STTJDLAND. 



437 



nels. » The spot where they so thickly occur is represented 

 by the letter A, at the extremity of the cliff in the following 

 section (fig. 55), and the continuation of which is seen in fig. 

 56. 



From the Red Rock to the Preventive Station. 

 55 



Red Rock. — Yellow sandstone rock. 2, Red sand rock. 3, Red clay and sand. 



4, Indigo clay, with lignite, 18 feet. 5, Yellow sands and clays. 



1, Sand hills. 2, Ravine. 3, Clay and yellow sand. 4, Chalk Downs. 



5, Yellow sand and sandstone. 6, Preventive house. 



The bearing indicated by the arrow is S. W. by W. 



1 The cylindrical tubes of the Isle of Wight are capable of being separated 

 from the green sand in which they occur, but the tubes of Studland can- 

 not be separated ; they are evidently portions of the sand-rock itself, where- 

 as the Isle of Wight tubes appear to be casts of some vegetable body. — 

 Such also appeare to be the case with certain calcareous tubes in the Main 

 Island of the Bermudas. These, however, occur in beds of blown sand, 

 and owe their calcareous incrustation to the infiltration of water, bringing 

 down calcareous matter with it. " The calcareous tubes," says Lieut. Nel- 

 son, " are very generally found throughout the islands, apparently aggre- 

 gated around grass or small roots, as nuclei, which have subsequently de- 

 cayed. They have almost always an earthy matter running down the axis. 

 Beds, nay strata, of these tubular deposits, may be found in various parts, 

 as in the neighbourhood of Tobacco Bay, near St. George's, and in the 

 bank a little to the westward of Harris' Bay, where the cliffs commence ; 

 though nowhere to such an extent as at Ireland Island, between Bombay 

 and the south-west point, where the stratum is about four feet thick, and 

 corresponds to a similar formation on Skinner's or Tate's Island. 



" The cliffs to the westward of Elbow Bay are curiously perforated to a 

 great extent by similar tubular holes ; but they are there detached from each 

 other, and are generally vertical and much larger." — On the Geology of the 

 Bermudas ; by R. J. Nelson, Esq. Lieut. R.E. in G. T. v. 101. the lat- 

 ter example best suits the case of the Studland tubes. 



Vol. III.— No. 33 n. s. 3 a 



