42 Remains of Vertebrate in Tertiary Deposits. 



and on Thorp Common, near Aldeburgh. This stratum, as 

 regards relative age, may be looked upon as holding a station 

 intermediate to the red crag, and those deposits in which the 

 testaceous remains appear to belong, almost exclusively, to 

 existing species of mollusca. 



The beds above the chalk in Norfolk, Suffolk, and Essex, 

 may be grouped into two sections, determined by the presence 

 of terrestrial mammalia throughout a part of the series, which 

 in descending order will be as follows. — 



A. Beds furnishing remains of Terrestrial Mammalia. 



1. Superficial gravel, containing bones of land animals, pro- 

 bably washed out of stratified deposits. 



2. Superficial marine deposits of clay, sand, &c. in which 

 the shells, very few in number, (10 or 15 species), may 

 all be identified with such as are now existing. 



Examples. — Brick earth of the Nar, Norfolk. 



3. Fluviatile and lacustrine deposits, containing a consi- 

 derable number of land and fresh-water shells, with a 

 small proportion of extinct species. (Mammalian remains 

 in great abundance.) 



Localities. — Ilford, Copford, and Grays, in Essex ; Stutton 

 in Suffolk. 



4. Mammiferous crag of Norfolk and Suffolk, hitherto con- 

 founded with red crag, containing about eighty species 

 of shells ; proportion of extinct species undecided. 



Localities. — Bramerton, near Norwich; Southwold, and 

 Thorp, in Suffolk. 

 B. Beds in which no traces of Terrestrial Mammalia have yet been observed. 



1. Red crag, containing 150 to 200 species of shells ; pro- 

 portion of extinct species undetermined. 



Localities. — Walton and Dovercourt, Essex; Felixstow, 

 Newbourne, and Bawdesey, Suffolk. 



2. Coralline crag, containing 300 to 400 species of shells ; 

 proportion of extinct species undetermined. 



Localities. — Ramsholt, Sutton, Tattingstone, (beneath red 

 crag), Aldeburgh, Orford. 



3. London clay. 



4. Plastic clay. 



The author next adverts to the remains of birds, which he 

 has recently obtained, on several occasions, in the mammife- 

 rous stratum of crag. The bones, principally belonging to 

 the phalanges, have not yet been minutely compared with 

 the corresponding portions of skeletons of existing species. 

 These remains occur at Southwold, and have undergone the 

 same chemical change as the bones of mammalia. 



