14 Tlie A)liei'lCCni (reojogiiit. -July, 1892 
tlunr base. The name is taken from MartinsV)urg, in tlie Shenan- 
doah valle}" in West Virginia, a region in wliich the formation is 
extensivel}' and typically exposed. Its largest areas are in the 
great syncline of the Massanutten mountains, and the long nar- 
I'ow area bordering the great valley on the west along the flanks 
of Little North mountain. The rocks are slates and shales, 
mainly of dark color; in the Massanutten s^'neline thin beds of 
sandstone are included, and occasional limestone beds or calcar- 
eous streaks occur at other localities. The beds are fossiliferous 
at many points; graptolites are found in the basal beds, notably 
in some light colored weathered shales in cuts of the Chesa- 
peake & Ohio railway, two miles east of Staunton and further 
east; along the Little North mountain, and in the Warm Spring, 
Crab Bottom and other anticlinal valleys westward, remains of 
upper Ordovician brachiopoda are moderately abundant. The 
forms most frequently met with are Leptana serlcea^ L. alUr- 
iKitd, Ort/n's test luTinar 1.(1. 0. pecfiiteJId, and Modiolopsis modio- 
Jarla. The precise equivalency of the formation is not known, 
but judging from its general relations and fauna itprobablj^ com- 
prises the Utica, Hudson River, and possibly small amounts of 
adjacent formations of the New York series. It is the No. Ill 
of Rogers' reports and has generally been called "Hudson River. " 
The Massanutten sandstone receives its name from the promi- 
nent Massanutten mountains in which it is typically developed. 
It also constitutes the Little North mountain, and many other 
prominent ridges in Appalachian Virginia. 
The rocks of the formation vary in local characters, mainly in 
color, thickness of bedding and degree of silicification, but 
w^hite and red quartzites prevail. In most sections the basal beds 
are alternating beds of dark sandstones and shales; these are 
succeeded by white and grey quartzites, which in turn give place 
to thinner bedded red and brown sandstones and shales. The 
formation was separated into two portions, numbers IV and V, 
by Rogers, the lower part supposed to be equivalent to the Medina 
sandstone, and the upper shaly series to the Clinton, Niagara and 
Salina of the New York series; but while this subdivision may 
be practicable in some sections of the state, it would be most 
arbitrary and variable in the region to which these notes relate. 
The fossil ore horizon containing a Clinton fauna is not well 
developed in the region west of Staunton, and fossils are rare 
