28 W. M. Fontaine—Mesozoic Strata of Virginia. 
South of the Nottaway, no traces of the Mesozoic have been seen. — 
This belt may be called the Petersburg Belt. A seventh belt — 
similar to the last is found nearly in the prolongation of it ina — 
direction due north. This begins a little south of Fredericks- — 
burg and continues along the eastern border of the Azoic, ina — 
northerly direction. Its western margin passes several miles — 
west of Alexandria. As it passes out of the State it bends to — 
the northeast, so as still to hug the eastern margin of the Azoic. — 
So far as I have traced it, it extends at least as far north as — 
Baltimore. This may be called the Fredericksburg Belt. Both — 
to meet at an acute angle. e statement made in the revised q 
edition of Dana’s Manual gives the usually accepted opinion. — 
This statement is that the Richmond area begins on the Po- — 
tracts in the Azoic which have approximately the dieses of © 
the strike of the Azoic strata. The a 
areas is fixed by the previous establishment of lines of weak- — 
ness, by the processes producing the metamorphism of the — 
