8 EXCURSIONS IN MADEIRA 



this transition limestone, and proved to be 564 feet above its 

 lowest visible bed (no other rock alternating with, or appearing 

 between it), or about 600 feet above the level of the sea*" Over 

 the thin layer of vegetable mould which covered the limestone, 

 were scattered large rounded blocks of a dark-coloured, compact 

 Uwsalt, glistening with crystals of horneblende, generally covered 

 with a moss (Iti/pnmn intricatum) on the part nearest the soil, 

 and with lichens (patellaria ventosa and urceolarla occellata) on 

 the upper surface''. 



Ascending the hill which appears in the drawing, to the eastern 



' Barometer 741.50, thermometer 20, thermometer detached 19a cent. 



'' I found three other lichens, which were not sufficiently advanced for me to 

 determine ; and a fourth, which I can only refer to the idiothalames heterogenes of 

 Acharius, having been unable to afford any works on cryptogamia, and my memoranda 

 being too limited to decide on species, or even genera in all cases. I intend, at present, 

 to send home drawings of the new genera and species of the zoology and botany of 

 the parts of Africa I may be enabled to visit ; and I hope to persevere in this plan 

 throughout my travel, even should it be extended to some years, by a reasonable 

 support on the part of the government. It takes away very much from the usefulness 

 of a travel, when it is attempted to save the trouble of making drawings, by substi- 

 tuting for that concise description of the object, which will always suffice with an 

 accurate figure, a verbose detail of tiresome minutiee, wholly uninteresting, and fre- 

 quently unintelligible, without the aid of the pencil. The only probable difficulty is, 

 that no publisher will undertake the expense of having all these figures engraved, and 

 that they may thus be lost to the naturalist and others, who would feel an interest in 

 referring to them as illustrations of the text. Contemplating this probability, I deter- 

 mined to obviate it in some degree, by regularly transmitting a set of these drawings 

 to Sir H. Davy, to deposit wherever he considers they may be most readily consulted 

 by the naturalists of my own country, who will always find them numbered so as to 

 correspond with the references in the text of my travels. I shall also transmit a 

 duplicate set of these drawings to Baron Cuvier, to be deposited for the same purpose 

 in the library of the French Institute. The two sets of 107 figures (several of which 

 are coloured) referred to in this first part, are forwarded with the manuscript. 



Mrs. Bowdich, having' reached England before the printing: of t'lc manuscript, has withdrawn the 

 above-mentioned figures, and published the greater number of tliem in the work itself. — Ed. 



