458 ADDRESS OF T. STERRY HUNT. 
northern district, and to consist chiefly of white feldspathic and 
dark hornblendic gneiss, with very little mica, and with crystalline 
limestones. 
The gneiss of the third or southern district, that lying to the 
south of the Montgomery and Chester valleys, comes from beneath 
the Mesozoic of New Jersey about six miles northeast of Trenton, 
and stretching southwestward, occupies the southern border of 
Pennsylvania, extending into Delaware and Maryland. It is sub- 
divided by Rogers into three belts; the first or southernmost 
of these, passing through Philadelphia, consists of alternations of 
dark hornblendic and highly micaceous gneiss, with abundance 
of mica-slate, sometimes coarse-grained, and at other times so fine- 
grained as to constitute a sort of whet-slate. To the northwest- 
ward the strata become still more micaceous, with garnets and 
beds of hornblende slate, till we reach the second subdivision, 
which consists of a great belt of highly talcose and micaceous 
schists, with steatite and serpentine, and is in its turn succeeded 
by a third, narrow belt resembling the less micaceous members 
of the first or southernmost subdivision. The micaceous schists of 
this region abound in staurolite, garnet, cyanite and corundum, 
and are traversed by numerous irregular granitic veins containing 
beryl and tourmaline. All of these characters lead us to refer the 
gneiss of this southern district to the third or White Mountain 
series, with the exception of the middle subdivision, which presents 
the aspect of the second or Green Mountain series. 
Above the hypozoic gneisses Rogers has placed his azoic oF 
semi-metamorphic series, which is traceable from the vicinity of 
Trenton to the Schuylkill, along the northern boundary of the 
southern hypozoic gneiss district. This series is supposed by 
Rogers to be an altered form of the primal sandstones and slates, 
and is described as consisting of a feldspathic quartzite or eurite, 
containing in some cases porphyritic beds with crystals of feldspar 
and hornblende, together with various crystalline schists ; includ- 
ing in fact the whole of the great serpentine belt of Montgomery, 
Chester and Lancaster counties, with its steatites, hornblendic, 
dioritic, chloritic, and micaceous schists (often garnet-bearing)s 
together with a band of argillite, affording roofing-slates. With 
this great series are associated chromic and titanic iron, and ores 
of nickel and copper. Veins of albite with corundum also inter- 
sect this series near Unionville. We are repeatedly assured by 
