1869.] Geolof/y and Fala2ontohgy. 543 



annually from our Coal-measures proper, are obtained from this 

 area. 



From coal we pass to tin, copper, lead, iron, zinc-ore, nickel, 

 wolfram, manganese, arsenic, &c., and then to building-stones, 

 ornamental marbles, roofing-slates, flagstones, lime, whetstones, 

 clays for pottery, &c., yielding a total value of 1,876,739Z. for the 

 two western counties. 



The Depths of the Sea. — In a lecture lately delivered before 

 the Koyal Dublin Society, by Prof. Wyville Thomson, the lecturer 

 gives us the results of dredging operations carried on by Dr. Car- 

 penter and himself last year in deep water between the Faroe 

 Islands and the Hebrides. 



Two areas were explored — a "cold area," where the bottom 

 was of stones and coarse sand, and on which the thermometer 

 registered a minimum temperature of 32° F., and where the fauna 

 consisted of a meagre sprinkling of boreal and arctic forms — and 

 a " warm area," the " Gulf-stream area " (530 fathoms deep), with 

 a minimum temperature of 47^"5 F., where the floor was covered 

 with fine grey slimy mud, technically called " ooze," but which 

 Prof. Wyville Thomson considers should be called " chalk-mud." 

 This area, which formerly yielded only the shells of a Khizopod 

 (Glohigerina), now proved to be also rich in siliceous sponges, 

 about forty of which were obtained on one occasion, a little south 

 of the Faroes. Most of these sponges had long and venerable 

 beards of flint-spicules, as fine as the finest floss- silk, spreading out 

 into the chalk-mud in all directions. These beards brought up, 

 entangled in them, small clams, starfishes, and minute crustaceans ; 

 and among the mud were scattered the shells of the beautiful and 

 well-known Pteropods of the Gulf-stream. 



There can be no doubt, adds Prof. WyviUe Thomson, that Chalk 

 is now being formed in the depths of the Atlantic ; and not only 

 Chalk, but The Chalk — the Chalk of the Cretaceous Period. That, 

 in fact, the physical and biological conditions of the greater part of 

 the ocean have remained unaffected by the later geological changes 

 embraced within the Tertiary and Quaternary Periods, which 

 represent only minor oscillations, the deposits formed during those 

 periods being all laid down in comparatively shallow water, as 

 shown by the nature and richness of their faunae. 



It is gratifying to find that whilst the results arrived at from 

 the more perfect appliances for modern deep-sea dredging have so 

 materially modified the late Professor Edward Forbes's conclusions 

 as to the depths in the ocean at which life could be sustained — yet 

 they have also tended to confirm the doctrine which he long ago 

 enunciated, that the persistence of the same ftiuna over an extended 

 geological area did not prove it to be synchronous, but rather the 

 reverse. 



