applicable to the Theory (if the Earth. 101 



B. Of Incrustations of different Kinds, and particitlarlij the 

 incr listed Sliells found in different Parts ofNeiu Holland. 



One of the particular advantages of extensive navioations 

 and long voyages is, that the theatre of observation is so 

 much varied, and objects so multiplied, that nothing is 

 often wanting but a sound judgment to make the most 

 difficult comparisons, and to deduce from them important 

 consequences. What man, for example, can see, with 

 indifference, around him that succession of beautiful in- 

 crustations so frequent on the shores of Kangaroo Island, 

 on those of the Archipelago, of St. Peter and St. Francis, 

 and on the shores of the immense Bay of Seals ? In one 

 place whole trunks of shrubs are entirely covered with a 

 mixed stratum of freestone and calcareous matter, and in 

 others are accumulated branches of trees, roots, shells, 

 zoophites, the bones of animals, and excrements of qua- 

 drupeds, concealed under the same covering. ^' One 

 might be tempted to believe," said the unfortunate Riciie, 

 "that a new Perseus carried the head of Medusa over these 

 distant coasts. '' 



On the sight of so many striking singularities, how can 

 we forbear inquiring into the cause, and how is it possible 

 that it should not be discovered in the particular nature of 

 the sand on these shores? The numerous shells, indeed, 

 produced in these seas being continually rolled by the 

 action of the waves on the neighbouring shore, are thus 

 reduced to very small fragments, which being afterwards 

 mixed with thequartzy sand, soon form with it a calcareous 

 cement of a superior quality. In carefullv examining its 

 materials one might be tempted to believe that Dr. Hicgins, 

 in his ingenious Essay on Calcareous Cements, had sroleu 

 the secret of nature. The proportions, indeed, which he 

 indicates as susceptible of forming the most solid combina- 

 tion, that is, one part of lime and seven of quartzy sand, 

 are those which nature seems to have adopted for her ce- 

 ment. But whatever this composition may be, it is the 

 only agent of those remarkal)le incrustations of which I 

 have spoken. On the shore it soon incrusts every body 

 thrown upon it; testacea, zoophites, galets, are all agglu- 

 tinated by it. The observer sees, as we sav, formed before 

 his eyes, thebreches and puddingstones of vvliich the neigh- 

 bouring rocks are composed. 'I'ransported by the winds, 

 this active matter deposits itself on the nearest shruijs. At 

 first it is only a light kind of dust, which soon becomes 

 solid around the stem whicli it embraces. From that mo- 



Vol. 22. No. 86. July 1805. L meat 



