506 MESSES. WHITE AND TKEACHER ON THE [Aug. I906, 



bidiformis, and Coscinopora quincuncialis are very common, and 

 one specimen of Offaster pillula was obtained. 



Abundant as are the remains of Actinocamacc granulatus and 

 EcJiinocorys scutatus in bed (4), they form but the forerunners of 

 the swarms which come in at the base of the succeeding division (5). 

 The guards or tests of these animals occur at intervals of a few inches 

 all along the face of the pit at that horizon, and it is no uncommon 

 experience to find three or four of each almost in contact. They 

 lie most thickly upon, or within 3 inches above, the uneven, 

 oyster-encrusted pavement at the top of the rock-bed (4). We 

 estimate the remains of A. granulatus to be fully twice as abun- 

 dant in the lowest 6 inches of bed (5) as in any band of the same 

 thickness in the Upper Brown Chalk of Taplow Court. 1 Their 

 granulation is, as a rule, very pronounced ; and the ratio of the 

 depth of their cavities to their total length ranges from 1 : 4| to 

 1 : 6. Some are distinctly quadrate in section ; and one imperfect 

 guard, with a deep, steep-sided, quadrate alveolus, is probably 

 referable to Actinocamacc quadratics. All are partly corroded by 

 soil-water, but the bulk of them seem to have been complete at 

 the date of deposition ; and theundecayed portions of the surface of 

 the broken specimens show no obvious signs of attrition. 



EcJiinocorys scutatus is represented in a nicely-graduated series 

 of stunted forms, to the extremes of which the terms ' somewhat 

 inflate-pyramidate ' and ' very depressed ovate ' may be fitly applied. 

 The average measurements of the. test are: length = 48, height = 

 34 mm., and we have only two examples the dimensions of which 

 greatly exceed or fall far short of these. One of them, of subgibbous 

 form, measures, in length = 67, height = 45 mm. : the other, of a 

 flattened ovate shape, measures, in length = 44, height = 26 mm. 



The general facies of the species here is quite distinct from that 

 presented in the higher parts (D and E) 2 of the Taplow Phosphatic 

 Chalk, although the rarer, depressed, form noticed there falls 

 naturally into the Winterbourne series. The tests of EcJiinocorys 

 here are usually in a very brittle state, crumbling on removal from 

 the chalk, and leaving more or less perfect internal casts, which 

 not seldom contain a decomposed pyrite-concretion. 



Offaster pillula is common where the remains of Actinocamacc and 

 EcJiinocorys are most abundant. It exhibits no abnormalities. 



Actinocamacc, EcJiinocorys, and Offaster all become scarce at 

 about 1 foot above the base of bed (5), and have not been found in 

 the upper half of that division, which, indeed, has yielded few 

 megascopic fossils besides Ostrece, Pecten cretosus, Spondylus latus, 

 and RJiyncJionella plicatilis. Casts of the two last-named fossils 

 occur in the angular flints of the overlying Drift. 



The names of the fossils identified in the several beds of this 

 section are tabulated on the following page. 



1 Quart. Journ. Geol. Soc. vol. lxi (1905) pp. 472-75. 



2 Ibid. loc. cit. 



