Wright.] 
444 
[Jan. 1, 
ter being three one-thousandths of an inch (0.003 inch) = 76. 2 fi 
(mikrons). 
Second , red-brown scales of biotite, smaller than the quartz 
scales, averaging about two one-thousandths of an inch (0.0019 
inch) = 48.26 ;j. (mikrons) in diameter. The hexagonal angles are 
frequently distinct, though usually the margins are ragged. Al- 
though the flakes must all have been basal cleavages, nearly half 
of them showed some alterations between crossed nicols. 
Third. Small and large colorless flakes, always appearing iso- 
trope, some of them, possibly, of a volcanic, glassy nature, others 
showing a few sharp angles of 60 degrees and 120 degrees, doubt- 
less muscovite. 
Fourth. Opaque, red-brown flakes and aggregations of ferric ox- 
ide, showing gradations from a powdery ochre up towards scales 
of biotite, from which they were undoubtedly derived. 
Fifth. Very fine-grained material, having no distinct optical 
characters. In the dry powder it forms aggregations of a whitish 
color. It is, doubtless, kaolinic and forms the cement for the whole 
image. 
Nothing was detected which seemed to be of the nature of veg- 
etable tissue. 
The above analysis suggests at once, in fact, practically proves, 
that the material, as a whole, consists of the finer elements result- 
ing from the breaking up of granitoid rocks. 
SOURCE OF THE MATERIAL. 
Upon application to the parties who discovered the image, sam- 
ples were obtained: (1) of the surface soil in the vicinity of the 
well ; (2) of the sand from various depths in the well, taken, how- 
ever, from the dump heap where it had lain for three months ; (3) 
of the lava rock, taken from an adjacent well ; and (4) of clay balls 
which were said to have been first encountered at twenty feet above 
the depth at which the image was found. 
All of these have been examined to see if any of them could 
have furnished the material for the image. The surface soil will 
not make a clay that can be worked, and when burnt it falls to 
powder. The sand and the lava are also out of the question. It 
should be remarked, however, that the sand is a clean, whitish-yel- 
low sand, containing some mica scales and gravel, and is also of 
granitoid origin. The clay balls fit the case precisely, and I am 
