METEORITES OF NORTH AMERICA. 317 



undoubtedly all originated by crystallization in the positions they now occupy and have not suffered at all from dynamic 

 agencies. The coarser portions of the rock, and particularly those in immediate juxtaposition with the metallic iron, 

 have a strongly marked cataclastic structure, the feldspars existing mainly as angular fragments. All structural features 

 point to the injection of the metallic iron, or at least to its reduction to the metallic state, subsequently to the solidifica- 

 tion of the stone, the same being accompanied by a shattering and more or less displacement of the minerals in the near 

 vicinity. In the more siliceous portions the iron exists only in small round blebs and seems to have been wholly 

 without effect on the structural features; but where existing in masses of some size the appearance is at once suggestive 

 of subsequent injections and consequent disruption of particles. 



The occurrence of the feldspars to the exclusion of the enstatites in the immediate vicinity of the metallic portions 

 would be extremely suggestive could we consider both as products of solidification in place, from an iron-bearing magma, 

 in the one case the elements combining to form an iron-rich silicate (enstatite) and in the other metallic iron and feldspar. 

 The extremely fragmental condition of the feldspars, particularly when closely associated with the iron, suggests, 

 however, that these were in a crystalline condition prior to the injection of the metallic portions, and hence that no 

 such extreme phase of magmatic differentiation could have taken place. 



It should be noted that the stone, as shown by sections cut from different fragments, is quite variable both in struc- 

 ture and in the relative proportions of its constituent minerals. 



The meteorite is distributed, Ward possessing 4,259 grams. 



BIBLIOGRAPHY. 



1. 1893: Eakins. A new meteorite from Hamblen County, Tennessee. Amer. Journ. Sci., 3d ser., vol. 46, pp. 283- 



285 (analysis) and 482. 



2. 1896: Merrill. On the composition and structure of the Hamblen County, Tennessee, meteorite. Amer. Journ. 



Sci., 4th ser., vol. 2, pp. 149-153. 



MOUNT JOY. 



Mount Joy Township, Adams County, Pennsylvania. 

 Latitude 39° 47' N., longitude 77° 13' W. 

 Iron. Coarsest octahedrito (Ogg) of Brezina. 

 Found 1887; described 1892. 

 Weight, 383.5 kgs. (847 lbs.). 



This meteorite was first described by Howell ' as follows : 



The Mount Joy meteorite, the third largest meteorite found in the United States, and the largest east of the Missis- 

 sippi River, was found in November, 1887, on or about the 16th of the month, by Jacob Snyder, about a foot below the 

 surface while digging to plant an apple tree near his house, 5 miles to the southeast of Gettysburg, in the township of 

 Mount Joy, Adams County, Pennsylvania. It was supposed by the finder and his friends to indicate the near presence 

 of an iron mine, and considerable prospecting was done to locate it. The meteorite was placed on some timbers in the 

 open air, where it remained until the summer of 1S91 before it was seen by anyone who surmised its true character. 



Prof. F. W. Clarke induced Mr. Snyder to send it to the National Museum for inspection, but was finally unable to 

 secure it, as Mr. Snyder was unwilling to part with it for a price which the museum felt justified in paying. I, therefore, 

 purchased it from Mr. Snyder on August 15, 1891. The three largest dimensions of the meteorite are 11, 24, and 33.5 

 inches and it weighed on the museum scales 847 pounds. Professor Clarke had a few ounces taken off for examination; 

 with this exception and the scaling of decomposed crust from the outside the mass still remains as it was found. 



Professor Clarke has kindly furnished mo with the following analysis, made by Mr. L. G. Eakins in the laboratory 

 of the United States Geological Survey. 



Professor Clarke did not succeed in developing the Widmanstatten figures satisfactorily, and the small amount of 

 nickel shown by the analysis would indicate a poor etching iron; when larger surfaces are available we shall doubtless 



obtain better results. 



Fe Ni Co Cu P S 



93.80 4.81 0.51 0.005 0.19 0.01 =99.325 



No idea can be formed of the length of time the meteorite had lain in the ground and very little of the amount of 

 surface decomposition; it has undergone sufficient, however, to remove all the finer pittings, leaving a comparatively 

 smooth surface. 



Having been much interested in Mr. Davison's examination of the magnetic properties of the Welland meteorite, 

 and thinking that this line of investigation in other meteorites might lead to interesting results, I requested Mr. Marcus 

 Baker, of the United States Geological Survey, to make an examination of the meteorite, which he kindly consented 

 to do. 



The result of this examination is to show that the meteorite, as a whole, acts as a mass of soft iron, gaining polarity 

 under the inductive action of the earth. The lower portion on the north side became a north-seeking pole, while the 

 upper part became a south-seeking pole; a pretty distinct neutral line was shown, inclined to the horizon at an angle 

 (20°-25°) which is approximately the complement of the local inclination of the dipping needle. This induced polarity 

 shifted with each change in the position of the whole mass, and in general this shifting of the poles took place promptly 

 though not always at once. Mr. Baker also Btates that his observations suggested the probable existence of an unequal 

 distribution of permanent magnetism, but this matter requires further investigation. 



