18 The American Geologist. juiy, issz 
rano(> of Hamilton group e(iiiivtilents in tho Romney shales is not 
{4)par(nit, and Hamilton (lei)osits probably extend some distance 
at>ove. 
In the Jennings formation very few 1ieds are fossiliferons, and 
the}- are mainly in the medial l)eds where Chemung and Portage 
forms occur comprising Spirlfcra disjuncta, S. nicsocosfa/is, Strrji- 
torhynchua chemungensix, Choiietes scifiihi, and others. 
The Hampshire formation has yielded only a few plant remains 
which throw no light on the e(juivalency of the formation, ])ut no 
doubt it comprises the representatives of the Catskill in their en- 
tirety or in greater part. 
The Pocono sandstone is apparently- the southern extension of 
the beds which bear the name in Pennsylvania. It is the No. X 
of Rogers. Its basal beds are coarse grained, quartzite sand- 
stones, sometimes conglomeratic, massively bedded, usually light 
grey in color, and always constituting either a prominent ridge or 
protecting mountain cap. Higher members are thinner bedded 
and dark in color, and contain layers of slate with thin irregular 
coal beds. These coals have been worked at some localities but 
usually without profit, for the beds are thin, irregular and gen- 
erally much crushed. Lower Carbonifei'ous plant remains occur 
in the coal-bearing slates but nomolluscan remains were observed. 
On the Staunton sheet the Pocono sandstone caps Elliott's knoli 
and various other high summits, particularly along the Shenan- 
doah mountains, and it also constitutes the high, narrow- ridge 
known as Narrow Back mountain. 
The Greenbrier limestone has been described with consideraljle 
detail by Rogers, and 1 have nothing to add to his descriptions. 
ON THE SIGNIFICANCE OF THE WHITE CLAYS OF 
THE OHIO REGION.* 
By FiiANK Leveuett. 
The fact has long been known that in southeastern Indiana and 
southwestern Ohio the southern portion of the glaciated district is 
covered to a depth of several feet by clays, distinctly different in 
color and structure from the underlying glacial beds, and from 
the surface portions of the glacial drift further north. In the In- 
*The work whose results appear in this paper was carried on under 
the supervision of Pres. T, C. Chamberlin, with whose permission this 
paper is published in advance of the more detailed official report. 
