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 
