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70 MEMOIRS OF THE CARNEGIE MUSEUM 
Tue History or tHe Discovery or tHe AGATE Spring Fosstn QUARRIES, 
WHERE THE SKELETON or Dinonyus Hotianpt was Founp. 
While engaged in field work for the Carnegie Museum on the upper Niobrara 
River, locally known as Running Water, Sioux County, Nebraska, in 1904, the 
writer had often been invited by Mr. James H. Cook to visit his ranch, the Agate 
Spring Stock Farm, located on that stream, some twenty-five or thirty miles east of 
the Nebraska-Wyoming state line. One day in the latter part of July, I decided to 
break camp and go down the river in search of new localities for fossils and also to 
study the geological features of the neighborhood more fully. As Mr. Cook’s ranch 
was on our way down the stream, it was decided to pay him a visit, and accord- 
ingly we stopped at his ranch. After a camp-ground had been pointed out to me, 
Fic. 23. Ranch-House of Mr. James H. Cook, Agate Spring Stock Farm. (From a photograph 
by Mr. Albert Thomson. ) 
on top of a high butte immediately to the south of the farm buildings, and arrange- 
ments for wood, water, ete., had been made, the preliminary work of prospecting 
the neighborhood was at once under way. A day or two later Mr. Harold Cook, 
the eldest son of Mr. James H. Cook, accompanied the writer to a small elevation 
some four miles to the east of the farm buildings and immediately beyond the east- 
