240 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1902. [bull. 213. 
ward directly into the unchanged carbonate. This is well shown in 
the Sugar Hill deposits, later discussed. From the distribution of the 
ore banks it will be seen that a large proportion of them are located 
near the contact of the Beaver limestone and the Weisner quartzite. 
These generally belong to this class of concentration ores ; and this 
contact is marked by a more or less continuous band of ore deposits. 
The red clay in which they are embedded is chiefly derived from the 
limestone; and the surface is generally covered with fragments of 
quartzite from the higher portions of the quartzite ridges. 
4. As already remarked, the quartzite has been considerably folded 
and is doubtless also intersected by numerous faults of small throw, the 
evidence of the faulting being chiefly the occurrence of breccias. The 
latter usually consist of fine angular fragments of quartzite cemented 
by limonite; and associated with these breccias are often found con- 
siderable deposits of iron ore. These are sometimes irregular deposits 
embedded in the residual material which covers the surface, and are 
not sharply differentiated from the concentration deposits above 
described. In other cases, the ore appears to form well-defined fis- 
sure veins, with distinct walls of the inclosing formation. This is 
notably the case at the Wheeler bank, about 4 miles southeast of Car- 
tersville. The vein is from 12 to 15 feet in width, with occasional off- 
shoots. The inclosing rock is a gray siliceous schist, with some blue 
curly talcose slate and quartz stringers; also occasional bands of 
schistose deldspathic conglomerate. The vein dips east about 80° and 
strikes neatly north and south, parallel with the schistosity of the 
inclosing rock, and with the adjacent Cartersville fault. The ore 
appears in part to have filled an open fissure and in part to have 
replaced the schist, numerous fragments of which remain in the ore 
body. It consists for the most part of geoidal shells, containing many 
cavities with stalactitic and botryoidal forms, which have glazed sur- 
faces showing brilliant iridescent colors. It generally has a fibrous 
structure, and further differs from the concentration deposits in the 
almost complete absence of residual clay associated with the ore. 
This ore body has evidently been deposited subsequent to the devel- 
opment of schistosity in the inclosing rocks, since it shows no evidence 
of movement in the way of brecciation or slickensides. 
At no point in this district has development gone below water level. 
The deposits are generally worked only to a depth permitting direct 
drainage. Hence, the bottoms of the ore bodies are seldom reached. 
Of the depth to which the our classes of deposits enumerated above 
extend, it may be stated (1) that the gossan ores are sharply limited 
by water level; (2) that the Tertiary gravel ores are generally super- 
ficial, the greater part of the deposits being near the surface, below 
which they rarely extend more than 30 feet; (3) that the concentra- 
tion deposits go considerably deeper, and, under favorable conditions, 
may extend to the depth of 100 feet or even more, and (4) that the 
