Geology^ and Climate of the Island of Madeira. 9 



Voluta, Cypraea, most of the apparently extinct shells, with 

 some corallines and zoophytic remains. The conclusions of 

 Mr Bowditch (at page 68, " Excursions," &;c.), with others 

 founded on them, based on the idea of " a vast bed of transi- 

 tion limestone of a depth of 700 feet," therefore, fall to the 

 ground.* 



From the preceding notes, although I have not entered into 

 any details, it will bo readily perceived that the island presents 

 a tine field for geological study. Even from the few facts that 

 have been referred to, many interesting conclusions might be 

 drawn. 



It appears probable, from the similarity of their volcanic 

 rocks, that there exists between the Madeira and the Azores, 

 the Canaries, and other islands in that part of the Atlantic, 

 an intimate geological connection. In all, there abound tho 

 same basalts and conglomerates, and layers of scoriae. In Te- 

 neriffe and St Michael, and other islands where the volcanic 

 action is still in activity, these formations are covered by many 

 series of more recent deposits, the ancient and modern lavas 

 being distinguished from one another. Tho volcanic action 

 having been long extinct in Madeira, there are found none of 

 these modern deposits, but its rocks are tho same with the 

 older series in the other islands. This similarity has led some 

 geologists to revive the speculation concerning a former conti- 

 nent or large island existing in these parts ; the Atlantis per- 

 haps of the ancients. In addition to what has been urged in 

 this matter by Bory St Vincent and previous writers, Sr. Mon- 

 sinho, in the memoir already quoted, supports the idea, and 

 considers Madeira as a portion of a vast region which has been 

 broken up and in a great part swallowed by the ocean. If this 

 fancy were not by many other proofs shewn to be groundless, 

 a very slight consideration of the geological appearances of the 



* In the adjoining island of Porto Santo, there is a recent tertiary lime- 

 stone, also abounding in fossil shells. I did not visit this ; but at the lime- 

 kiln near Funchal, which is supplied from it, I collected many specimens. 

 I have not yet had ray specimens determined. One or two appear tho same 

 as species found at St Vincent's. Many of them are probably different spe- 

 cies from any that have been elsewhere discovered. 



