PROCEEDINGS OF GEOLOGICAL SOCIETIES. 
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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 24:th, 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 tlie " 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 tiie 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 Yalley on the 
south now came into view, while on the north were observed the conical height 
