506 H. W. Burroics — Crag Foraminifera. 



above suggested, the remaining objections stated by Dr. Bonney 

 would at once disappear. Specimens of Eozoon or other fossils 

 might be infiltrated or filled with these silicates, and while the 

 latter were superabundant they might form separate concretions 

 or grains which might in some cases envelop the fossils or be 

 attached to them in irregular forms, just as one finds in the case of 

 the flints in chalk or the chert in some other limestones.^ 



It is scarcely necessary to say that no objection to the organic 

 origin of the Eozoon can be founded on the fact that many of the 

 specimens are fractured, crushed, bent, or faulted, by the movement 

 of the containing rock, or on the circumstance that well-preserved 

 specimens should be rare, and found chiefly in beds containing 

 silicates capable of injecting their cavities. On the other hand, the 

 circumstance that fragments of Eozoon are abundant in the lime- 

 stone is one of the best possible proofs that we are dealing with 

 a calcareous organism. It would be interesting to describe and 

 figure a number of specimens in our collections illustrating these 

 points ; but to do so would require an extensive illustrated memoir, 

 for which neither space nor means are at present available. 



I observe, in conclusion of this part of the subject, that in any 

 highly crystalline limestone we can hope to find well-preserved 

 fossils only when their cavities and pores have been filled with 

 some enduring siliceous mineral ; but, on the other hand, that porous 

 fossils, once so infiltrated, become imperishable. It still remains 

 to consider shortly new facts bearing on the structure of Eozoon and 

 its possible biological affinities. 



{Part III will appear in the December Number.) 



IV. — On the Stratigraphy of the Crag of Suffolk, with 



ESPECIAL REFERENCE TO THE DISTRIBUTION OF THE EoRA- 

 MINIFERA.^ 



By H. W. Burrows, A.E.I.B.A., etc. 



THE successional order of the strata of the Crag of the Eastern 

 Counties, and the grouping and relationship of the several 

 members of this formation, are here described more especially with 

 regard to the Eoraminifera obtained from them. These remarks on 

 the distribution of the Microzoa in the Crag are based upon the 

 examination of material collected by myself during tlie past eight 

 years, with the exception of some from Tattingstone and Gedgrave 

 (zone g) kindly supplied by Professor Prestwich. The whole of 

 this material has been worked over by Mr. Richard Holland and 

 myself; and Mr. Frederick Chapman has given us some aid 

 with the Tattingstone Crag. Whilst assisting lately in the pro- 

 duction of Part II of the Monograph of the Foraminifera of the 



^ It is a curious comcidence that Dr. Johnston-Lavis has described in the July 

 Number of this Journal, the aqueous deposition at ordinary temperature of crystals 

 of pyroxene and hornblende, in cavities and crevices of bones included in an ash-bed 

 of recent date, and in presence of calcite, apatite, and fluoride of calcium, as in the 

 Grenville Series. This is a modern instance analogous to that suggested above. 



2 Head before Section C of the British Association at Ipswich, Sept. 12th, 1895. 



