142 APPENDIX D. GEOLOGY. 



"The coal formation at the Brazos is found in a coarse, dark sandstone 

 rock, which is a solid stratum, but is easily removed in consequence of 

 being so soft. In excavating for a well, we passed through the sand- 

 stone and the coal. The greater part of the stone was removed with the 

 mattock ; and in the coal, which was here about sixty feet below the 

 surface, we found fossil ferns, which, unfortunately, were not preserved." 



The ease with which this sandstone was removed, requiring only a 

 mattock, corresponds better with the hardness of tertiary than of carbo- 

 niferous rocks ; yet, in some parts of the world, distant from igneous 

 rocks, the sedimentary strata are but little indurated. 



Your statement respecting the coal on the Brazos, and the import- 

 ance of the substance to the future inhabitants of the western side of 

 the Mississippi valley, led me to recur to the journals of other explorers, 

 as well as your own from Fort Smith to Santa Fe, published by the 

 government in 1850, to ascertain whether this valuable mineral does 

 not occur in such places as to justify the inference that a large coal 

 field may exist in that portion of our country. I have not all of the 

 necessary works of reference at hand ; but, in such as I have, I have 

 found the following cases, including those already described : 



1. Fort Belknap, on the Brazos river, latitude 33^° to 33f-°, longi- 

 tude 98° to 99°. 



2. Between Forts Washita and Smith, latitude 34° to 35^°, longitude 

 94£° to 96f °. 



3. On Coal creek, near the South Fork of the Canadian, eighty-eight 

 miles from Fort Smith, in longitude 96^°, latitude 34f°. "Bituminous 

 coal, used by the blacksmiths of the country, who pronounce it of an 

 excellent quality." (See Captain Marcy's report, p. 173.) 



4. North branch of Platte river, latitude 42° to 43°, longitude 104° , 

 to 107°; described by Rev. Samuel Parker, Exploring Tour, p. 73. 

 He calls this coal " anthracite, the same, to all appearances, as he had 

 seen in the coal basins of Pennsylvania." 



5. On the same route, Colonel Fremont found coal and fossil plants in 

 latitude 41-J- , and longitude 111 . The fossils greatly resembled those 

 of the true coal measures. He also found what was probably brown or 

 tertiary coal, in longitude 107°. 



6. Major Emory met with " bituminous coal in abundance," in lati- 

 tude 41°, longitude 105°. He was told of a bed thirty feet thick. 



7. Lieutenant J. H. Simpson describes bituminous coal in beds from 

 two to three feet thick, in latitude 36° 12', and longitude 108° 52'; 

 and he states it to be "coextensive with the country between the valley 



