RAMBLES OF A GEOLOGIST. 311 



was the boulder-clay in which they occurred. Almost the 

 first pebble which I disengaged from the mass, however, set- 

 tled the point, by furnishing the evidence on which for seve- 

 ral years past I have been accustomed to settle it ; it bore 

 in the line of its longer axis, on a polished surface, the fresh- 

 ly-marked grooves and scratchings of the iceberg era. Still, 

 however, I had my doubts, not regarding the deposit, but 

 the shells. Might they not belong merely to the talus of 

 this bank of boulder-clay ? a re-formation, in all probability, 

 not more ancient than the elevation of the most recent of the 

 old coast lines, perhaps greatly less so. Meeting with an 

 intelligent citizen of Wick, Mr John Cleghorn, I requested 

 him to keep a vigilant eye on the shells, and to ascertain for 

 me, when opportunity offered, whether they occurred deep 

 in the deposit, or were restricted to merely the base of its 

 exposed front. On my return from Orkney, he kindly 

 brought me a small collection of fragments, exclusively, so 

 far as I could judge, of Cyprina islandica, picked up in fresh 

 sections of the clay ; at the same time expressing his belief 

 that they really belonged to the deposit as such, and were 

 not accidental introductions into it from the adjacent shore. 

 And at this point for nearly two years the matter rested, 

 when my attention was again called to it by finding, in the 

 publication of Mr Keith Johnston's admirable Geological 

 Map of the British Islands, edited by Professor Edward For- 

 bes, that other eyes than mine had detected shells in the boul- 

 der-clay of Caithness. " Cliffs of Pleistocene," says the Pro- 

 fessor, in one of his notes attached to the map, " occur at 

 Wick, containing boreal shells, especially Astarte borealis." 



I had seen the boulder-clay characteristically developed in 

 the neighbourhood of Thurso ; but, during a rather hurried 

 visit, had lacked time to examine it. The omission mattered 

 the less, however, as my friend Mr Robert Dick is resident 

 in the locality ; and there are few men who examine more 



