AND TUE SALT DEPOSIT ON PETITE ANSE ISLAND. 7 



to be largely represented. There were some upright fragments, but no stumps in 

 place. 



There is a striking difference in the state of preservation of this drift-wood 

 imbedded in sand, as compared with the well-preserved cypress stumps in the clay 

 below. The wood here is in a soft, spongy condition, so that when soaked with 

 water it is visibly flattened by its own Aveight when lying on the ground. A stroke 

 of the hatchet will thus sever a trunk twenty inches or more in diameter; but when 

 exposed to continuous sunshine in this water-logged condition, the mass not only 

 loses its water, but itself contracts into hard shining lignite of conchoidal fracture, 

 exhibiting to the eye scarcely a trace of the original structure; a trunk six or eight 

 inches in diameter being represented by a contorted band of coal, not over half an 

 inch thick. While the projecting ei.d of a trunk is thus transformed, the portion 

 remaining imbedded retains its original condition; suggesting forcibly the enormous 

 amount of vegetation required to form a coal stratum out of drift-wood, or spongy 

 C'alamites resembling it ; and how difficult it must always be to identify the vege- 

 table structure of the product of such a process. It shows, moreover, how little 

 weight can attach to the state of preservation of fossil wood in determining the 

 relative age of deposits ; a point of special importance in connection with the 

 geology of the late alluvial and littoral formations. 



As for the green clay stratum No. 4, it varies but little either in thickness or 

 composition. It forms, therefore, a convenient level of reference, since it seems to be 

 as consistently represented even at distant points, as the lower stump stratum, and 

 fossils are most aliundant immediately beneath it, where they occur at all. 



The " hardpan" stratum. No. 5, also exhibits here the two main facies which I 

 have elsewhere observed, viz., either of uniformly fine, semi-indurate silt or hardpan, 

 light yellowish-gray, mottled with irregular ochreous spots; or else, of deposits 

 greatly resembling, at first sight, many of those of the Stratified Drift, but in most 

 cases distinguishable from the latter both by position and composition. So far as 

 I have seen, it is void of any trace of fossils ; but for this, and for the interposition 

 of the clay stratum No. 4, it would often be undistinguishable from the hardpans 

 of No. 3. By exposure to the atmosphere, it becomes eroded into curious pinnacled 

 forms, representing in an instructive manner the gradual formation of valleys of 

 denudation, as in relief maps. 



It is interesting to compare the present condition of the blufi", as above described, 

 with the descriptions given at previous periods by three other observers, viz. : Bar- 

 tram, in 1777; Dr. Carpenter, in 1838; and Sir Chas. LycU, in 184(5. 



Bartram, without giving a detailed description of the upper strata, alludes to the 

 variety of material and colors they present. He mentions more specially the stump 

 stratum, No. 1, the material of which he states to be "of the same black mud or 

 rich soil" as that of existing cypress swamps; and that the trunks, limbs, etc., of 

 the trees lie in all directions about the stumps. This description do(^s not api)ly at 

 present; no trunks or branches (save minute twigs mingled with the leaf mould) are 

 now visible around the stumps; nor is their soil stratum at all comparable to 

 swamp muck. 



Dr. Carpenter examined a section several hundred feet to the eastward of tliat 



