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548 REPORT—1904. 
5. Note on Lower Cretaceous Phosphatic Beds and their Fauna, 
By G. W. Lampiuen. 
It has been customary to regard the fossils more or less imperfectly preserved 
in the condition of phosphatic casts in different parts of the English Lower 
Cretaceous series as derivative from the Jurassic rocks. In previous papers the 
writer has brought forward evidence to show that the fauna of such beds at 
Speeton and in Lincolnshire is not derivative, but occurs at its proper horizon 
and, so far as it goes, indicates the life of the period. Personal investigation of 
the localities, and of the fossils obtained from the ‘coprolite beds’ at Upware, 
Potton, and Brickhill, has led him to conclude that in these deposits also 
the greater part of the so-called derivatives are really of Lower Cretaceous 
age. Thus one of the most abundant phosphatic fossils of these places is the 
ammonite, usually fragmentary, which has habitually been named Amm. biplea, 
but belongs in almost every case to one or another of several allied species of 
Lower Cretaceous Olcostephani. Most of the lamellibranchs can likewise be best 
matched by Lower Cretaceous forms; and there are good grounds for suspecting 
that many of the saurian- and fish-remains from the above-mentioned places 
and from the Faringdon ‘Sponge Gravels,’ which have been classed as Jurassic, 
are true Lower Cretaceous forms. 
It is acknowledged that the presence of transported pebbles of older rocks in 
the deposits at Upware, Potton, and Faringdon renders the occurrence of deriva- 
tive fossils at these places more probable than in the case of the Speeton and 
Lincolnshire ‘ coprolite beds’; and in the collections examined a few specimens 
were noticed that seem to have been washed from older rocks. But the writer 
believes that these instances are exceptional, and he urges that no fossil should be 
set down as derivative unless the evidence is conclusive, as much confusion has 
arisen through the unquestioning adoption of the hypothesis of derivation. 
While there is still much to be learnt as to the physical conditions requisite 
for the concretion of phosphatic nodules and for their segregation into bands, it 
seems clear that an important determinative was the existence of submarine 
currents occasionally impinging upon the sea-floor with sufficient strength to sweep 
away the matrix in which the nodules had been formed, so that there was a 
gradual accumulation of the partially eroded nodular residues. Such residues, 
though of inconsiderable thickness, may represent a long period of submarine con- 
ditions, The term ‘aggregate deposits’ has been suggested by J. F. Blake for 
beds of this character. 
6. On Marine Fossils from the Ironstone of Shotover Hill, near Oaford. 
By G. W. Lampiueu. 
(Communicated by permission of the Director of the Geological Survey.) 
_ The presence of casts of marine fossils, including Trigonia, Perna, and Modiola, 
in an ironstone rock on Shotover Hill resembling in appearance that which 
contains the Lower Oretaceous freshwater fossils, Unio, Cyrena, and Paludina, 
has long been known, but the horizon at which these marine fossils occur has 
not hitherto been ascertained. The writer found that these marine forms occur at 
the base of the Ironsand series, in a rock which appears originally to have been a 
sandy limestone, now converted, sometimes wholly and sometimes partly, into an 
ironstone by the replacement of the lime by iron. In other parts of the outcrop 
the limestone has been silicified, and the fossils are then almost entirely obliterated. 
From its position and fossils it is concluded that this rock belongs to the Port- 
landian series, and represents a portion of the Upper Portland stone, converted to 
its ee state through the infiltration of ferruginous waters from the overlying 
ironsands. 
