308 x ANNUAL OF SCIENTIFIC DISCOVERY. 



inlets in the inclined plane which the bar presents on its inside, forces 

 the dissolved mud through their outlets on the outside of the bar, and 

 wherever these occur in the still water on either side of the channel, 

 an island or " mud lump " is formed around the orifice, varying in 

 height acccording to the force of pressure of the current, or the height 

 of the water in the river over that of the gulf. 



The cause, therefore, of the " mud lumps " is evident, and they 

 occur wherever a fissure is made in the upper strata of clay on the 

 outside of the bar, and at such points as the still water will allow the 

 mud forced out thereof to remain deposited. We hope that as the 

 cause of this phenomenon is now ascertained, some method of applying 

 it to the preservation of the channel will be found, by leading it to 

 form banks on either side or otherwise, and we congratulate Major 

 Beauregard upon his happy explanation of a phenomenon which has 

 been so greatly detrimental to the commercial interests of the'Missis- 

 sippi river. A r . 0. Picayune. 



NOTICE OF THE DISCOVERY OF A DEEP SEA BAXK, IN THE 

 EXAMINATION OF THE GULF STREAM. 



The following communication was presented at the last meeting of 

 the American Association, by Prof. A. D. Bache. The Gulf Stream 

 has been explored in connection with the Coast Survey by running 

 sections perpendicularly across it, at different points in its course, and 

 exploring the temperature, and as far as practicable, other phenomena 

 of the stream at stations on those sections ; and from the surface to 

 depths of six, and in some cases of 1200 fathoms. The stations being 

 selected at greater or less distances, according to the less or more rap- 

 id changes occurring in that portion of the stream which they were 

 intended to explore. In the explanation made in June last, the 

 hydrographic party of Lieut. Commander Craven was instructed to 

 explore the stream on four sections, beginning with one from Cape 

 Canaveral, Florida, perpendicular to the direction of the stream ; next 

 taking up one across it, from St. Augustine ; next from St Simons, 

 Georgia ; and last from Charleston, S. C. 



That of Lieut. Com. Maffit was to run over the same section from 

 Charleston, and then take up others in succession, further north. The 

 section from Charleston was explored by Lieut. Com. Maffit's party 

 between the 2d and the llth of June, and soundings were kept en- 

 tirely across the stream at depths of less than 600 fathoms, the bottom 

 being brought up. The longitude named was 7 7 deg. 1 2 rnin. 



On the llth of June, Lieut. Commander Craven, having crossed the 

 Gulf Stream without finding bottom at 1000 fathoms, came upon a 

 deep sand bank at a depth of 469 fathoms, in lat. 28 deg. 24 min. N. ; 

 long. 79 deg. 05 min. W. This bank was again struck on the section 

 north of this one at similar depths, bottom being brought up, and traced 

 thus to a position comparing with the Charleston section, where it had 

 been struck by the other party, and bottom brought up from the depth 

 of 300 fathoms, in lat. 31 deg. 37 min., and lono;. 78 deg. 33 min., on 



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the 7th of June. 



