1855.] PRESTWICH BORING AT KENTISH TOWN. 11 



slightly curved ribs, either single or bifurcating, and thickest near 

 the back, where they are crossed by several transverse furrows, which 

 in the cast are but faintly seen ; the lobes of the septa are fully shown 

 in the specimen, and exactly agree with those of A. injlatus ; so that 

 no doubt can exist as to its identity. In mineral condition also the 

 specimen exactly agrees with that of the same species from the phos- 

 phatic nodules in the brick-fields near Cambridge, which are supposed 

 to belong to the top of the Gault. 



" The species is also common in the Upper Greensand in many 

 localities ; M. d'Orbigny quotes it as found throughout France in 

 the Craie chloritee and in the upper part of the Gault, so that every- 

 thing conspires to lead us to place the bed in which this specimen 

 was found, marked No. 80, 1196 feet (No. 5^ of following section), 

 as belonging to the upper part of the Gault. 



"In the tray marked No. 97 (str. 60) is a small fragment of an 

 Ammonite which I think to be A. cristatuSy De Luc, a species only 

 known in the Gault ; but the fragment is so small and so much worn, 

 that I name it with the greatest doubt ; it is in a reddish clay. 



"In tray No. 97, in company with the last-named Ammonite, and 

 also in the tray labelled ' 353,84 metr.' (str. 40), are several fragments 

 of small Belemnites, which correspond in size with B. minimus of the 

 Gault ; but I can state almost with certainty that they do not belong 

 to that species ; their section is more square than in B. minimus^ and 

 the sides have not the double line which marks that species. One 

 specimen differs from all the rest ; it is the point, and appears to 

 have a furrow down each side as in B. bicanaliculatus, Blainville, 

 which M. d'Orbigny places in the Neocomian beds ; it is, however, 

 possible that these apparent furrows may have been produced by the 

 friction of the borer, as the fragment is evidently rubbed. On the 

 whole, no safe conclusion can be drawn from the fragments of Belem- 

 nites. In the tray * 353,84 metres,' there are also some fragments 

 of Ammonites, of which nothing can even be guessed. 



" I can form no opinion whatever about the specimens in the other 

 trays ; some of them are organic, others appear to be only nodules. 



"Yours sincerely, 



" Josejih Prestwich, jun., Usq." " Daniel Sharpe." 



Specimens of these clays and sands have been examined by 

 Mr. Rupert Jones and Mr. Roper for the smaller microscopic fossils, 

 and I am indebted to these gentlemen for the following observations. 



"Tachbrook Street, Nov. 21, 1855. 

 " My dear Sir, — The blue clay (Gault) of the boring at Kentish 

 Town has afforded to my friend Mr. W. K. Parker a plentiful supply 

 of Foraminifera, which I find to be characteristic of the Gault of 

 Kent, &c. ; the red clays and sands, however, of which I have washed 

 and examined four or five specimens, have yielded nothing organic, 

 as far as Mr. Parker or myself have been able to discover. 



" Yours sincerely, 



"T. ilUPERT JoNES»** 



"J. Prestwich, jun.y Esq,, Sec. G,S. ^c. ^c." 



