34 KANSAS CITY REVIEW OF SCIENCE. 
two of these masses on either side will be seen the layers of mica between which 
the iron was found. Much of the mound over the altar was formed of ferrugin- 
ous clay, and water in percolating through this clay would become impregnated 
with iron, which would be retained in the cavities formed in the material upon 
the altar over the hard-burnt clay. Bog iron might also be derived from the 
bituminous coal, clinkers and ashes from the fire upon the altar. This explana- 
tion accounts to me for the supposed rusted iron sword found in the Marietta 
mound in 1819 by Dr. Hildreth, which has been a puzzle to archseologists ever 
since. The silver-plated bosses, supposed by Dr. Hildreth to have been orna- 
ments of the sword scabbard, are also fully accounted for by similar silver-plated 
objects from this mound. 
Numerous mica ornaments were found in two of the mounds. They were 
cut from thin sheets of mica in various designs, conspicuously some like the head 
of some animal, one like a serpent, and one like a human head caricatured with 
a big nose and open mouth. The mica from which these ornaments were cut was 
probably North Carolina mica, which is known to have been mined before the 
settlement by the whites. 
Besides one copper implement, copper occurred in great abundance in these 
mounds. Two of the mounds contained masses of native copper, and several 
contained many ornaments of various designs, cut from hammered copper. 
Many spool-shaped ornaments occurred with pendants, bracelets, rosettes, and 
scrolls. Several large sheets of copper, full of round holes cut at regular inter^ 
vals, were found upon the altar of the large mound. A few copper ornaments 
were plated with a thin layer of hammered silver, neatly and closely applied to 
their surface by hammering. A bracelet and several of the spool-shaped orna- 
ments were plated in this way. It is to these silver-plated spool-shaped ornaments 
that I refer the so-called bosses on the sword scabbard described by Dr. Hildreth. 
The copper objects were all made from the native metal, which, while it may have 
been picked up in masses from the glacial drift, was more probably mined at Lake 
Superior, and the small quantity of native silver used in plating a few of the orna- 
ments leads to the belief that the copper and silver were brought from Lake 
Superior. Besides ornaments of mica and copper, there was obtained, for the 
first time from a mound, an ornament made of buffalo horn. 
There were found implements made of flint, and arrow points of quartz, of 
chalcedony, and of obsidian. Obsidian is not found to-day in this region, nor 
nearer to it than the volcanic regions of the Rocky Mountains, where tl:ie Indi. 
ans still use it for making arrow-heads. Spearhead-shaped ornaments were made 
from a mica schist, by a peculiar method of working the stone, such as I have 
never before seen. 
Several stone images were elaborately carved and grooved on the under side. 
These were more or less fractured by the great heat to which they had been sub- 
jected. In this small tray are what might be termed the gems of North American 
pottery. The little figures represent in clay the dress of the people, with the 
peculiar head-dress over the forehead, the large ear ornaments and the peculiar 
