748 PROF. J. W. JUDD ON THE NATURE AND RELATIONS OF 
have thinned out or to have been altogether removed by denudation 
at Kentish Town, a little to the north of the latter place, and no 
trace of them was found at Crossness, Turnford, or Ware. It appears, 
therefore, that whatever may have been the former extent of these 
Lower-Oolite strata, they are now confined to the southern part of 
the metropolitan area, and abut against the southern flank of the 
great Paleeozoic axis. 
Although, as we have seen, there is a general correspondence in 
the characters and fossils of the Great-Oolite strata in the two 
localities in which they have been found, yet, when critically 
examined, some very interesting and suggestive differences become 
apparent. 
Under Richmond the strata consist of compact limestones, with 
a very thin interstratification of clay, the only sandy beds being 
found towards the base of the series. The fossils found at Richmond 
are not only all truly marine but are for the most part such as 
would inhabit moderately deep water. Nor do the fossils, as a 
rule, appear to be rolled and waterworn, as is the case with those 
found in littoral deposits, but they are quite fresh and unbroken. 
In this connection the evidence afforded by the thin but highly 
fossiliferous band of clay at Richmond is singularly valuable. This 
clay band, as was remarked to me by Mr. G. R. Vine, greatly 
resembles those found at Minera and elsewhere, intercalated among 
the beds of Carboniferous Limestone. The Bryozoa and Pentacrinites 
were evidently growing in profusion on the ocean floor at the time 
they were overwhelmed, and were killed and entombed by an influx 
of excessively fine muddy sediment. 
Very different is the state of things found under the Tottenham 
Court Road. There the specimens are all much broken and water- 
worn, many of them being coated with a thick layer of ecalcic 
carbonate. It is evident that the beds containing these fossils were 
accumulated in much shallower water than those at Richmond. 
Among the fossils found at Meux’s well Mr. C. Moore detected some 
which he suspected to be terrestrial, freshwater, and brackish-water 
forms, referable to genera like Hydrobia, Valvata, Potamides, and 
Potamomya ; and to some extent Mr. Moore’s views were borne out 
by the examination of these very imperfect shells by Dr. Gwyn 
Jeffreys and Mr. C. J. A. Meyer. This and the dwarfed condition 
of many of the Gasteropoda and other shells led Mr. C. Moore to 
the conclusion that while all the strata were of shallow-water origin, 
some of them were probably deposited in brackish water, while a 
number of the fossils might have been washed down by rivers. 
A very interesting circumstance in connexion with the Great- 
Oolite deposits at Messrs. Meux’s well, which was noticed by Mr. C. 
Moore, was the occurrence of coaly fragments in some of the beds. 
I have myself found a considerable number of such fragments in a 
specimen from a depth of 1046 ft. These fragments appear to 
me to be very similar to the imperfect Jurassic coals of Brora and 
the Western Isles of Scotland. The engineer at Messrs. Meux’s 
Brewery informed me that at some periods during the boring in the 
Oolitic strata, the water forced down the well came up “as black 
