INTRODUCTION. vii 



Mr. Richard Cowling Taylor published, in the 'Philosophical Magazine,' 1822-24, 

 some observations on the Norfolk Cliffs, as well as a Paper, in the 'Geological 

 Transactions,' upon the Tertiary deposits of Norfolk and Suffolk ; some good figures of 

 Crag Corals were also given by him in the ' Magazine of Natural Histoiy,' 1830. 



In 1826, Mr. Robberds published some 'Observations on the Eastern Valleys of 

 Norfolk.' 



In 1833, 'An Outline of the Geology of Norfolk' was published by Samuel 

 Woodward the elder, in which there are some good figures of Crag fossils, from the 

 beds in the immediate neighbourhood of Norwich, relating only to the Mammahferous 

 Crag. 



The geological features of the upper Tertiaries of this country, more especially 

 those portions from which the shells here illustrated have been extracted, have been 

 ably delineated by Mr. Lyell, in his ' Principles' as well as in his 'Elements of Geology;' 

 and also in a special Memoir, published in the 'Magazine of Natural History' for 1839. 



Mr. Charlesworth also published a series of Papers in the ' PhDosophical Magazine' 

 for 1835, in which the Crag Formation was separated into ^/^ree .different Periods, the 

 oldest of which he designated the " Coralline Crag," as expressive of its contents, that 

 Formation being in some places composed entirely of Zoophytic remains. The 

 succeeding Period, or " Red Crag," was so denominated from its peculiar ochreous 

 colour, the beds being strongly stained by large quantities of the hydrous oxide of iron ; 

 but it was considered as geologically distinct, on account of the absence of the o-reat 

 mass of Zoophytes peculiar to the lower beds, as well as of the introduction of a 

 new group of Testacea. A further examination of what had previously been considered 

 as an extension of the Red Crag Formation into Norfolk, induced that author to 

 suspect the Crag of Norfolk to be of posterior age, and, as position in this case was no 

 guide to such determination, he appealed to the certain evidence of zoological 

 distinction, which presented a more recent aspect than either of the preceding ; and 

 as amongst its imbedded fossils are the remains of numerous Mammalia, he gave to this 

 Formation the title of "Mammahferous Crag." These terms are employed in the 

 present work. 



In 1836, Mr. John Morris published some observations, in the ' Magazine of Natural 



