islands are related to the head lands and the shore.  Here is a general fact, from the simple inspection of which we must conclude one of two things; either that those rocks and smaller islands, which we have termed parasitical, are in a state of progression, by which in time they will be joined to the main land, and form one continent; or that they are in a state of degradation, by which in time they will be made to disappear.  There is no other supposition to be made; and, of that alternative, there is no room to hesitate a moment which to choose.  This is not a matter of mere probability, it is the subject of physical demonstration.  Should we find an old manuscript in a similar condition, we could not conclude with more certainty, that the deficient or intervening places had been destroyed, than we here conclude that the part which is now wanting, between the two remaining portions of the same rock or strata, had once connected those two portions, and had been destroyed by the operation of those causes which are every day employed in still increasing the breach.

Though over all the world, where the shore is washed bare by the sea, examples are to be found which require but to be seen to give compleat conviction, it is not in every place that the eye of a naturalist has been employed in taking this view of the coast; nor is it upon every occasion that enlightened philosophers of this kind have given their thoughts upon the subject.  M. de Spallanzani has given us the following observations with regard to the coast of Italy[15].

[Footnote 15:  Observations sur la Physique, etc.  Juliet 1786.]

“Autant l’interieur du petit bourg de Porto-venere et les rochers qui l’environnent sont a l’abri des tempetes, autant les parties exterieures sont exposees aux coups de mer les plus violens, lorsqu’elles sont en proie au deux terribles vents d’Afrique et a celui du sud-est.  Ce dernier en particulier souleve les flots avec tant de violence et a une telle hauteur contre les ecueils qui servent de defense a ce petit terrain, que la mer semble menacer de l’engloutir.  J’ai ete le temoin d’un de ces orages, et quoique je fusse a l’abri de tout danger, je ne pourroit vous representer l’horreur que me fit eprouver ce spectacle.  J’ai voulu prendre avec exactitude la hauteur moyenne de l’elevation des flots dans les plus violens coups de vent; et quand je vous en parlerai vous serez etonne de leur force et de l’etendue de leurs effets.  Les rochers qui sont a la partie meridionale de Porto-venere se rongent et se detruisent peu-a-peu de meme que les trois isles voisines Tiro, le petit Tiro, et Palmarin.  On le remarque surtout dans cette dernier:  les bords voisins de la terre ont une pente douce; ils sont couverts d’arbres et de plantes, tandis que la partie opposee est deserte et inaccessible couverte de precipices, de ruines et d’horreurs; les autres parties du rivage sont renfermees par la riviere du ponent et par celle