OF SOUNDINGS. 7 



By levigation a great variety of silicious Infusoria was obtained. The most 

 interesting of the species were Rhaphoneis rhombus, and several undetermined 

 species of the same genus, fig. 61 to 65, Triceratium favus Ehr., fig. 54, Cos- 

 cinodiscus radiatus, C. excentricus, C. hneatus, Actinoptychus senarius, frag- 

 ments of Actinocych, Galhonella sulcata, Navicula sigma, fig. 52, a new species 

 of Denticella ? bearing two long spines on the middle portions of the terminal 

 surfaces, see fig. 57 ; Dictyocha fibula, and D. speculum, fig. 60 ; sponge spicules, 

 fig. 58, were also found. 



H, No. 17, 20 fathoms ; latitude 38° 29' 56"; longitude 74° 38' 04". 



A clean quartzose sand, coarser than the last, white and yellow, with black 

 specks — no Polythalamia detected. By levigation a few Infusoria were found, 

 among which were Coscinodiscus radiatus, C excentricus, Galhonella sulcata, 

 Stauroptera aspera, Striatella arcuata, Pennularia didyma, P. peregrina, Tri- 

 ceratium favus, fig. 54, Navicula lyra, Navicula sigma, fig. 52, and Dictyocha 

 speculum, fig. 60. Soft parts of Polythalamia, retaining the form of the cells, 

 were also noticed. 



H, No. 67, 50 fathoms ; lat. 38° 09' 25"; long. 74° 04' 05". 



A clean grayish sand, containing a few minute shells of Globigerina and Rot- 

 alina. The infusorial forms obtained by levigation were not abundant ; among 

 them were Coscinodiscus oculus-iridis, C excentricus, Actinoptychus senarius, 

 Galhonella sulcata, and Triceratium alternans, figs. 55 and 56. 



H, No. 1, 90 fathoms ; lat. 38° 04' 40"; long. 73° 56' 47". 



A rather coarse gray sand, with some mud, and containing a vast number of 

 Polythalamia, particularly of Globigerina, many thousands of which must exist 

 in every cubic inch of the sea bottom at this locality. Marginulina Bacheii, fig. 

 2 to 6 ; Globulina universa, fig. 1 ; Robulina D'Orbignii, figs. 9, 10 ; aod Rotalina 

 Ehrenbergii, fig. 11 to 13, are also common. 



By levigation a few specimens of Coscinodiscus radiatus, Galhonella sulcata, 

 and Triceratium alternans, figs. 55, 56, were obtained, with great numbers of 

 the minute globular bodies, which 1 have supposed might be the ovae of Poly- 

 thalamia ; they occur not only singly but in strings and bunches, as represented 

 in fig. 49. 



In water these bodies are easily seen, but when mounted in balsam they can 

 scarcely be perceived, their cavity becoming nearly filled with balsam, and the 

 thin shell almost vanishing from sight. 



GENERAL RESULTS OF THE ABOVE EXAMINATIONS. 



1st. The most remarkable fact determined by the examination of the above 

 mentioned soundings is, that in all the deep soundings, from that of 51 fathoms 

 S. E. of Montauk point, to that of 90 fathoms S. E. of Cape Henlopen, there is 



