the species by the smell, and more particularly 

 by chewing- the woody fibres. Two natives, to 

 whom the same wood is given to chew, pro- 

 nounce, and often without hesitation, the same 

 name. We could avail ourselves but little of 

 the sagacity of our guides, for how could we 

 procure leaves, flowers, and fruits growing on 

 trunks, the branches of which commence at 

 fifty or sixty feet high? We were struck at 

 finding in this hollow the bark of trees, and 

 even the soil, covered with moss and lichens *. 

 The cryptogam ous plants are here as common 

 as in the countries of the North. Their growth 

 is favored by the moisture of the air, and the 

 absence of the direct rays of the sun. Never- 

 theless the temperature is generally at 25° in 

 the day, and 19° at night. 



The rocks which bound the crevice are per- 

 pendicular like walls, and are of the same cal- 

 careous formation which we observed the whole 

 way from Punta Delgada. It is here a blackish 

 gray, of compact fracture, tending sometimes 

 toward the sandy fracture, and crossed by small 

 veins of white carbonated lime. In these cha- 

 racteristic marks we thought we discovered the 

 Alpine limestone of Switzerland and the Tyrol, 



* Real musci frondosi. We also found, beside a small 

 boletus stipitatus, of a snow white colour, the boletus igni- 

 arius, and the lycoperdon stellatum of Europe. I had found 

 this last only in very dry places in Germany and Poland. 



