?^T 



THE 



GEOLOGICAL MAGAZINE. 



No. LXXIX.— JANUARY, 1871. 



I. — The Geological Beabings of Eecent Dkep-Sea Soundings. 

 By A. H. Green, M.A., E.G.S., etc. 



OF the immense value of the recent deep-sea soundings there can 

 be no doubt, but whether geologists will side with Dr. Car- 

 penter in the deductions he has attempted to draw from these 

 explorations seems to me a matter of considerable doubt : and 

 I propose to discuss here several difficulties that have occurred to 

 myself on this head. I shall take as my text Dr. Carpenter's last 

 exposition of his views in a letter to Nature of Oct. 27th, 



1st. With regard to the statement that we may be said to be still 

 living in the Cretaceous epoch.^ 



I take it that by a geological epoch we mean a period of time 

 during which there lived and flourished a group of animals, which, 

 when looked at in a large way, has a character of its own, which 

 marks it off in an unmistakeable manner from a group which went 

 before and from another group which followed it. This character- 

 istic stamp, which distinguishes the fauna of any epoch from that of 

 all other epochs, is spoken of as its fades ; and when, in ascending or 

 descending through a series of stratified rocks, we find at any point a 

 marked change in the fades of the contained fossils, we say that at 

 that point we have passed from one geological epoch to another. 

 Whether the hard and fast lines which we are thus enabled to draw 

 between successive geological epochs are due or not to great un- 

 represented gaps in the record of the earth's history furnished by 

 the stratified rocks, does not now concern us : it is enough that such 

 lines exist, and that by means of them we can parcel out bygone 

 time into geological epochs. 



Can, then, the fauna of the sea on whose bed the Chalk of to-day 

 is forming be said, on a hroad view, to be the same as the fauna whose 



1 This theory was, we believe, put forward, in the first instance, on the authority of 

 Prof.Wyville Thomson, F.E.S., Dr. Carpenter's colleague in the Goyernment Dredging 

 Expeditions. — Edit. Geol. Mag. 



VOL. VIII.— NO. LXXIX. 1 



