of Edinhiirgh, Session 1880-81. lix 



the visitor might get across as soon thereafter as possible, and take 

 the full advantage of the time that would elapse before the tide 

 made it necessary to recross again. 



On the occasion of our excursion we arrived a short time before 

 the falKng tide had left it, and instead of waiting, we determined 

 to wade through, so as to get more time on Oransay. We took to the 

 water, which was from twelve to eighteen inches in depth, and had not 

 gone far when we found that there were very strong currents running 

 westwards and eastwards towards the ojien Atlantic, and here and 

 there uj^on the sandy bottom we saw sinuous markings that might 

 have been the grooved tortuous tracks of immense eels as they made 

 their way seawards ; and we went on in the hope that as we got 

 further from the shore we would come across one of these fish. 



But though the courses were numerous still we saw nothing that 

 to our mind could make them, until suddenly, about mid-channel, 

 we observed that one of these markings seemed either to begin or 

 end at the foot of a large stone ; but though we lifted the masses of 

 sea-weed that were attached to it, in the hope that below we should 

 find a veritable sea ser^jent, still we were disappointed. A little 

 fiu'ther on we came to another which again terminated at a stone, 

 and as we looked on, considering what could be the solution of the 

 problem, the stone moved; we thought we must be mistaken, so we 

 watched it carefidly, and after a pause it began to travel westwards, 

 and having got over a ridge of sand into deeper water, it proceeded 

 much faster ; and as it journeyed, buoyed by the sea-weed, and 

 dragged by the current, it left a trail behind. At last the mystery 

 is solved, the buoyant power of the air-vessels of the sea-weed is 

 half lifting the stone from the ground, and as the current carries 

 the weed along it waves from side to side, conveying the same 

 motion to the stone, which leaves a winding impression on the 

 sand. A further examination of the courses showed us that aU were 

 not alike, some being quite straight, and we noticed several where 

 the stone, after travelling a straight course, had been left dry upon 

 tlie sand, and when the tide flowed again had been driven off at an 

 angle back iipon its fu'st track, leaving a trail much like the letter 

 V. Some courses intersected each other, and occasionally sinuous 

 and straight courses were to be thus found in combination. 



Now, may this not cause reflection as to what may be the real 

 solution of some supposed reptilian marks upon sandy or muddy 

 beaches, Avhether ancient or modern, especially if they occur where 

 there is a great fluctuation in the rise and fall of the tides, and at 

 the same time a strong current 1 



