252 VINE : POLYZOA OF THE LOWER AND UPPER GREENSAND. 
Ill this paper, therefore, I shall confine myself to the Polyzoa of 
the Upper and Lower Greensands only. I do this for two reasons. 
The Polyzoa of the Gault, Lower Chalk, Red Chalk, and Upper Chalk 
must be separately dealt with, as new material is constantly coming 
to hand, and even the Polyzoa of Farriiigdon and Warminster would 
be all the better appreciated if rigidly overhauled. In dealing with 
the Cambridge Greeiisand species, now that fairly ample material has 
been placed in my hands, it will be more advantageous as a palseonto- 
logical sketch to separately classify, especially in the sjaioptical table, 
the Polyzoa dealt with. In the first place many large and small 
fossils, belonging undoubtedly to the Greensand of Cambridge, are 
encrusted with colonies of Polyzoa, some of which are very fine. I 
have before me a list, twenty-four examples at least, sent by Mr. 
Jesson, and briefly referred to in my first paper (p. 3). These will 
now constitute true Cambridge Greensand species, and their tabula- 
tion will be altogether distinct. The second group of Polyzoa are 
derived probably from erosion or denudation of rocks of the ages of 
the Cambridge Greensand and Lower Chalk. In December, 1884, 
Mr. Jesson wrote me as follows respecting the derived forms. ''As 
to the exact horizon of the Polyzoa from Cambridge I think it is quite 
impossible to say anything sufiicieiitly accurate to be of any use. 
They come from the washings of the phosphate beds, but naturally 
in the excavations there is a gTeat admixture of various horizons. I 
believe the material came from the Coldhams' Lane Pits." These 
remarks are all the more valuable, because, having picked from the 
fine siftings of this debris a goodly number of Foraminifera and Eiito- 
mostraca;'" belonging evidently to various cretaceous horizons, a note 
as to their source may prevent future misunderstanding. The 
Polyzoa derived from these washings will be tabulated under the 
head Phosphate Beds." 
Sir Charles Lyellf places the Chloritic Series, or Upper Green- 
sand, at the base of the Chalk Marl, and above the Gault. This is 
the location of the " Cenomanien" division of the Cretaceous Beds by 
French authors. In his remarks on the series, Lyell says, " Accord- 
* See Part iii., further on. 
t Elements, p. 112 and 226, ed. 1878. 
