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Vol.. II. X, OCTOBER, 1893. No. 10. 



SEAWEED TRACKS IN SAND. 



BY PROF. W. J. SOLI^AS, I.I..D., F.R.S. 



The shining, level, sandy flats of the seashore, spreading like 

 a satiny quilted margin to the land, possess a charm to which 

 we all succumb. The youngsters with their toy spades, the 

 artist, and scientific wanderers of many kinds, open their ears 

 to the enticement " Come unto these yellow sands," and though 

 with various aims they go, their pleasure is the same. 



Our coast is rich in wide expanses of rippled sand, but rarely 

 will the geologist find one more full of interest than that 

 which occurs at Sutton, on the coast of Howth. The ripple- 

 marks, in their diverse character, afford an interesting study in 

 connection with those so commonly met with on the sandy 

 surface of ancient bedded rocks ; the pits and hillocks which 

 mark the home of the lobworm underground, will call to mind 

 the trumpet-mouthed burrows which penetrate the Cambrian 

 quartzite at Bray ; and the crabs, sidling speedil}^ to some 

 lurk-hole, leave impressions on the sand that we may take 

 careful note of, hoping some day to parallel them with proble- 

 matic markings on the sands of ancient buried seashores, 

 lycss familiar than these common seashore sights are the long 

 tracks to which we now call attention. Varying in width, 

 frequently about an inch across, with raised margins, and a 

 central groove which is minutely ridged and furrowed trans- 

 versely, they run for long distances, undulating in wide 

 curves (plate 6, fig. i) to end in a little well-marked pit. To 

 the question, " What made them ? " everyone I have asked has 

 immediately replied to the effect: "Evidently a wandering 



