and the Mudlumps of the Mississippi. 367 



forming along each one of tlie passes, are liistoricall}^ known to 

 consist of mudlump-chains ; and in the absence of any phausi- 

 ble presumption to the contrary, as well as of any parallel 

 example in other rivers, it is reasonable to surmise, that not 

 oii!\ the shores of the present passes, but also the neck, at least 

 In 'ill Pointe a la Hache down, owes it formation and peculiar 



^^' have seen how rapidly and completely the joint action of 



■ OS and atmospheric agencies accomplish the degradation 

 licd lumps to the common level of the tide ; and where 

 ire of the materials is such as to yield readily to these 



■ vo influences, it would be unreasonable to look for 

 - of ancient lumps above that level. Such is the case, 

 ■i>^ mentioned, on Northeast Pass and its branches.* 



.' sandier nature of the mudlump mass on Southwest 

 iables it to resist much longer, so that some of the larger 

 "i-c elevated islands there seem destined to retain, more 

 permanently, their present form. For the sanie reason, 

 -. the Southwest Pass furnishes the one prominent ex- 



■ 'T the existence of an active and characteristic mudlump, 

 level marsh on the right of the channel, about five miles 



I'eunv the Head of the Passes, and seven above the mouth 

 ihght-house) ; distant 1^ miles from the river bank, and about 

 one mile fi'om the beach of West Bav. Double-headed Bayou, 

 or one of its channels, passes witlhin a few hundred yards 

 of this lump; which is so difficult of access that it has been 

 very rarely visited, though plainlv visible from the hurricane 

 deck of passing steamers, from which I have exammed it with 

 the telescope. 

 . According to Thomassy,t the pilot Ben. Morgan, who has 

 visited it, describes it as being " a regular truncated cone, 20 to 

 2o feet high and 300 in circumference, spouting at inter^^als 

 horn its summit masses of clayey and sandy mud, which over- 

 flows all around." . , 

 , .From the Pass, it now appears as a slightly irregular, conical 

 Wl, which, juddng from the extent to which it projects above 

 ^iie highest reeds, is about 18 to 20 feet high at most. On its 

 eastern side there is a second cone about half as high, with a very 

 regular slope not exceeding 30=, while that of the large one is 

 at least 45°. A whitish sheen which extends from the summit 

 of the larger cone toward the smaller one, I interpret as a 

 White salty efflorescence; but on the south slope of the smaller 



