39 



brown, is due to the iron they contain. Enclosed in them, as an 

 essential part of their mass, there are minute pieces of shells, and 

 an abundance of foraminifera, the presence of the last pointing 

 to their derivation from the lower beds. Dr. J. E. Taylor, F.G.S., 

 who \Tlsited Muddy Creek with me, was much interested in these 

 nodules, saying they reminded him of the so-called coprolite beds 

 at the base of the Red Crag in Suffolk, and advised me to test 

 them for phosphates. A specimen was accordingly analysed, but 

 the phosphoric acid amounted only to 11*9 per cent., the main 

 ingredients being carbonate of lime, ferric-oxide, and alumina. 



In the following summary and table of species belonging to 

 the respective beds, I have taken account only of the Mollusca 

 proper. The brachiopods, pteropods, and, with one or two excep- 

 tions, the bivalves mentioned have been described by Professor 

 Tate, the Rev. J. T. Woods, and others. The gasteropods are, as 

 yet, only partially described, and I have to thank Professor Tate 

 for permission to quote his manuscript names for a large number 

 of them. The list is not exhaustive, as there are many species 

 yet to be examined. As some species are only known from 

 examples obtained before the distinction between the two deposits 

 was recognised, and the fossils from each kept separate, it is not 

 possible to refer them to the particular bed in which they occur, 

 until fresh specimens are found, and they are, therefore, for the 

 present, merely recorded as Muddy Creek shells. 



I. Summary of Species. 



