762 PROF. J. W. JUDD ON THE NATURE AND RELATIONS OF 
The remains of Echinoderms from these two wells, consisting, as 
they do, for the most part of disjointed ossicles, plates, and spines, 
are very difficult to determine. Among the most common are 
marginal plates and eye-plates of an Asterid. Precisely similar 
forms, though less perfectly preserved, occur in the washings from the 
Bradford Clay. Eye-plates of like kind are figured by Quenstedt 
in his ‘ Petrefactenkunde Deutschlands’*. The marginal plates are 
so like those of Astropecten, that I have little doubt that they 
must be referred to that common Oolitic genus. 
The Crinoids have been kindly examined for me by Dr. P. H. 
Carpenter, who states that they represent arm-joints and cirrus-joints 
of Pentacrinus scalaris and of another Pentacrinid. He refers other 
fragments with doubt either to Bourgetierinus or Thiolliericrinus. 
EXPLANATION OF PLATE XXXITII. 
Chalk of the Zone of Belemnites plenus From a depth of 704 ft. in the 
Richmond Weill. 
Fig. 1. Shows the appearance of a polished surface of this chalk, magnified two 
diameters. The lighter portions are the included fragments of 
Globigerina-chalk ; the darker portion shows the matrix made up of 
fragments of various organisms, some of these fragments being of 
considerable size. 
2. Illustrates the appearance of the rock when seen in thin section by 
transmitted light with a low power. A is the Globigerina-chalk, of 
an included fragment of which the edge is seen in the slide. It 
appears to be almost entirely made up of fragments of minute 
Globigerine. A few other forms of Foraminifera occur, among which 
Textularia is conspicuous. B shows the character of matrix which 
encloses the fragment. 
Discussion (February 6, 1884). 
Prof. Prestwicu spoke of the value of the paper and the good 
fortune that the excavation had been watched by such experienced 
geologists. He called especial attention to the two divisional and 
apparently denudational zones in the Chalk, and to the persistence 
of the total thickness of the Chalk in the London area. But the 
main interest of the paper consisted in the sub-Cretaceous strata. 
The specimens from the boring at Meux’s Brewery, which were very 
fragmentary, were supposed to be Neocomian, and so led to the hope 
that the sand-beds might set in at a short distance to the south. 
It was, however, now clear that these calcareous beds were Oolitic. 
He did not, however, agree with Prof. Judd in thinking the red 
beds Triassic; they appeared to him more probably Old Red Sand- 
stone, though doubtless it was difficult to say. If they were the 
former it would be less likely that Paleeozoic beds, as evidenced in 
the conglomerate, should occur in the vicinity. If the water rose to 
* Tab. 91. 
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