— 6 — 



from this residue; for every spicule, foramenifer and 

 entomostracan shell had to be separated from the mass 

 by means of a moistened hair and afterwards these 

 specimens had to be classified and then mounted for 

 microscopic examination. I found the larger part oi 

 the various forms in the first fortnight of working at 

 the material, but as nearly every day after this my 

 search was recompensed by finding one or two new 

 objects, I continued at the work until I reasonably 

 thought that I had obtained specimens of every form 

 present in the deposit. The result far exceeded my 

 anticipations. The variety of fossil forms, all micro- 

 scopic in point of size, in this mere handful of mate- 

 rial, and their beautiful state of preservation proved 

 extraordinary. There were fossilized remains , entire 

 or fragmentary, of Foramenifera, Sponges, Echinoderms, 

 Annelids ; also of Cirripedia, Ostracoda, Polyzoa, Bra- 

 chiopoda, Lamellibranchiata and lastly. Fishes; but by 

 far the larger part of the fossils, belonged to the fo- 

 ramenifera, sponges, and ostracoda. 



It was a subject for consideration as to which of these 

 three different groups of fossils should be first studied ; 

 but as it appeared that less was known of the sponge 

 remains of the English Chalk than of the foraminifera 

 and ostracoda of this formation, I made up m)' mind 

 to investigate first the fossils of this class. In order 

 however to be able satisfactorily to ascertain the affi- 

 nities of these isolated spicules and morsels of sponge 

 skeleton, I found that it would be necessary to com- 

 pare them with the more or less perfect fossil sponges 

 whose structure had been already determined and that 

 the only collection of sponges which would afford this 

 opportunity for comparison was that made by Pro- 



