500 REVIEWS THE STORY OF A BOULDER. 



from the shores of the Mediterranean gorging itself on sheep and lambs among 

 the wolds of England,* just as we often see 



" A double cherry seeming parted, 

 But yet an union in partition ;" 



or as we hear of a sheep with five legs, and a kid with two heads. But these 

 exceptions, from their comparative rarity, only make the laws more evident. 

 When, therefore, we find, in various parts of our country, beds of shells in such a 

 state of preservation as to lead us to believe that the animals must have lived and 

 died where their remains are now to be seen, we justly infer that the districts 

 where they occur must at one period have been submerged. If the shells belong 

 to fresh-water species, it is plain that they occur on the site of an old lake. If 

 they are marine, we conclude that the localities where they are found — no matter 

 how iiigh above the sea —must formerly have stood greatly lower, so as to form 

 the ocean bed. To proceed one step further. If the shells are of a southern 

 type, that is, if they belong to speciesf which are known to exist only in warmer 

 seas than our own, we pronounce that at a former period the latitudes of Great 

 Britain must have enjoyed a more temperate and genial climate, so as to allow 

 southern shells to have a wider range northwards. If, on the other hand, they are 

 of an arctic or boreal type, we in the same way infer that our latitudes were once 

 marked by a severer temperature than they now possess, so as to permit northern 

 shells to range farther southwards. This reasoning is strictly correct, and the 

 truth involved forms the basis of all inquiries into the former condition of the 

 earth and its inhabitants. 



The evidence furnished by the northern shells in the boulder-clay series is, 

 aeeordingly, of the most unmistakable kind. These organisms tell us that at the 

 time they lived our country lay sunk beneath a sea, such as that of Iceland and 

 the North Cape, over which many an iceberg must have journeyed, and thus they 

 corroborate our conclusions, derived independently from the deep clay and boulder 

 beds and the striated rock-surfaces, as to the glacial origin of the boulder-clay. 



JSTotwithstandiiig the length of the above quotation, we are tempted 

 to lay before our readers another extract, in which the ancient impres- 

 sion of a stigmaria-fragment of the coal epoch, is gracefully contrasted 

 with ?k fleur-de-lis, sculptured on the same stone in a long-succeeding 

 although now far-vanished age. In the graphic picture of the decay- 

 ing palace, with its hall and chapel, and gloomy dungeons, and the 

 ruined fountain of its court-yard, which furnishes the sculptured 

 matrix of the stigmaria for the author's text, we fancy we reeognize 



* Two of tliese birds (Neoipron pecnoptenis) are stated to have been seen near Kilve, in 

 Somersetshii'e, in October, 1825. One was shot, the otlier escaped. 



t There is not a little difficulty in reasoning satisfactorily as to climatical conditions from 

 the distribution of kindred forms. Even in a single genus there may be a wide range of 

 geographical distribution, so that mere generic identity is not always a safe guide. Thusi 

 the elephant now flourishes in tropical countries, but in the glacial period a long-haired 

 species was abundant in the frozen north. I have above restricted myself entirely to species 

 whose habits and geographical distribution are already sufficiently known. 



