AND THE SALT DETOSIT ON PETITE ANSE ISLAND. 13 



straticfraphical characters go, the identity is therefore complete. (See Miss. Hep., 

 1860, p. 6 and S.) 



The materials forming the highest portion of the central hills are nowher(> visible. 

 As we approach the outer slope, there is a change. Heavy greenish or bluish clays, 

 with ferruginous and calcareous concretions and obscure casts of shells and plants, 

 alternate with loamy materials and hardpans iindistinguishable from those at Cote 

 Blanche; wliile nearer the edge of the marsh thick strata of indurate silt or 

 hardpan, similar to those of stratum No. 6, at Port Hudson, arc alone visible. 

 Here, as at Cote Blanche, the stratification lines are seen roughly to conform to the 

 vmdulations of the surface ; so that the clay and hardpan strata are distinctly 

 inclined away from the highest portion of the island. 



It thus seems that the latter consists of a more or less horizontally stratified 

 nucleus of Drift materials, upon which the Port Hudson strata have been deposited 

 in a position roughly corresponding to the shape of the nucleus; there being, how- 

 ever, a marked increase of thickness toAvards the base of the slope, as might be 

 expected. The blue clay stratum with cypress stumps, also, is known to exist in 

 the beds of the bayous and under the sea-marsh, and has been found in cutting 

 ditches; although in some portions of the contiguous Cypres Mort swamp, a twenty 

 foot pole docs not find solid bottom.' 



Near Cypres Mort Point, south of Weeks' Island, an attempt to find salt water 

 was, during the war, made by Mr. John Gordy. He found at five feet a grayish 

 loam with very perfect crystals of gypsum, now in the possession of Dr. Dungan, 

 of Jeaneretts P. O. The thickness of this stratum was about two feet; then 

 came two and a half feet of water-bearing quicksand, then the "blue clay bottom." 

 The water was a weak brine, from which some salt was boiled; but it was abandoned 

 as unprofitable. The salt water was ])robably nothing more than Gulf water some- 

 what concentrated by evaporation ; the locality being a portion of the level Cypres 

 Mort Woods. 



A similar attempt was made about midway between Cute Blanche and Belle Isle, 

 on Salt Point, near Bayou Sale, by Mr. Carey. He bored some thirty odd feet, 

 when, striking "an oyster bank," he became discouraged and abandoned the well. 

 Unfortunately I have been unable to obtain the detailed record of this boring, 

 which, being in the level country, must have reached considerably below the sea- 

 level. The oyster-bed is precisely what, under similar circumstances, might have 

 been found on the coast of Mississippi Sound.^ 



' Tlicre arc seyeral small lakes or ponds on this island, to which Mv. Tliomassy ascribes the 

 character of "sunk craters." They do not, however, offer any unusual characteristics, requiring 

 subterraneous disturbances to produce them. The "round lakes" in the prairies, of which he speaks 

 in this connection, are universally attributed by the inhabitants to the action of cattle, which, when 

 frequenting water-holes in the dry season, not only deepen and enlarge them by pawing (hence " bull- 

 holes"), but also each time they drink carry off some of the tough prairie mud adhering to their feet; 

 and thus slowly but surely extend the basin into a pond. Under this point of view, their round form, 

 in a level country, is readily explained upon the basis of the law of probabilities. 



' Miss. Rep., ISGO, p. 154 aud ff. 



