3ii,s The American Geologist. December, 1898 
the typical Appalachian structure; it is composed of Silurian and De 
vonian rocks more or less closely folded. Beyond this is the Alleghany 
plateau of less sharply folded Devonian and Carboniferous strata. 
Here lies the coal industry of Maryland. The well known names and 
numbers of the Pennsylvania survey are used in the descriptions of 
the formations of the Paleozoic. 
The Coastal plain is composed of little consolidated or unconsoli- 
dated gravels, sands, marls and clays. A number of formations are rep- 
resented, as follows: 
(Pleistocene (Columbia). 
I 'enozoic - 1 pliocene (Lafayette). 
' >"'-°' c Miocene (Chesapeake). 
Eocene (Pamunkey). 
Mesozoic x Cretaceous 5 Upper (Severn). 
Mesozou ^retaceous f Lower (p otomac ). 
Of these the Pamunkey and Chesapeake are of special interest 
because of the large numbers of fossils to be found in them; these 
Eocene and Miocene fossils are well known to geologists by the papers 
of Say and of Conrad, but they still offer opportunity for much more 
investigation. The history of the Coastal plain is quite complex, there 
being many periods of more or less marked elevation and erosion end of 
depression and deposition, with the consequent unconformities. 
After the description of the various formations a brief resume is 
given of the periods of elevation, submergence, folding and erosion 
to which the rocks of Maryland have been subjected since the earliest 
times. Although of necessity written in a popular and sometimes ele- 
mentary manner, this paper will be welcomed by geologists and stu- 
dents as furnishing what we have not elsewhere, — a concise account of 
what is at present known concerning the geology of Maryland. 
Correlation Papers, Cretaceous. By Charles A. White, pp. 273, 
with 3 plates, and 7 figures in the text. (Bulletin No. 82, U. S. 
Geol. Survey, 1891. Price 20 cents.) Seven Cretaceous regions of 
North America are separately described in this memoir, namely, the 
Atlantic border, Gulf border, Texan, North Mexican, South Interior, 
North Interior, and Pacific border. In the classification of the forma- 
tions by their fossils they are assigned to eight horizons or divisions 
which are paleontologically distinct, namely, in ascending order, the 
Potomac, Comanche, Kootanie, Shasta, Dakota, Maritime or Interior 
(comprising the Colorado and Montana sub-horizons), Chico-Tejon, and 
Laramie. Of these the first four are classed together as Lower Creta- 
ceous, and the second four as Upper Cretaceous, the latter including 
both the Earlier and Later divisions of the series studied by Meek and 
Hayden on the upper Missouri. It is not assumed, however, that 
the division here made is precisely equivalent with that established in 
Europe; and especially it has not been found practicable to define so 
clearly as in Europe the lower and upper limits of the system. The 
synonymy of the formations, springing from independent studies by 
many geologists, is 6hown in a series of tables, which represent nine- 
