Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/545

1869.] MACKINTOSH—LANCASHIRE AND CUMBERLAND DRIFTS. 421 breccia than a drift. It is perhaps the most unworkable stuff in the world. The pick can make little, and the spade no impression on it; and it cannot be blasted. During my first visit to this section I could see no indications of stratification, and in my notes called the pinel a "terrible pell-mell accumulation;" but on examining it immediately after fresh faces of it had been exposed by the unusually high tides of the 31st of January, 1869, the appearance of stratification was very strongly marked. It was here and there curved, arched, and false-bedded, though the general dip was to the south at a small angle with the limestone floor underneath, a circumstance which is not easily explained on the theory of accumulation under either water or ice*. The lines separating the beds were as continuous as the number of imbedded stones would apparently allow; and in some places, where there happened to be few stones, the pinel was distinctly laminated. The pinel likewise presented the appearance of having been fractured at intervals; but whether the rents were continued into the underlying limestone I had not an opportunity of ascertaining. One feature of the pinel I think deserves particular attention. On the beach I saw a fallen boulder with hard laminae of loam adhering to one side, and I afterwards found that some of the boulders in the pinel above were partly bedded in thin laminae. As a mere attempt at an explanation of this phenomenon, I would suggest that the stone may have been held at a certain level by a mass of floating ice while the laminae were deposited beneath it, or that after the first imbedding of the stone it may have been partly uprooted by ice floating from N. to S. so as to leave a space beneath it for the deposition of the laminae. Mr. De Rance, of the Geological Survey, on seeing my sketch, expressed his belief that the mere tendency of sea-waves to insinuate themselves under stones firmly imbedded in drift might excavate a cavity on one side which might afterwards become filled with laminated loam, or clay. All these suggestions take for granted the presence of water, and are irreconcilable with the doctrine of accumulation under a great crust of land-ice. Here district or valley glacial action will not apply.

e. Pinel and Contorted Sand and Gravel near Ulverstone.—The difficulty of referring the accumulation of the pinel of this district to land-ice will still further appear when we come to observe the mode of its association with middle drift in the extensive section exposed west of the Ulverstone railway-station. I at first endeavoured to separate the pinel from the sand and gravel above it, but after five or six visits, between which fresh features were exposed, I could only arrive at the conclusion that the pinel is so dove-tailed into the lower part of the sand and gravel as to indicate that both formations must have been accumulated under water, and that ice must in some way have been instrumental in giving rise to the numerous displacements and contortions which render it almost impossible to unravel the details of this remarkable section. Instead of attempting to do

Permian Sandstone at Pontefract.
 * I very lately observed an instance of similar stratification in the Lower