360 



PLEISTOCENE GEOLOGY OF THE THAMES VALLEY. 



mild winters, for the ivy is extremely sensitive to winter cold. 

 Botli the character of the flora and the position of the deposit 

 suggest correlation with the temperate plant beds at Hoxne, 

 which lie between the Boulder Clay and the deposit with Arctic 

 species. The Ivy and the Poplar have not previously been 

 recorded as British fossils." 



We sent some samples of the Blue Clay (No. 10) of the 

 Orsett Road Section to Mr. C. Reid who says of these that they 

 yielded remains of mosses, but of indeterminable species. It is 

 of interest to note Mr. Reid's conclusion as to the character of 

 the climate of the Brickearth stage as it exactly corresponds 

 with our own, arrived at from a study of the lithological and 

 tiie otlier pal^eontological characters of the beds. 



PAL.^ONTOLOGICAL SUMMARY OF THE PLEISTO- 

 CENE DEPOSITS OF GRAYS. 



No. of Species. 

 30 

 3 



Mammalia 



Aves 



Reptilia 



Amphibia 



Pisces 



Mollusca 



Ostracoda 



Plantae 



Total 



I 

 2 



6 



61 



6 



16 



125 



VI. PHYSIOGRAPHY. 



The physiography of the Grays Thurrock Area presents 

 certain features of great interest, which features are likewise of a 

 somewhat complicated nature. In the present section of this 

 communication we propose to describe one of the physiographical 

 features of the eastern portion of the district, and this description 

 will embody the results of oiu' observations on the structure and 

 formation of severaJ valleys which intersect and diversify the 

 plate lu formed by the High Terrace Drift. 



The i'alleys referred to may be likened to wide, shallow 

 grooves of about thirty feet in depth, varying from a quarter to 

 half a mile in breadth and about three-fourths of a mile to one mile 



