130 
THE TERTIARY GEOLOGY OP THE 
division info the “lower” and “middle Atlantic Miocene,” or what I have designated 
the “ Mar)’landian ” and “ Virginian,” does not, however, appear to be as distinctly 
marked oflf as in that State, the fossils indicating a more nearly uniform age (Vir- 
ginian), hut this seeming divergence may possibly be attributed to imperfect observa- 
tion, or to a lack of observation. The discussion of the age of the beds here referred 
to, as well as of the equivalent deposits of Maryland, and their relations to the French 
faluns and the older Tertiary deposits of the Vienna basin, is fully set forth in my paper 
“ On the Relative Ages and Classification of the ])Ost-Eocene Tertiary Deposits of the 
Atlantic Slope” (Proc. Acad. Xat. Sciences of Phila., June, 1882). It is not unlikely 
that the extremity of the State lying south of the James River, and including partly 
or wholly the counties of Southampton, Isle of "Wight, Nansemond, Norfolk and 
Ihincess Anne (with the towns, among others, of Wakefield, Smithfield, Suffolk and 
Norfolk), as well as the extremities of the peninsulas included between the James, 
■^'ork and Rappahannock Rivers, belongs to a somewhat newer period than the region 
lying farther ’to the west, or more nearly that represented by the later Tertiary 
deposits of North and South Carolina — the “ Carolinian ” or upper Atlantic Miocene 
whos(? continuation appears to be found here. The “ fragmentary rock,” consisting 
largely of comminuted and clo.sely cemented shell fragments, described by Rogers* as 
occurring at various points on the eastern portion of the Miocene district, at Yorktown 
and llellcficld on the York River, and “near the extremity of all the iieninsulas,” and 
whcn'ver occurring forming a distinctive feature in the stratigraphy of the region, is 
an indication of this newer formation. The existence of a newer division of the post- 
Koccne 'I’crtiary in southeastern Virginia, although erroneously referred to the 
“ Medial Pliocene,” was alre'ady indicated by Conrad in 1835,t who assigned as 
localities lor the same Yorktown, Suffolk and the James River near Smithfall 
(Smithfield ?). A somewhat .similar division of the Tertiary is made by Rogers who 
however, refers the newer division, with West Point, Norfolk, Suffolk, YVakefield’ 
etc., to the Pliocene.J 
One of Ihe most interesting components of the Virginia Miocene formation is the 
h 0x1“ ‘'■'""T;!'™'" “ ■ievelopment in some places of 30 feet, which 
tl.e I aso ofT' ’'iotao'xi earth ”) and Petersbnrg, and which lies near 
1 1 , di r f", : ' of Miocene shells, ;vhich 
1 am Tolr r" “"“T- “> *o-P tnxen. 
ling m Fm 1 Md.. and has been s.rnck in an .artesian 
upon the Pocono ^ " w'T “l '*'*’*'' likewise resting 
* Rvp. Owl. Rooonn., 1836, pp. 33 _ 4 . 
f Am. Joum. Science and Arts, xxviii, p. 106. 
t Macfarlane’s “Geological Railway Guide,” ISia p. 184. 
t Rogers, in Macfarlana’s Guide, p. 183. 
