EL, W. Hilgard—Geology of Lower Louisiana. 83 
There can therefore be no doubt that the salt deposit is older 
than the Orange Sand, which here as at Weeks’s Island, forms 
the nucleus of the mass on whose outer slopes, as well as its 
igher points, the strata of the Port Hudson profile reappear 
characteristically ; with calcareous nodules, fresh water shells 
and aquatic plants identical with living species. Not only is 
the reference level of the cypress stump stratum the same as 
elsewhere, but the green clay band, No. 4 of the Port Hudson 
profile, is also there. 
The stratigraphical disposition of these deposits is quite re- 
markable, They conform not to the strata, but measurably 
to the outline of. the Orange Sand nucleus, roughly following 
its slopes and curvatures. At first sight therefore it seems as 
ough a local upheaval had taken place, and hence arose, 
probably, the reports attributing a volcanic origin to these ele- 
vations, whose isolated position in the level coast region would 
naturally give rise to speculation as to their mode of formation. 
Indeed the extent to which these strata are sometimes seen to 
dip, rather staggers the observer; but the upheaval hypothesis 
deposition on inclined surfaces. But when we see an appar- 
ently undisturbed clay-stratum moving down hill like a gla- 
Cler, sO as to overflow a deposit of loose stones, we need not go 
_ far to find the cause of extensive dislocation and subsidence. 
Belle Isle and Miller’s Island. 
ture of these exterior islands, tend to confirm the probable sup- 
_ Massy places in the same category the Grand Coteau des Ope- 
usas and the Avoyelles prairie. Le ae 
Age of the Salt Deposit. — 3 oe 
The Orange Sand strata so rarely approach the coast, that a 
the deposits underlying them in the Coast region have sc 
