
<br />ously supported the existence of nu unconfa•mity between the Ver-
<br />mejo rand Raton formations. His extensive work in the Triuidnd rand
<br />Raton coal fields cnlminnted in n comprehensive repa•t on the Raton
<br />Dfesn region (Lee, 1917). Lee collected the fossils that were described
<br />rand identified by I{non•Iton (1913, 1917).
<br />Richardson (1910) presented n detailed account of the cool
<br />resources of the Triuidnd coal field, rand continued to refer the conl-
<br />608808 O-Ill-2
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