120 W. Z. Dudley — Curious occurrence of Yivianite. 



SO, 12*60 



CaO 49-54 



Al a 3 15-45 



Fe 2 O s .. 0-91 



H a O(by diff.) -..- 21-40 



100-00 

 closely agreeing with the above composition. 



Chemical Laboratory, No. Ill S. 10th St., Philadelphia, April 6th, 1890. 



Art. XIY. — A Curious Occurrence of Yivianite ; by 

 Wm. L. Dudley. 



While making the preliminary survey of the Cumberland 

 river from Nashville to its mouth for the purpose of locating 

 the locks and dams which are to be constructed by the Gov- 

 ernment, Assistant Engineer C. A. Locke discovered some 

 " blue roots " embedded in a stratum of clay which had been 

 exposed in the bank made by the erosion of the waters in 

 cutting out the channel of the river. The locality was about 

 two miles above Eddyville, Ky. The stage of the river was 

 about six feet above low water mark, and the stratum contain- 

 ing the roots was about two feet above the surface of the water 

 or eight feet above low water. The stratum is exposed there- 

 fore only for a limited season each year. 



Maj. Locke gives the general characters and thicknesses of 

 the strata exposed in the cut, as follows : Soil, 2 feet ; light 

 yellow clay, 15 feet ; light drab clay, 15 feet, at the bottom of 

 which the blue roots were found ; below this an unknown 

 depth of gravel. 



The " blue roots " were found in such position as to indicate 

 that they were in the place of their growth. The clay is 

 described as having a blue color when wet, and I regret that a 

 specimen of it was not collected for examination. 



Four of these " roots," more or less perfectly preserved, 

 were handed to me. They were from one-half to two centi- 

 meters thick and six to twelve long. The blue mineral which 

 has almost wholly replaced the woody fiber of the roots is of a 

 deep blue color resembling cobalt-blue but somewhat darker, 

 and of a duller hue. It is earthy and very friable. There is 

 no evidence of structure, and the specimens seem to be casts of 

 the original roots, formed gradually as decay proceeded. 



Some of the remaining particles of the wood were given a 

 microscopic examination by Professor Jas. M. Safford, who 

 pronounced it coniferous. 



