AND PORTO SANTO. 61 



been separated from the shore by a similar volcanic effort, (subse- 

 quent to that grand burst and ejection which covered the face of 

 the primitive island) aided by the long-continued abrading action 

 of the sea. I here found the cheirantkus mutabilis ; I understand 

 it is constantly purple, (in various shades) when growing by the 

 sea-shore, and that its variations of colour depend, not on situation 

 alone, but on soil. I must also describe a plant, which, from 

 the novelty of its fructification, I cannot refer to any family ; 

 its leaves first induced me to suppose that it belonged to the 

 sempervivce, but no other character accorded, and I must leave 

 its decision to a future traveller, who may procure a better speci- 

 men, reserving to myself the pleasure of naming it after my friend 

 the Provost of Eton*^. 



The first excursion I made to the eastward, was to the Brazen 

 Head or Garajao. Descending the hiU to the ravine crowned by 

 the Fort, we find basalt reposing on a shallow deposit looking like 

 a harsh, indurated, ferrugineous mud ; beneath which is the red 

 tufa, so heavily charged with basaltic nodules as to resemble a con- 

 glomerate. As we pass over the bridge, we observe that the 

 streams of basalt have flowed about S.S.E. from the interior of the 

 island, and ascending the eastern side of the ravine, we find the 

 mud-Hke deposit mixed with, or between the basalt, which forms 

 prolonged, inosculated, shallow vaults above it. The red tufa 

 beneath has evidently been deposited in fine layers, and where it 

 has partially slipped, or given way from the superincumbent weight 

 of the basalt afterwards flowing over it, it has led to correspondent 

 inflections and depressions in the strata of basalt above it. I can- 



•^ Genus. Goodallia. Radix fusiformis. Folia succulenta; juniora a medio in 

 modum monocotyledonum nascentes. Caulis herbaceus, scapiformis. Capsula pla- 

 centa centrale, 4 valvis, in medio transverse patens, et postquam matura cum placenta 

 et valvis exiliens : plurima semina, niinuta, rotunda, atra, in parte inferiore capsulae 

 persistentia. Sp. 1. Foliis trilobatis. Sp. 2. Foliis lineanbus. 



