12 W.S. Sullivant and T. G.Wormley on Nobert’s Test Plate. 
cotton with so little labor, are in the transition stage to the pine | 
barrens, and cannot be expected to retain their fertility for any : 
great length of time, unless lime is restored to them by the cul: — 
tivator. ‘The heavily-timbered Hammocks require @ greater out- | 
lay to bring them under cultivation; but they constitute the — 
most valuable and enduring lands in this section of the State. | 
Unfortunately they embrace but a comparatively limited area, — 
when contrasted with the space occupied by the pine lands. — 
The outlines of the Hammocks, as indicated by the dense growth — 
of gigantic evergreens, is singularly and sharply defined, either © 
dotting or intersecting the desolate pine-barrens; sometimes — 
forming narrow sinuous verdant bands extending ten or fifteen 
miles, which, at a distance, remind one of extensive swamps, Or — 
the bottom lands bordering a stream. . 
Columbia, S. C., June, 1869. 
Art. IL.—On Nobert’s Test Plate and the Strice of Diatoms; by 
W.S. SULLIVANT and T. -G. WorM.eEy. 
? 
amination of Nobert’s Test Plates, was unable to resolve any lines 
closer than the ;;,4;5 of an inch. In Prof. Carpenter's work 
rom the foregoing it appears that actual experiment fixes 
h: this does 
which seems theoretically possible gone , 
ished.” ee 
~ On the other hand there are authorities who assert that | 
much closer than the ;;,}55 of an inch are resolvable, P 
