i'no('/:icniX(;s of the x. it/ox il miskum. 



2'^3 



n 



Tlic material from Albortou, Maiylaiid (No. (;2<i04, (T. S. N. M.), is 

 quite similar in j^cncial aitpoarancc to tiiat from (Jlcvclaiid, (xm-ui ring 

 ill tlic foiiii of librous buiidk'.s 1- to 18 iiiclics iii lengtli. The iiidividual 

 liberty arc very smooth and polygonal in outline, and !j;iv<' parallel 

 extinctions. The ultimate composition, it will be observed, is essen- 

 tially the same as that of Nacoochee. ^Vnother variety, occurring in 

 the limestonejust above Alberton, is iiure white in color, finely librous, 

 and when wet is easily rediK-ed to a condition that can only be des(;ribed 

 as pulpy, like wet paper. The fibers extinguish always parallel with 

 the axis of elongation, but its exact mineral nature has not been as yet 

 worked out (see Analysis 40 in accompanying table). 



The Carbon County (Wyoming) material (No. 02090, U. S. N. M.) is of 

 the same general nature as No. ()2«)04. The material from ]\Iitchell 

 County, North Carolina (No. 5087(), U. H. N. M.), is in the form of bundles 

 of parallel-lying, long, soft and 

 silky fibers, white in color, 

 and easily reduced to a fine, 

 silky ])owder, without appre- 

 ciable grit, by rubbing be- 

 tween the thumb and linger. 

 The extinction colors are very 

 faint, but always jiarallelwith 

 the axis of elongation. No ap- 

 preciable pleochroism. The 

 fibers show occasional cross 

 Xiartings, causing them to 

 break with shari'), straight 

 fractures. The actual size of 

 the fibers — that is, the diame- 

 ter — is indefinite, since there 

 seems no limit to further sub- 

 division. The smallest actually measured was (».()()2 mm, Down to a 

 diameter of 0.00 1 mm. the fibers are of quite uniform diameter through- 

 out tlieii- length and in the form of square or slightly compressed 

 prisms (see Figs. 1 and 2). The smaller sizes frequently tajier off to 

 wedge shaped ibrms, as shown in Fig. 3. All show extinctions and 

 ])lane of o[)ti<i axis parallel with the axis of elongation. 



Two samples were examined, labeled as from Franklin County, 

 North (Carolina, The first, from the Brush collection at New Haven, 

 kindly submitted by S. L. Penfield, was in the form of somewhat 

 stiff and brittle bundles of a slight brownish color. The material was 

 easily reduced to fibrous form by thumb and fingers, but the fibers were 

 quite brittle. Its composition is that of normal anth()])hyllite, closely 

 resembling that of Mitchell County, above noted. The second sample 

 (No. 44232, U. S. N. M.), concerning the identity of which there at first 

 seemed some doubt, proved microscoijically identical and was not 

 analyzed. 



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