METEORITES OF NORTH AMERICA. 435 



THURLOW. 



Hastings County, Ontario, Canada. 

 Latitude 44 'Of N., longitude 77 20" W. 

 Iron. Fine octahedrite (Of) of Brezina. 

 Found 1888 (Berwerth); 1895 (Ward). 

 Recorded 1897. 

 Weight, 5.42 kgs. (12 Ibs.). 



This meteorite was first mentioned * so far as the present writer is aware in a brief prelim- 

 inary notice in the American Journal of Science as follows : 



The mass was found by Mr. E. S. Leslie, jr., May 12, 1888, on about the center of the 28th lot of the 6th concession 

 of the township of Thurlow, Hastings County, in the Province of Ontario. This meteoric iron, which would appear to 

 have been brought to the surface by plowing, is described by Doctor Hoffmann as an irregularly shaped, truncated 

 pyramidal mass, with a more or less rectangular base, measuring 16 by 13.5 or, including an elongated projection, 17 

 cm. in its diameters, and 10 cm. in height; its weight is 5.42 kgs. The entire surface is pitted and coated with a chestnut- 

 brown, slightly glimmering film of oxide of iron. 



Berwerth * mentions fine lamellation, likewise fine-netted plessite fields as characterizing 

 the meteorite. He classified it as a medium octahedrite. 



Cohen s groups the iron with the fine octahedrites and describes the structure as follows : 



The bands are for the most part grouped and surrounded with distinctly visible taenite. The longer bands are regular 

 in shape while the shorter are swollen both on the ends and in the direction of their length. The lamellae in part lie 

 close together and in part are separated by very small (j^ to \ mm . in width) elongated fields which, like the other fields 

 of narrower compass, consist of dark, compact plessite in which can be discerned on stronger magnification, as usual, angu- 

 lar shining flakes. In some fields of this sort may be seen, lying singly or isolated, complete lamellae, or the central part 

 of a field may be, through an increase in the number of the angular shining flakes, brighter than the narrow zone about it. 

 The larger fields show, even as well as the lamellae, a repetition of the coarser structure. Complete lamellae 0.02 to 0.1 

 mm. in width, and either singly or in groups, lie in the central part of the fields closely pressed together so that only 

 very small portions of the compact, dark plessite occur between them, although the latter rules the space toward the edge 

 of the fields. This produces a well-marked edge which gives a characteristic appearance. The small lamellae are not 

 outgrowths of the chief lamella;, at least as a rule, since they are generally swollen or acute wedge shaped, and often are 

 plainly inclosed in a tsenite shell. Evident outgrowths of the larger lamellae, however, also occur. The kamacite 

 appears coarse and cross-hatched both to the naked eye and under a lens. With a higher magnifying power, however, 

 one sees, both in the large lamellae and the small lamellae of the fields, that it has a dark streaked structure which as a 

 rule runs in one direction but also is much crossed. This occurs as black veins consisting of fine and coarse, irregularly 

 bounded threads which have the appearance of resulting from the extrusion of carbon-rich iron. The kamacite, there- 

 fore, appears darker and duller than usual; it gives no oriented sheen and is noticeably different from that of other 

 octahedrites. Among accessory constituents schreibersite is the most abundant. The smaller individuals of this 

 mineral occur in the form of grains and prisms embedded in the bands and cause a swelling of the latter where they 

 occur in quantity. The larger individuals are chiefly prismatic though irregular in shape and are surrounded by 

 swathing kamacite of the same character as the kamacite of the lamellae. I also observed, though but rarely, little 

 grains of troilite surrounded by schreibersite lying in the swathing kamacite. 



The following analysis made by Dr. O. Burger is given by Cohen:* I being the complete 

 analysis and la showing the composition of the nickel iron after deducting 0.14 per cent troilite 

 and 1.62 per cent schreibersite. 



Fe Ni Co Cu Cr P S 

 I 89.17 9.92 1.04 trace trace 0.25 0.05 =100.43 

 la 89.37 9.62 1.01 trace trace =100 



The meteorite is somewhat distributed but is chiefly in the possession of the Geological 

 Survey of Canada at Ottawa. 



BIBLIOGRAPHY. 



1. 1897: Amer. Journ. Sci., 4th ser., vol. 4, p. 325. 



2. 1900: BERWERTH. Meteoriten, Ann. K. K. Naturhist. Hofmus. Wlen. Bd. 15. 



3. 1905: COHEN. Meteoritenkunde, Heft 3, pp. 377-379. 



