Ko. 2341. THE ESTHERVILLE, IOWA, METEORITE— MERRILL. 367 



Tlie above-described features, with sundry others to be noted, 

 are suggestive of conditions through which the meteorite has passed, 

 which have not received recognition by previous writers and which 

 will, therefore, be considered in some detail here. 



One of the most striking features of the stone on casual inspection 

 is its slag-like appearance, even in the interior portions. This was 

 noted by Von Rath,^ who describes it as highlj' remarkable on 

 account of the numerous cavities, upon the walls of which small 

 individual (and obviously secondary) crystals have form^ed. Smith 

 also in his description wi'ote:^ 



Another striking feature in the relation of the iron and stony matter is that the larger 

 nodules of iron seem to have shrunk av.-ay from the matrix, an elongated fissure of 

 from 1 to 3 mm. sometimes intervening, separating the matrix and nodules to the 

 extent of one-half the circumference of the latter and appearing as if the iron had 

 contracted from the stony matrix diuing the process of cooling. There are numerous 

 small cavities of various sizes where there are no iron nodules, and where the miner- 

 als appear more crystalline, indicating an irregular shrinkage during the consolida- 

 tion. 



No other explanation is, however, attempted. 



An examination of the stone in thin sections brings out at once 

 the fact that though the ground is holocrj^stalline few of the larger 

 constituents present outlines to suggest that they result from cvjs- 

 tallizmg freely from a m.olten magma. (See figs. .3, 4, and 5, pi. 22.) 

 Both the pyi-oxenes — enstatite and '' peckhamite " occur in angular 

 or rounded pebble forms, as does also the diallage, and as shown in 

 plate 23. It is obvious, too, I think, that quite aside from this, two 

 minerals similar in composition but dissimilar in color and ph3'sical 

 characteristics, as are the first mentioned, could not both have 

 originated from the cooling of the same magma and in the positions 

 they now occupy (figs 3 and 4, pi. 22). It is to be noted further that 

 the larger masses of olivine, or pyroxene, whichever they may be, 

 have a distinct fragmental or pebble-like aspect.'' (See Nos. 1, 

 2, and 3 on pi. 24.) That of the "peckhamite" in the Yale speci- 

 men and in the slice belonging to the University of Minnesota is 

 also mimistakable.* These forms often shov/ on a polished surface 

 numerous fine points of metal which are lacking in the granular 

 ground in which they are imbedded and which serve to still further 

 differentiate them. 



The form and crystallographic condition of the feldspathic con- 

 stituents are often peculiar. Two distinct forms are recognizable 

 in the rock, the one occurring in fairly large plates for the most part 

 clear of inclosures, limpid and with extremely irregular outlines 



» Verhandl. Natur. Hist., Vereine, Bonn., vol. 37, 1880, p. 239. 



2 Amer. Journ. Sci., vol. 19, 1880, pp. 559-463. 



3 One of these pebble forms in the Yale University specimen is 8 cm. in greatest diameter. 



* Smith notes in his description of the mineral that " small romided nodules, several millimeters in size, 

 are found in the interior of the mass, sometimes of irregular form," etc. 



