Article XXVI. — THE FRESH-WATER TERTIARY OF 

 NORTHWESTERN TEXAS. AMERICAN MUSEUM 

 EXPEDITIONS OF 1899-1901. 



By J. W. GiDLEY. 

 Plates LII-LVIII. 



In the spring of 1899 Professor Henry F. Osborn sent an 

 expedition, under the leadership of the writer, to the Llano 

 Estacado or Staked Plains in northwestern Texas, for the 

 purpose of exploring the Miocene, Pliocene, and Pleistocene 

 beds previously reported from that region by Professor E. D. 

 Cope and Mr. W. F. Cummins, of the Texas Geological Survey, 

 This expedition met with such success that a second and third 

 expedition were sent to this region in the successive summers 

 of 1900 and 1 901. The results of the work of the three years 

 are comprised in this report. 



The following brief itinerary of the three expeditions seems 

 necessary to a clearer understanding of the region explored 

 and the relations of the different localities visited. 



Expedition of 1899. 



Clarendon, the county-seat of Donley County, a little town 

 on the Fort Worth and Denver City Railway, was the chief 

 base of outfitting and supplies, and the initial starting-point 

 of the three expeditions. 



The writer, with Mr. Alban Stewart as assistant and Mr. 

 Alfred Brown as cook and teamster, left Clarendon July i, 

 1899. . Going north about ten miles the first camp was estab- 

 lished on Barton Creek, where a thorough exploration of the 

 surrounding country was made. 



As reported by Cope and Cummins, the beds occupying the 

 tops of the divides in this vicinity are true Miocene and, 

 though of not great vertical thickness nor extensively exposed, 

 are very rich in fossil remains. Several good fossils were 

 found at this locality, the most important being a partial 

 skeleton, in a splendid state of preservation, of Mastodon 



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