TRANSACTIONS 01? SECTION C. 525 



to point to a great want of homogeneity in the interior of our planet, and might 

 suggest a possible cause for some disturbance of equilibrium. 



I have mentioned Professor Haughton among those who, from mathematical 

 considerations, have arrived at the conclusion that a geographical change in the 

 position of the axis of rotation of the earth is not only possible but probable. In 

 a recent paper, however, he has maintained that, notwithstanding this possibility 

 or probability, we can demonstrate that the pole has not sensibly changed its posi- 

 tion during geological periods. He arrives at this conclusion by pointing out that 

 in the Parry Islands, Alaska and Spitzbergen, there are Triassic and Jurassic de- 

 posits of much the same tropical character, and then by a geometrical method 

 fixing the north pole somewhere near Pelrin, and the south pole in Patagonia, 

 within seven hundred miles of a spot where Jurassic ammonites occur, shows that 

 such a theory is untenable. In the same way he fixes the pole in Miocene times 

 near Yakutsk, within eight hundred miles of certain Miocene coal beds of the 

 Japanese islands. These objections are at first sight startling, but I think it will 

 he found that if, instead of drawing great circles through certain points, we regard 

 those points as merely isolated localities in a belt of considerable width, there is 

 no need of fixing the pole of either the Jurassic or the Miocene period with that 

 amount of nicety with which Professor Haughton has ascertained its position. 

 The belt may indeed be made to contain the very places on which the objection is 

 founded. Still the method is a good one, and I hope that as our knowledge of 

 foreign geology extends it may be still further pursued. There is, however, one 

 farther consideration to be urged, and that is as to the safety of regarding all de- 

 posits of one geological period as contemporaneous in time. Although an almost 

 identical flora may be discovered in two widely-separated beds, it appears to 

 me that chronologically they are more probably of different ages than absolutely 

 contemporaneous; and, inasmuch as the duration of the Miocene period must 

 have been enormous, there would be time — if once we assume a wandering of the 

 poles — for such wandering to have been considerable between the beginning and 

 end of the period. 



I must not, however, detain you longer upon this phase of geological specula- 

 tion, but will advert to a subject of more practical interest, the discovery of 

 Palaeozoic rocks under London. So long ago as 1856 the Kentish Town boring 

 had shown that immediately below the Gault red and variegated sandstones and 

 clays occurred, which Professor Prestwich regarded as probably of Old Red or 

 Devonian age. The boring of Messrs. Meux and Co. has now shown that under 

 Tottenham Court Road, at a depth of little more than nine hundred feet from the 

 surface, there are true Devonian beds, with characteristic fossils, and that Mr. 

 Godwin-Austen's prophecy of the existence of Palaeozoic rocks at an accessible 

 depth under London has proved true. Professor Prestwich, from a consideration 

 of the French and Belgian coal-fields, inclines to the belief that in the district 

 north of London carboniferous strata may be found. Unfortunately the expense 

 of conducting deep borings, even with the admirable appliances of the Diamond 

 Boring Company, is so great that I almost despair of another experimental bore- 

 hole like that carried out in the Wealden district under the auspices of Mr. Willett, 

 being undertaken. 



In the department of theoretical geology I would call your attention to some 

 experiments by M. Daubr6e, of which he has given accounts at different times to 

 the French Academy of Sciences. In these experiments he has attempted to re- 

 produce on a small scale various geological phenomena, such as faulting, cleavage, 

 jointing, and the elevation of mountain chains. Although the analogy between 

 work in the laboratory and that on the grand scale of nature may not in all cases 

 be perfect, yet these experiments are in the highest degree instructive, and reflect 

 no little credit on the ingenuity of the distinguished chief of the Ecole des Mines. 

 "With regard to recent progress in palaeontology, I must venture to refer you to 

 Professor Alleyne Nicholson's inaugural address lately delivered to the Edinburgh 

 Geological Society, but I cannot pass over in silence the magnificent discoveries in 

 North America, which are principally due to the researches of Professors Marsh, 

 Leidy, and Cope. The diceratherium, a rhinoceros with two horns placed trans- 



