On the Boulder Clay of Caithness. 397 



ties in which the various organisms described by him were 

 found." I am sorry that, however willing to comply with 

 the above request, space will not permit me now to do more 

 than mention a few of the localities whence the organisms 

 were taken, they are so many ; for, as I stated in my former 

 paper, the "boulder clay may be traced all over Caithness." 

 Where excavations have been made for any purpose, and 

 rivers and burns have acted on these deposits, good sections 

 are to be met with, and in all organisms in greater or less 

 abundance are to be found ; — at Wick, on both sides of the 

 harbour, and up the river to the Loch of Watten. The 

 cliff at the South Head is also rich in clay and organisms. 



The Burn of Milton, near Wick, where a new cut for the 

 water was made a few years ago, has also proved a rich 

 mine ; the cutting exposed many roots of trees of pretty 

 large size, and many rootlets, in two or three places in its 

 course ; some of these had penetrated the very hard clay to 

 the depth of four or five feet. As well as the wood itself, 

 several hard sandy tubes and root-like objects were in the 

 clay. These had taken the place of some of the decayed roots 

 and rootlets, as might be seen by small strings of the 

 wood in many of these sandy masses ; they were red and 

 hard, evidently caused by the iron which had cemented the 

 sand together. The trees to which these roots and rootlets 

 belonged had evidently grown on the banks of a loch which 

 once existed there. All traces of the trunks are lost, and 

 the places on which they grew are covered with a thick 

 deposit of peat-like matter, no doubt drifted, and by which 

 the loch was filled. The course of the ancient stream in 

 its windings, with its pebbly bottom, maybe seen in various 

 places in the newly cut banks. One of the largest pieces of 

 vegetable matter showed a coniferous structure. These 

 trees were evidently of a later age than the boulder clay. 

 The Burn of Haster all the way up shows fine sections; and 

 as the water of the burn, with frost and rain, are continually 

 acting on them, fresh faces are often exposed, and fine 

 collections may be gathered. Here I first got Foraminifera 

 in a pretty little nest of sand ; since that, at this spot, and 



