224 THE WONDERS OF GEOLOGY. Lect. III. 



natural groups of this series, lias established the following 

 subdivisions of the deposits that occupy the eastern coast 

 of England : — 



1. Coralline or lowermost Crag. A series of calcareous and marly 



strata, loose white sands, layers of shells and corals, and concre- 

 tionary bands of stone. It abounds in shells, echini, sponges, 

 and corals, (especially of the genus Fascicularia,) and these 

 occur in so perfect a state as to indicate that they lived and 

 died on the spot ; for many of the sponges and corals are in the 

 upright position in which they grew. This group is upwards 

 of twenty feet in thickness, and extends along the coast of 

 Suffolk, over an area of twenty miles in length and three or 

 four in breadth. 



2. Red or Norfolk Crag. So named from its deep ferruginous 



colour. It consists principally of quartzose sand, with commi- 

 nuted and water worn shells, corals, bones and teeth of fishes, and 

 other fossil remains. These beds, when occurring in the same 

 locality, are invariably superimposed on the Coralline Crag. 

 They attain a thickness of upwards of forty feet, and abound in 

 marine shells, especially numerous species of Murex, Buccinum, 

 and Fusus ; among the latter is the Fusus contrarius, (so named 

 because the spiral convolutions pass from the right to the 

 left, instead of in the opposite and ordinary direction,) a well- 

 known shell, formerly in great request among collectors.* 



3. Mammaliferous, or fiuvio-marine Crag. Sandy loam, and clay, 



more or less charged with shelly detritus ; it occurs in certain 

 localities at Southwold, Norwich, Cromer, &c. and contains 

 bones and teeth of several extinct mammalia, associated with 

 those of existing and indigenous species. 



4. Insulated patches of lacustrine beds with mammalian remains. 



Above the whole of these deposits, is the usual alluvial sedi- 

 ment and drift, in which are vast numbers of bones and teeth of 

 Elephants and other pachyderms, including a species of Mas- 

 todon, and the Irish Elk.f 



* See Parkinson's Organic Remains of a former "World ; vol. iii. 

 pi. 6, fig. 5. 



f Of the Mastodon thirteen teeth have been found. More than thirty 

 years since, tusks of mammoths, horns of Bos and Aurochs, and 

 antlers of the Irish Elk, from near Walton Nase, in Essex, were sent 

 to me by G. B. Greenough, Esq. 



