224 DR. THOMAS STERRY HUNT ON THE 
Montalban series would seem to show that these are remaining portions of great distinct 
and uncfhformable series, once widely spread out over a more ancient floor of granitic 
eneiss of Laurentian age; but, that the four series thus indicated include the whole of the 
crystalline stratified rocks of New England, is by no means affirmed. How many more 
such formations may have been laid down over this region, and subsequently swept away, 
leaying no traces, or only isolated fragments, we may never know ; but it is probable that 
a careful study of the geology of New England and the adjacent British provinces, may 
establish the existence of many more than the four series above enumerated.” * 
TABLE SHOWING THE STRATIGRAPHICAL RELATIONS OF THE TACONIC Rocks. 





Laurentian. Norian. Arvonian. 


Eaton’s Nomenclature (1832.) Later Names. 
8 | Corniferous Lime-rock.....,.......... Upper Helderberg..... Devonian. 
A 3. 
me 6 Geodiferous Lime-rock............... Niaoaraee es terre 
BB ee ; : ¢ Silurian. 
| Millstone-grit. . . } Second { Oneida—Medina .... 
= | 1. Graywacke-slate Graywacke. Utica—Loraine...... 
5 : Ordovician. 
Metalliferous Lime-rock......7....... Chazy—Trenton .... (Upper Cambrian) 
a. ; 
Zz Sparry Lime-rock. Calcifer. Sand-rock. j 
GE al 
ei] 2 ‘ Millstone-grit... | First Upper Taconic. Cambrian. 
A 2. Gray on A. Gray wacke. (Quebec Group) (Middle and Lower Cambrian) 
i Argillite a 1619 \6 vale ve vas ae pee 01e wists, se ] 7 
a |3 Granular Lime-rock................. Lower Taeonic.; Taconian. 
z (Itacolumitie Group) 
= 5 2, Granular Quartz-rock............ so... |] | 
& |1. Gneiss and other Crystalline Rocks... { Huronian. Montalban. 


III—GEOLOGICAL STUDIES IN PENNSYLVANIA. 
$ 19. The reader’s attention is now called to the two districts in Pennsylvania men- 
tioned in § 14; where the present writer has been enabled to confirm the observations of 
Vanuxem. To the west of the Susquehanna, in Mifflin county, is the Kishacoquillas | 
valley, an eroded anticlinal valley, having a rim of Oneida sandstone, (the Levant or No. | 
IV. of Rogers), which is the summit of the Second Graywacke of Eaton, and is conformably 
overlaid, on both of the monoclinal slopes, by the Medina and Clinton beds. Passing down- 
wards from the massive sandstones of the rim to the centre of the valley, we find alterna-_ 
tions of sandstone-layers with sandy shales, succeeded, in descending order, by the Utica — 
slate and the Trenton limestone ; all of which are well characterised, both lithologically 
and paleontologically. The whole series, from the summit of the sandstone to the base of | 
the limestone, here presents apparently one unbroken stratigraphical succession, corres- 

à 
* Hunt, Chemical and Geological Essays, page 281. 

