PETROGRAPHIC CHARACTER OF OHIO SANDS 161 
in the older sandstones, these questions arise: Is it due to the 
inability of garnet to withstand solution and decomposition 
incident to weathering? Is garnet sufficiently resistant to the 
wear of travel to find a place in sands laid down at a distance from 
the source of supply? Or is the scarcity due to the derivation 
of the components of the sandstone from a region where garnet 
was not an important rock-forming mineral ? 
There is ample evidence that garnet is quite resistant to ordinary 
weathering processes. It is a common constituent of residuary 
sands derived from decomposed schists. The Newark series of 
New Jersey and Connecticut, consisting largely of coarse sand- 
stone which would favor free circulation of ground waters, has been 
exposed to weathering processes for many ages; nevertheless it 
contains abundant garnet grains which show little evidence of 
solution or alteration. Furthermore the discovery of occasional 
particles in a few of the older Paleozoic sandstones is still stronger 
proof of the resistant properties of garnet. The scarcity cannot 
be due to mere decay since often other minerals survive which are 
equally or more susceptible to decay, such as feldspars and mica. 
The physical properties of garnet are such that it should with- 
stand the wear of long travel. Lack of cleavage, and hardness are 
in its favor. Zircon, tourmaline, feldspars, and other minerals 
which are somewhat similar in their physical properties to garnet 
are widely distributed even in the very old sandstones. 
This leads to the conclusion that the materials of the older 
sandstones were derived from sources where garnet was not abun- 
dant. Repeated reworking of successive sandstones has doubtless 
furnished much of the material. Very pure quartz sands of the 
Sylvania type are probably entirely derived in that way. However, 
most of the great sandstone formations have constituents which 
have certainly come rather directly from crystalline areas. ‘This 
is especially true of the Catskill series and the “Coal Measures”’ 
sandstones. 
- Garnet is a characteristic mineral of regional and contact meta- 
morphism. It is common in gneisses and schists of sedimentary 
origin. As an original mineral in igneous rocks it is much less 
common. ‘The gneisses and schists of the Appalachian region are 
