METEORITES OF NORTH AMERICA. 39 



Professor Darby described the mass as consisting of agglutinated, irregularly shaped con- 

 cretions, as if suddenly compressed together into a single rounded mass from a previous state 

 of separation. 



Professor Darby states, as quoted by Shepard: 1 



The man who brought it to me (and who was ita discoverer) had taken it, without my knowledge, to a black- 

 smith's shop, where in the cold state it was broken in two upon an anvil by means of a sledge hammer. Originally it 

 must have been nearly globular in form. The surfaces produced by the separation had, when I received the specimen, 

 a metallic luster. The finder made known to me the exact spot where he had ploughed it up. It was on what is known 

 as the Daniel plantation, about three quarters of a mile west of our college building, and near the eastern edge of a field, 

 just across a branch (a small stream) . I have searched in the region indicated for further specimens without effect, but . 

 have instructed the negroes to bring to me anything unusual which they may hereafter discover. The name of the 

 man who found the mass and his present address are unknown. 



According to Shepard 1 



The surface of the fracture, or separation, is coarsely granular, exhibiting large irregularly shaped concretions, 

 which show only obscure traces of octahedral cleavage. The former metallic luster is now replaced by a rusty brown 

 film; while numerous cracks or chinks are observable, not merely separating the concretions, but often traversing the 

 mass of each individual. Indeed the entire specimen is thus cracked up and subdivided by these open veins as if it 

 had been shattered when in a semifused state by striking against a rock at the time of ite fall. So imperfect is the 

 cohesion at present that it would not be very difficult to break it into pieces (from the size of a large pea up to that of 

 an almond) by vigorous blows from a sledge hammer. Some of these concretions are partially stalactitic, tuberose, or 

 submammillary, as if a secondary softening or fusion of the iron had taken place at the time of its descent. 



The larger concretions have a tendency to separate into smaller ones of the size of peas, whose figure, however, 

 is that of the granular individuals of magnetite and pyrites, except perhaps, in the tendency to elongation in the con- 

 cretion which occasionally passes into the subcolumnar structure. One single troilite globule half an inch in diameter 

 is visible upon the fractured surface of the mass. It is compact in texture and yellowish brown in color. A polished 

 surface half an inch square on being etched gave a series of markings extremely fine and delicate in their dimensions, 

 and requiring a strong light, with the aid of a microscope, to be seen with distinctness. The first character that displays 

 itself is that of a mesh or network, arising from the polygonal boundaries of the granular concretions. The areas within 

 these lines or edges (which are exceedingly thin) have a glittering luster when held at a fixed angle to the light, though 

 this angle often varies for different concretions. The second character of interest is the finely striated surface of each 

 concretion, one set of lines being perfectly straight and equidistant, while a second set, less distinct, cross these at right 

 angles. The final peculiarity of the markings is that these fine stria are wholly made up of dots or beads, which 

 are arranged in almost absolute contact, and are therefore to be regarded as consisting wholly of sections of rhabdite 

 needles, while on the other hand, the mesh-like markings first noticed are composed of plates of schreibersite. 



The iron is classified by Brezina 5 as a normal hexahedrite. Analysis by Shepard * of about 



2 grams gave: 



Fe. Ni. P. Insol. Mg., Ca., Si., & loss 



94.58 3.015 0.129 0.523 1.753 =100 



Sp. gr., 7.0-7.17 (mean 7.05). 



Shepard notes that neither cobalt, tin, nor copper was detected in this iron, a statement 

 which Smith 2 criticises as questionable. Cohen * also remarks that Shepard's analysis of Auburn 

 needs revision. 



Cohen 8 gives a further description and analysis as follows : 



According to the description of Shepard it seems probable that Auburn should be considered a granular hexahedrite, 

 but since neither the piece in Vienna, nor the material accessible to me indicates such a structure I place Auburn 

 among the normal hexahedrites. It etches easily and shows abundant Neumann lines first visible under the lens. 

 These lines frequently intersect and, as usual, some systems are distinguished by their length. Numerous uniformly 

 distributed pits are present which may be referred in considerable number to rhabdite lying perpendicular to the plane 

 of the section. Further, there appear on an etched surface, dull, dark, dimly bounded spots. Minute, dull, dark flakes 

 which could not be further determined lie between the pits. They are, perhaps, carbonaceous particles. Larger 

 inclusions of schreibersite are only sparingly present in the form of grains and rod-like crystals. Particles of iron glass 

 lie on the edge, and a thin rust crust forms the natural surface. Since single spots in the neighborhood of the latter 

 rust easily, the iron can not be, as Shepard states, free from chlorine. 



Analysis by Hildebrand : * 



Fe. Ni. Co. Cu. Cr. P. S. 

 94. 49 4. 67 1. 03 0. 101 0. 024 0. 46 0. 002 =100. 777 



The iron of Auburn is somewhat distributed, but the whereabouts of much of the origiually 

 reported quantity is not known. 



