270 The American Geologist. Novenaxir. i89« 
metallic surfaces' this striation runs in the same direction, 
but in the bands at a it is at a different angle with the 
grand structure. This striation, in like manner, consists of 
dark ridges separating metallic grooves. They seem to differ 
from the coarse s^triicture only in being much finer. Thus 
this iron has not only a coarse Widmanstiittian crystallization, 
each band being, as it were, an individual crystal, but it has 
what might be considered a fine cleavage and a minute inter- 
nal structure, which, throughout the separate crystals, main- 
tains its direction and individuality. 
These finer markings suggest those described by J.Law- 
rence Smith and named Laphamite marks,* but they seem to 
differ from the-m in an important manner, if they be compared 
with the description published by Smith, 3^et there is no doubt 
that they both ai*e due to a fine internal structure of the iron 
itself. The reflecting cleavages do not indicate any variation 
in the composition of the iron and are more likely to represent 
the markings noted b}' Dr. Smith, but the dark elevated 
ridges, both coarse and fine, are apparently of a different 
chemical compoteition. 
An analysis was made by F. F. Sharpless, and the following 
was the result : 
•' -Analysis of the Arlington Iron. 
Sulphur. ..;.... none 
Silicon none 
Manganese none 
Chromium trace 
Copper /. trace 
Carbon (combined) trace 
Iron 90.781 
Nickel.. , 8.605 
Cobalt ■ 1.023 
PliosphoniK . .' 0.045 
100.454 
Mr. Sharpless adds : 
The only way in which I can account for the excess over 100 per cent, 
is that the composition does not appear to be uniform. Four determi 
nations were made for iron, giving results varying from 90.58 per cent, 
to 91.74 per cent.- " In the attempt to make a carbon determination the 
variation in composition was also noticed. Of three samples, weighing 
about-three grammes each, treated with potassium-copper chloride, one 
" *Am. Jour. Sci. (2), xlvii, 271; ibid. (3), x, 351. 
