POST-TERTIARY FOSSILIFEROUS DEPOSITS. 13 



Other investigators, including Mr. Jamieson, of Aberdeen, Mr. Croll, Mr. Milne 

 Home, Mr. James Geikie, and many other geologists, have largely advanced our know- 

 ledge ; and the reader may be referred to many papers Avhich during the last few years 

 have appeared in almost every volume of the ' Transactions of the Geological Society of 

 Glasgow;' ' Transactions of the Philosophical Society of Glasgow ;' 'Transactions of the 

 Royal Society of Edinbm-gh ;' ' Transactions of the Geological Society of Edinburgh ;' 

 ' Proceedings of the Royal Physical Society of Edinburgh ;' ' Geological Magazine ;' 

 ' Quarterly Journal of the Geological Society,' &c. 



We proceed to describe the various fossiliferous deposits, not being Boulder Clays, 

 which have come under examination for the purposes of this paper. 



There are various striking differences both in position and character existing among 

 the Post-tertiary fossiliferous glacial clays, sands, and gravels, which raise questions of 

 great intricacy and importance, and by which (at any rate for the purposes of study) they 

 must be more or less distinctly separated from each other. 



In the following remarks (as well as throughout this paper) we mean by " Boulder 

 Clay " the first clay which we described ^ among the varieties to which that name has 

 been affixed.^ 



I. Fossiliferous beds, the remains either of the immediate Fre-glacial period or Liter- 

 glacial or Glacial, have been discovered immediately beneath the Boulder Clay, and without 

 any Boulder Clay for their base. 



The fact of the occurrence of these fossiliferous beds in this position does not, of 

 course, either prove them to belong to one epoch or determine their precise age at all, but 

 its significance will be illustrated by the following examples. 



1. Slains and Cruden, Aberdeenshire. 



In the parishes of Slains and Cruden, on the east coast of Aberdeenshire, some 

 thick masses of sand and gravel have been described by Mr. Jamieson, ranging up to 

 200 feet above the sea-level, which are covered in many places " by the red clay of the 

 Glacial Period, containing large boulders and ice-scratched stones," and have no Boulder 

 Clay below them, and which contain a fauna allied to that of the Crag strata of England.^ 



There can be no doubt that the group of species mentioned in the following passage 



1 See page 3. 



2 Jlr. James Geikie, in bis elaborate and remarkable work on " The Great Ice Age," which has been 

 published while these pages are passing through the press, restricts the term Till to the Boulder Clay of 

 this paper. 



^ 'Quarterly Journal Geol. See.,' 1865, vol. xxi, p. 161. 



