Page:The Geologist, volume 5.djvu/48

34 constant character in the antelopes, as differentiating various sub- genera or natural groups.

If any philosophical thinker can explain what is the vera causa which has provided for the Cainotherium and Guanaco deep preorbital interspaces, whilst in their congeners the Dorcatherium and Vicuña, no such interspace exists, a character originally pointed out by Dr. J. E. Gray, and which according to my experience is the sole specific difference which can be demonstrated, such explanation will be of great benefit to zoological science. The above observations are made solely with a view of suggesting further inquiry on this most interesting topic. I trust that some of those writers who have so carefully studied the osteology of Ruminantia, may be led to reconsider the question, and to make further observations on the function of the facial interspaces in both recent and fossil ruminants.

It has been suggested to me, that the two holes in the Microtherium skull, as they are undoubtedly asymmetrical, might have been produced artificially or accidentally, the bone at this place being exceedingly thin. Should such a theory be proved correct, the Microtherium of the Auvergne deposit would still find its nearest analogue in the existing Meminna of Ceylon, and by the demonstration of this affinity, still further corroborate the truth of Professor Owen's generalization,—"The affinity of the Microtheres to the Cheorotains is nevertheless very close" (Palæontology, 2nd ed. p. 372). 

In a tolerably deep ravine, surrounded by trees and brushwood growing in wild profusion, was, until lately, a cave, in that member of the carboniferous formation locally called the "Great Limestone," and situated about one mile and a quarter north from the town of Stanhope, in the county of Durham. The limestone is now being worked for the purpose of supplying the Weardale Iron Company with a flux used in the operation of smelting their ironstone; and consequently the cave has been laid bare to the light of day.

The cave was much visited a few years ago, both by strangers and persons living in the locality, but probably few of the visitors ever studied the excavating forces by means of which the cave was hollowed out of the solid limestone, and fewer still, if any, would think that they were treading on a primeval burial-place.

Doubtless the excavation must be mainly due to aqueous agency, but a reference to Sir Charles Lyell's 'Principles of Geology,' Professor Phillips's 'Treatise on Geology,' and Richardson's 'Geology,' shows that our leading writers on this subject consider that the first