324 Revietos — II . B. Woodward — Geology of 



Ireland only twenty- two. The reptiles and amphibia of Germany 

 number twenty-two, those of England thirteen, and those of Ireland 

 four. Again, even among the winged tribes, where the capacity for 

 dispersal is so much greater, Britain possesses twelve species of bats, 

 while Ireland has no more than seven, and 130 land birds to 110 in 

 Ireland. The same discrepancy is traceable in the flora, for while 

 the total number of species of flowering plants and ferns found in 

 Britain amounts to 1425, those of Ireland number 970 — about two- 

 thirds of the British flora. Such facts as these are not explicable by 

 any difference of climate rendering Ireland less fit for the reception 

 of more varied vegetation and animal life ; for the climate of Ireland 

 is really more equable and genial than that of the regions lying to 

 the east of it. They receive a natural and consistent interpretation 

 on the assumption of the gradual separation of the British Islands 

 during a continuous north-westward migration of the present flora 

 and fauna from Central Europe. 



" The last neck of land which united Britain to the mainland was 

 probably that through which the Strait of Dover now runs. Apart 

 from the general subsidence of the whole North Sea area, which is 

 attested by submerged forests on both sides, it is not difficult to 

 perceive how greatly the widening of the channel has been aided 

 by waves and tidal currents. The cliffs of Kent on the one side, 

 and of the Boulonnais on the other, ceaselessly battered hj the sea, 

 and sapped by the trickle of percolating springs, are crumbling 

 before our very eyes. The scour of the strong tides which pour 

 alternately up and down the strait, must have helped also to deepen 

 the Channel. And yet, in spite of the subsidence and this constant 

 erosion, the depression remains so shallow that its deepest parts are 

 less than 180 feet below the surface. As has often been remarked, 

 if St. Paul's Cathedral could be shifted from the heart of London to 

 the middle of the strait, more than half of it would rise above the 

 water" (p. 362). 



In this pleasant strain, Prof. Geikie puts before his readers the 

 great geological facts which science has accumulated in the past 

 fifty years. 



His later American experiences will be read with equal interest. 

 "We heartily commend the volume to our readers. 



II. — Memoirs of the Geological Survey. England anb Wales. 

 The Geology of the Country Around Norwich. (Explanation 

 of Quarter-sheets 66 N.E. and 66 S.E. of the One-inch Geological 

 Survey Map of England and Wales.) By Horace B. "Woodward, 

 F.G.S. (Notes by J. H. Blake, E.G.S., and C. Reid, F.G.S.) 

 Lists of Fossils revised by K. Etheridge, F.R.S. London : 

 Edward Stanford, jun., 55, Charing Cross, S.W., 1881. Eoyal 

 Svo. pp. 216, with 8 Plates, a page Woodcut, and Folding Table. 

 (Price 7s.) 



"/^NE of the earliest geological descriptions of Norfolk," — writes 

 \J Sir Andrew C. Eamsay, in his Notice of this Memoir, — 



" was published by Samuel Woodward in 1833. To the grandson of 



