1879. | The Mesozoic Sandstone of the Atlantic Slope. 285 
Rothliegendes of the German scale.” The thickness calculated 
by him for Prof. Rogers’ section below Yardleyville is 51,500 
feet, or nine and three-quarters miles, on the assumption that 
the bedding is normal, but this is regarded as delusive; and 
in a subsequent paper, by the same author, on “ Some Meso- 
zoic Ores” (Am. Phil. Soc. Proc., April 20, 1877), the wave- 
strewing hypothesis, by means of which Prof. Rogers sought 
to explain the inclined bedding is rejected as insufficient to ac- 
count for all the phenomena. 
Mr. Heinricks paper is rich in facts, and is as remarkable for 
the absence of speculations as it is for the clear and logical stand- 
point from which he views the whole subject. Like Prof. Fontaine, 
he commences by describing the divisions of the formation into 
belts, but whereas Mr. Heinrich groups all the known exhibitions 
of Mesozoic, in Virginia, into four belts, Prof. Fontaine disposes 
of them in six belts. This latter arrangement does not seem to 
be necessary by reason of the small gaps between the various 
members of Heinrich’s belts, and presents to the student not on. 
the ground, manifestly greater inconveniences. 
It is evident that even Heinrich’s number of divisions i is arbi- 
trary, since a prolongation of the “Eastern” belt crosses the 
“ Middle Eastern” at Taylorsville and joins the “ Middle Western 
at Mount Vernon,” but these separate ranges and the lines indi- 
cating them on his map, greatly assist the understanding of his 
minute details. His belts here follow. 
A Eastern—Includes (1) the ra AS and (2) the 
scattered masses of Mesozoic in Greenville and Brunswick 
counties, west of Hicksford and east of Ladhadeniies 
B Middle Eastern.—(1) rif asa deposits, (2) Springfield 
deposits, (3) Richmond depos 
C Middle Western—(1) Aquia aie te) Farmville deposits, 
from Mount Vernon to Fredericks 
D Western.—(1) Potomac deposits, ramping from the Poromag 
river near Point of Rocks to the Wilderness, (2) Barbo 
ville deposits, (3) James River deposits (near ‘Scottsville), G) 
Danville deposits, (5) Dan River deposits, on and south o 
the N. Carolina line. 
Prof. Fontaine calls D1 his “New ¥ersey” belt, D 3 his 
Buckingham belt, D 4 the Pittsylvania belt, C 2 (or a part of them) 
the Prince Edward belt, B 3 and a part of A 1 the Richmond 
belt, the southern portion of A 1 the Petersburg belt, which Prot. 
Fontaine describes as overlapping the Hanover area (č. e., the 
