1868. | Geology and Palxontology. 575 
Natural History.* The frightful destruction caused by the eruptions 
of Mauna Loa has on several occasions drawn public attention to 
this group of volcanoes, so that Mr. Brigham’s admirable essay 
possesses a more than geological interest. Two conclusions of a 
purely scientific nature are, however, especially worthy of record. 
The author observed that although the craters of the group occur 
along a line supposed to be a line of fissure, as in other regions, 
yet that the major axes, or directions, of the craters were ‘parallel 
to one another at an angle of 26° from the trend of the group; in 
other words, the supposed volcanic fissure trends N. 64° W., the 
major axes being N. and §. On following out the idea suggested 
by this circumstance the author found that the major axes of craters 
are always at right angles to the mountain chains in which they 
are situated. ‘Thus he was led to reconsider the whole theory of 
volcanoes, and his conclusion is that the theory of an unequally 
contracting crust, causing certain portions to fall below the general 
level, opening rents at the boundaries, and forcing up molten 
matter to the surface, seems to satisfy the known condition of vol- 
canoes better than any other. 
Mr. R. D. Darbishire has published in the memoirs of the 
Literary and Philosophical Society of Manchester t a paper on 
some superficial deposits at Great Orme’s Head, in which he describes 
“ Pholas-burrows” as still discernible in the limestone rock at 
various heights up to 570 feet, and the legitimate conclusion which 
he draws is that the district has been under water since it was 
covered with ice. He hag also discovered similar “ Pholas-holes” 
near Buxton at a height of about 1,400 feet. If these holes are 
really the borings of Pholades, the fact is of the greatest interest ; 
and the photographs of the specimens, by which the paper is 
illustrated, certainly lend great probability to the author’s inference. 
In a paper read before the Royal Geological Society of Ireland 
last November, “On Parts of South Devon and Cornwall, with 
Remarks on the true Relations of the Old Red Sandstone to the 
Devonian Formation,” Mr. Jukes comes to the conclusion that the 
former “lies wholly below the Devonian slates and limestones, 
which contain marine fossils, both in Munster and Devon.” As to 
the Devonian formation and the Carboniferous Limestone, he does 
not wish to “dogmatize,” but it is evidently his belief that they are 
contemporaneous. We should mention that while Mr. Jukes’s geo- 
logical statements are always read with respect and attention, his 
onslaughts on Paleontology weaken the force of what would other- 
wise be regarded as a resonably good case, as it makes one suspect 
that the difference between his views and those of other geologists 
must there also be attributed to the want of power of observation. 
* Vol. i:,,part 3. + 3rd series, vol. iv. 
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