142 Correspondence — Rev. 0. Fisher. 



containing the "meres" and "broads" of Norfolk can have been 

 formed by rain ; and, more generally, the condition of the subsoil 

 which I have described under the name of " Trail." CoL Grreenwood 

 has not appreciated the point I endeavoured to raise respecting the 

 windings of the valley (I must not say of, but) in which the Bure 

 runs ; nor yet has he explained the degradation of Lopham ford, but 

 only asserted that it is due to pluvial denudation. 



And now, with respect to Mr. Lankester's remarks upon the Crag 

 and its mammalia, I must re-state that it was solely on Mr. Gunn's 

 published authority that I referred Elephas meridionalis to the Eed 

 Crag. Mr. Whincopp's fine collection does not contain it, unless a 

 piece of ivory may be considered a presumption in its favour. The 

 species, however, is abundant in the Norwich Crag, which is suffi- 

 cient for my argument. The other species mentioned by Mr. 

 Lankester are, I believe, very rare in the Eed Crag, and derivative. 



Much remains to be done before it can be decided whether the two 

 Crags in question are, or are not, of the same age. I incline certainly 

 to the opiaion that they are so ; for they seem to pass gradually 

 one into the other. In the central district of the Crags we find it 

 under Chillesford church, having a close resemblance to the Eed 

 Crag at localities to the south, yet still not identical with it. Going 

 on to Sudbourne, in the pit north of the church, and near the top 

 of the hill, a Crag is seen resting on the Coralline, which has an 

 intermediate character. At Thorpe, near Aldburgh, the type is 

 decidedly that of the Norwich Crag. 



Something might, perhaps, be learnt from digging at Thorpe, 

 were it not for the water. There the Crag rests upon a sandy clay, 

 which is neither Coralline Crag, Eocene, nor Chalk. So also at Wang- 

 ford. I used to consider this the Chillesford Clay, but have been 

 led to abandon that view. What is it ? 



The passage from the Eed to the Norwich Crag seems to occur 

 where the two provinces are separated by a ridge of the older 

 Coralline. This may possibly have marked the boundary between 

 two opposing currents, and may either have been due to diminished 

 erosion at their confines, or may have acted as the cause of their 

 demarcation. The current, sweeping up from the south over a bottom 

 of London clay, would, on account of its warmth, contain a mixture 

 of more southern contemporary forms, as seen at Walton-on-the- 

 Naze, and would bring with it derivata from the London clay and 

 Miocenes of the south, as in the Suffolk bone-bed ; while the other 

 from the north would contain a somewhat more arctic assemblage of 

 species, with fewer and different derived fossils. 



The phosphatic nodules, and many of the fossils of the Eed Crag, 

 come out of the London clay. Why should not its iron be derived 

 from the pyrites so remarkably abundant in the same formation ? 

 An exception may be taken to prove the rule, for at Walton - 

 on-the-Naze we have the Crag resting on the London clay, but 

 quietly deposited, so that Pectimcidi and Pholades are frequently 

 found with their valves united, and the most delicate shells are un- 

 rolled. It is remarkable that at that place we have no extraneous 



