Review ot Recent Geological Literature. 5.1 
to a brownish or buff color, together with some bands of dark-colored 
thin limestone, with a total thickness of about 500 feet. The lime- 
stones contain Agoniatites expansus (Vanuxem) which is so char- 
acteristic of a thin limestone in the lower part of the Marcellus 
shale in New York that its generic name has been given to it, while 
the black shales contain numerous specimens of Liorhvnchus limi- 
tare (Vanuxem) and some other species which are regarded as 
characteristic of the New York Marcellus shale. In a general way 
this member corresponds with the Marcellus shale of New York 
with which it has been correlated. The upper member is composed 
of bluish or bluish-gray shales and sandstones with an approximate 
thickness of 1,100 feet. This member contains numerous specimens 
of characteristic Hamilton species of New York and frequently the 
entire 16 species which professor Williams has previously listed as 
the "dominant species of the Hamilton formation of eastern New 
York and Pennsylvania." Evidence indicates that the deposits of 
the Romney formation in Maryland apparently closed at about the 
same geological time as the Hamilton beds of New York, and in a 
general way this member has been correlated with the Hamilton 
beds of New York. It is not intended to state that the limits of 
the Romney formation in northern West Virginia and Maryland are 
exactly contemporaneous with the limits of the Erian series of New 
York; but there is a striking similarity in most details and it is 
believed that there is no serious error in this general correlation. 
The deposits, called Romney shale, which professor Williams 
has studied in the field, their fossils, in the laboratory, and , dis- 
cussed in Bulletin No. 244 are located in southern Virginia and 
eastern Kentucky. These collections later were supplemented by 
others made by Dr. Kindle in Kentucky, Virginia and southern 
West Virginia. It appears, however, that the locality farthest 
north from which collections were made is 110 miles or more to the 
southwest of Romney and, apparently, the nearest outcrops of the 
so-called Romney shale which professor Williams studied in the field 
are 220 miles or farther to the southwest of that town. It is well 
known that there is a rapid thinning and marked lithologic change 
in the Devonian deposits as they are followed from the Potomac 
basin to the southwest. Professor Williams' own statement "that 
in the correlation of local formations the same species of fossils 
alone (when so much as 50 miles of distance separates their sta- 
tions) can not be relied on for establishing more than a general 
homotaxial relation of the formations compared"* would suggest 
caution in correlating with the Romney formation the deposits of 
Bland county in southwestern Virginia, 220 miles to the southwest. 
The statement of professor Williams that "the rocks belonging to 
the part of the column called Romney, in central and southern Vir- 
ginia, contain chiefly the faunas found in New York in the Mar- 
cellus, Genesee, and Nunda ('Portage') with only traces of the Ham- 
* Bui. Geol. Soc. Amer., vol. 16, p. 147. 
