Page:Memoirs of the Geological Survey of Great Britain, Volume 1.djvu/355

342 calamus. Some, such as Primula farinosa, Lysimachia thyrsiflora, and Convallaria verticillata, seem to indicate a more northern point of derivation of this Germanic flora than that from whence the main part of its assemblage of plants came. It is remarkable that certain species of this flora, which flourish best on limestone, such as 'Scabiosa columbaria, Sison amomum, Campanula glomerata, and others, are not found in the limestone districts of Ireland, and in like manner certain species, which everywhere, when found, delight in sand, as Ajuga chamæpitys (more properly a member of III. than of V.), are also wanting on such Irish localities as are best adapted for them.

The fauna which accompanies this flora presents the same peculiarities, and diminishes towards the north and west. This is very observable, both among the native vertebrate and invertebrate animals. Thus, among quadrupeds, the mole, the squirrel, the dormouse, the polecat, and the hare of England (Lepus timidus), are confined to the English side of St. George's Channel, not to mention smaller quadrupeds. So it is also with the birds of short flight; so most remarkably, no less than half the species being deficient, with the reptiles; so also with the insects, and the pulmoniferous mollusca. Among the latter animals are several species, which mark the fauna of the Germanic type as distinct from those of the more southern provinces. Such are Helix scarburgensis and excavata, Clausilia dubia, and Pupa alpestris.

In the preceding summary view of the regions or provinces into which our flora and fauna may be divided, I have gone into no further detail than is necessary for the display of their principal and characteristic features, such as may be grasped by persons not familiar with the abundant details and materiai amassed in our British faunas and floras, which are more complete probably than those of any other country. It is this very completeness which enables us to pursue such inquiries as the present, which, indeed, could not be entered upon with advantage unless there were abundant data gathered together. The essays of Mr. H. C. Watson may be cited as among the most remarkable, and to them I must refer geologists who would wish to learn more respecting our indigenous flora, than it is here necessary to state.

It cannot be expected that in this stage of the inquiry all exceptional cases in our flora and fauna can be explained. There are several extremely difficult of explanation, but they are neither so numerous nor of sufficient importance to afiect the general argument, and may safely be put aside for the present, in the certainty that the progress of research will ere long make clear the most doubtful.

To determine the how and when of these peculiarities, on the