350 Dr James Macaulay on the Physical Geography, 



several feet in thickness, are well marked, denoting successive 

 volcanic showers of different materials. Some of the layers 

 consist of white lapilli of pumice, which have very small specific 

 gravity, and float on the surface of water. These layers of 

 light pumice alternate with various beds of heavy dark tuffs 

 and sand. This disposition of the layers proves that they have 

 been deposited on the land and not at the bottom of the sea, 

 where they would have taken their place in relation to their 

 specific gravity. In several places the beds dip down under 

 the present level of the ocean, proving, that, since their depo- 

 sition, there have been depressions in the surface of the land in 

 these parts. 



II. Formations not Volcanic. 



Along the same soa-cliffs, in the vicinity of Funchal, are 

 seen beds or strata of matter, not of volcanic origin, lying be- 

 neath some of the basalt and other pyrogenous products. In 

 these beds are found the roots of plants encrusted with mineral 

 matter. From the number of such vegetable remains, it is 

 probable that the chief materials of this earthy deposit consist 

 of the old vegetable soil which covered the island. At the 

 eastern extremity of the island there exists a remarkable for- 

 mation, which has been thought analogous to these earthy 

 beds, but to contain vegetable remains in far greater abun- 

 dance. It is termed generally the Fossil Forest of Cani9al, 

 which is the name of the parish in which it occurs. Believing 

 the general opinion regarding its nature to be erroneous, I will 

 refer at greater length to this formation. 



Fossil Formation of Cani(;al. — The Point St Louren9o, which 

 forms the eastern extremity of the island, extends about three 

 miles into the sea with an inconsiderable breadth. The land, 

 immediately before where it becomes contracted to form the 

 Point, and nearly to the Cape at the extremity, consists of 

 beds of basalt and of conglomerates, as I have described most 

 of the high grounds to be composed. In sailing along the south 

 coast from the town of Machico, from which visitors generally 

 set out to visit the fossil bed, the structure of the formations 

 on the lofty coast are finely seen ; different layers of conglome- 

 rates, globular and scoriaceous, traversed every where by veins 



