196 Holmes' s Notes on the Geology of Charleston. 



the superficial vegetable deposit in the manner already described. 

 The large trees having their tap-roots below the loam, were first 



killed, and many of them being exposed for a long time as erect 



dead trunks, were broken off by gales, which left the stumps in 

 the position in which we now find them. The mud below be- 

 coming very soft, permitted these to sink into it and become im- 

 bedded, leaving the peaty loam above them in the possession of 



small cedars, the former undergrowth of the swamp. 



May not many of the instances to be met with along the sea- 

 board, and which have been cited by geologists as cases of subsi- 

 dence, be referred to the operation of similar causes? 



Off the beach at Coles Island, about one hundred yards from 

 shore, are several stumps of oak trees, erect, surrounded by beds 

 of oysters (O. virginiana) and only exposed at low water. Among 

 them is one trunk of a live oak, (Quercus virens,) about eight 

 feet high, over the top of which the tide at its highest does not rise, 

 presenting a most singular, but interesting sight, when the heavy 

 surf at high water is rolling around it. On a calm day, during 

 one of my visits to this spot, I moored my boat to it whilst ma- 

 king observations in the survey of the inlet. 



Next in order as we descend below the Post-pliocene, under 

 the city of Charleston, is the Eocene, or lower Tertiary ; the first 

 stratum being an olive-colored peaty substance, resting upon an- 

 other of sand, that separates it from the great marl-bed below. 

 This stratum of sand contains a quantity of water, which, in the 

 boring of the Artesian well, rose in the tubes to within six feet 

 of the surface, and greatly obstructed the progress of the auger 

 by filling it with quicksand. 



Imbedded in the peaty substance before mentioned, are num- 

 bers of rolled and water- worn rocks of all sizes, from a few inches 

 to a foot in diameter; a fresh fracture in any of which discloses 

 the same forms of fossils as are seen in the great marl-bed below, 

 of which, no doubt, these are fragments, broken off by the action 

 of the sea, and rolled into bowlder-like masses ; their nature 

 changed by some chemical process, whereby nearly all the lime 

 has been extracted, and the casts of the shells are left preserved 

 ill a silicious rock, emitting when broken a foetid odor. The 

 causes which produced the separation of these fragments, and the 

 subsequent deposit of them in a distinct stratum one foot thick, 

 are yet undetermined. The fragments are much larger where 

 they crop out on the surface, ten miles north of the city, than 

 they are in the part of the basin immediately beneath it. 



These strata, including the first ten feet of the underlying marl, 

 may be properly called the " Zeuglodoir' or " Basilosauriis" bed 

 of the "Charleston basin, " which Professor Agassiz has pronoun- 

 ced u the richest cemetery of animal remains that he had ever 



