BAGILLT AND HOLYWELL. 11 
grit—if this last is to be distinguished at all from the coal- 
measure sandstones. Assuredly there is a very marked dif- 
ference between the millstone-grit of Hope Mountain, and 
these rotten shales ! 
The fossil organisms found in the cement stone and accom- 
panying shales have quite the estuarine character that is so 
distinctive of the lower coal-measure shales. The plants, which 
are very abundant, consist of Sigillaria and Lepidodendron, and 
grass-like leaves. The shells are Posidonomya Gibsoni (very 
abundant), Aviculopecten papyraceus, Gonialites, and Bellero- 
phon. Pror. Hut (“ Coalfields of Great Britain,” p. 71) gives 
a section of the lower coal-measures or Gannister series, the 
topmost strata of which consists of “ black shales with Aviculo- 
pecten,” and “shales containing Goniatites.” This would seem 
to point to the same horizon as the beds under consideration. 
The most interesting fossils that are found in these beds are 
the Coprolites of fish, which occur as irregular nodules. At my 
request Mr, Srppauu kindly polished some of these, and was so 
much struck with their appearance that he sent them to 
Mr. Curre.t, of London, by whom specimens were mounted as 
transparent objects for the microscope, by which their coprolitic 
character was placed almost beyond a doubt. They contain the 
small bones or scales of fishes—such, at least, is the opinion of 
Mr. Erueripcr, who not only kindly examined these sections, 
but also named the other specimens of shells, &c., for which 
I have to thank him. In his opinion there is a strong proba- 
bility that the Coprolites are the ejectamenta of Megalichthys 
or Rhizodus; and considering their abundance, it is remarkable 
that no remains of the fish themselves have been found. I 
should add that analysis shows the Coprolites to contain a 
large proportion of phosphate of lime. 
From the above-named organisms and the lithological sieictee 
of the beds in which they occur, I venture to doubt the propriety 
of placing them in the millstone grit. It appears probable that 
the line ought to be drawn along the valley in which they are 
found, leaving the narrow strip between that and the top of the 
