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to the German Ocean. In this transit, the deflected waters first embayed in 

 these glens, and then filling and pouring through them, would, upon rising to 

 the levels of the successive water-sheds, or low passes, which open a way to 

 the eastern slope of the island, take on a swift current through each notch, 

 and as long as the outpour nearly balanced the influx, this current, temporarily 

 stationary in height, would carve or groove the soft "drift" of the hill-side. 

 But the influx increasing, the stationary level and grooving power of the 

 surface stream would cease, and would only recommence when the flood rising 

 to the brim of another natural dam, a new temporary equilibrium would be esta- 

 blished, a new horizontal superficial current set in motion, and a second shelf 

 or terrace begin to be eroded at the higher level. So each of the parallel roads 

 is conceived to have been produced in the successive stages of the rising of 

 one vast steady incursion of the sea. The lapsing back of the waters, unac- 

 companied by any sharp localized surface-currents, through, the passes, could 

 imprint no such defined marks on the surface, nor accomplish more than a faint 

 and partial obliteration of the terraces just previously excavated during their 

 incursion. This procedure was elucidated by likening it to what takes place 

 when we allow a steady but gradually increasing jet of water to flow into a 

 tank, perforated laterally with several orifices at successive elevations, the 

 outlets permitting a somewhat less rapid rate of discharge than is equivalent 

 to the influx. If such a tank be smeared internally with soft clay, the inpour 

 can be so regulated in respect to its acceleration, that the water, as it rises 

 successively to the levels of the several orifices will take on a horizontal motion 

 or current, through, first the lower hole, and then the second and so on, and, 

 remaining approximately stationary for a brief while on the level of each, will 

 groove the soft clay as it passes out, until it swells above the orifice to reach 

 the next. Some such process as this at the notches which terminate the glens 

 will, it is believed, account for the terraces and all the features which belong 

 to them. 



Glasgow Geological Society. — On Friday, May 24th, the Queen's 

 birthday, a large party of the members of this important society, accom- 

 panied by a number of ladies, took advantage of the holiday by making a 

 lengthened excursion to the far-famed chasm of the " Whangie," Finnich 

 Glen, and the Spout of Ballagan, all on the south-western borders of Stirling- 

 shire. The excursionists, numbering about sixty, left Glasgow at 10 a.m., by 

 two of Menzies' omnibuses, each drawn by four fine horses. The road led by 

 Canniesburn and New Kilpatrick, towards the localities to be explored. The 

 weather proved favourable, and the scenery by the way was much admired, 

 the verdure of the fields having been heightened by the refreshing showers of 

 the previous day. Emerging from the low-lying districts of the Lanarkshire 

 coal-field, the delighted party quickly passed into a rich undulating tract of 

 country, interesting to the eye of the geologist, and leading his imagination 

 back to the time when the whole surface before him lay at the bottom of a 

 stormy and ice-laden sea, when numerous currents, in their irresistible pro- 

 gress, scooped out the valleys, and the unequal denudation of the harder and 

 softer strata contributed to impart to terra firma its present configuration. 

 Such was one of the functions of the " drift-period." Passing the terraced 

 fronts of the eastern termination of one of the ridges of the Kilpatrick range, 

 a quarry at the roadside exposed the columnar structure of the trap-rock, not 

 unusual in other parts of the district, as at the Pillar Craig above the village 

 of Strathblane, and in the isolated hill of Dunglass, opposite the Spout of 

 Ballagan. In this instance the columns are arranged at various angles to the 

 horizon. The finely-wooded heights bounding the Strathblane Valley on the 

 south now came into view, while on the north were observed the conical height 



