54 MESSES. W. E. ANDREWS AND A. J. JUKES-BROWNE [Feb. 1 894, 



between the Lower and Middle groups at the point where Cypridea 

 fasciculata first makes its appearance. This is in the brown and black 

 clay, which is a conspicuous bed in the section, and consequently a 

 convenient plane of division. It is true that Gypris purbeclcensis is 

 still the most abundant form, so that the bed might be grouped 

 with either division, but we prefer to regard the incoming of 

 C. fasciculata as marking the base of the Middle Purbeck Beds. 



A quarry south-west of Lower Chicksgrove, on the southern side 

 of the railway, exposes the same part of the series as that seen at 

 Teffont, and there is a very close correspondence between the two 

 sections, in spite of their being 1| mile apart. The brown and 

 black shaly clay (taken as the base of the Middle Purbeck group) is 

 seen resting on the same marly limestone as at Teffont, but the 

 overlying yellowish shelly shale has thinned out, while the ' Flag- 

 stone ' has thickened to 3 feet, and forms two courses of hard 

 shelly fissile stone. This bed contains Cyrena media, Paludina cari- 

 niferal, Cypridea fasciculata, Estheria subquadrata, with branches 

 of Thvyites and impressions of long reed-like leaves. 



Above the ' Flagstone ' comes a thin shale, and then the ' White 

 Lias,' with just the same thickness as at Teffont, namely 2 feet. 

 The overlying beds, including the ' Scale ' with Modiolce, are similar ; 

 but the succeeding grey shelly limestone is only 1 foot 9 inches 

 thick. It is here a very pure limestone, made up almost entirely of 

 Cyprid and C^c/as-shells, Cypridea fasciculata and C. punctata being 

 abundant. 



The ' Cinder-bed ' is of much the same thickness as at Teffont, 

 but lies in two courses : a lower course of hard grey marly limestone 

 without Ostrece, but containing a few individuals of Cyrena (? media), 

 and an upper course, partly hard and partly loose and rubbly, with 

 many fossils, among which Ostrea distorta, Trigonia gibbosa, and 

 Cyrena media are conspicuous. 



Above the ' Cinder-bed ' come the following in ascending order : — 



Inches. 



1. Soft, brown, marly clay and yellowish shaly marl 8 



2. Soft grey clay, with a lenticular layer of whitish limestone and 



a thin layer of 'beef 9 



S. Hard, marly, oolitic limestone with Cyclas and Cyrena 10 



A quarry on Lady Down, about 1 mile north-west of this, carried 

 a similar section to a somewhat higher horizon, the part above the 

 ' Cinder-bed ' being as follows (in descending order) : — 



Feet. Inches. 



Dark-brown sandy soil 2 



Traces of limestone, witb Archceoniscus 2 



lellowish, calcareous, gritty sand, with layer of reddish-brown 



sandstone at the base 6 



Whitish fissile limestone, in thin layers 4 



Hard shelly limestone, in one massive course 1 3 



Compact white limestone, passing down into flaggy oolitic and 



shelly limestone 1 6 



Laminated marly beds, yellowish and brownish, with layers of 



'beef" and whitish shell-marl 1 4 



Cinder-bed below. 



