460 Sir H. H. Howorth — Geological History of the Baltic^ 



that they do in the more northern latitude regions, but very much 

 deeper. They occur in its abysmal depths, and we know quite 

 certainly that they occur there in very cold water. We also know 

 that the cold water in question is brought in by a deep current of cold 

 water from the Atlantic and has its complement in an outgoing upper 

 current which flows outwards. Not only so, we have an example 

 of the concurrent and contemporaneous effects of the presence of 

 a warm and an Arctic current side by side in Finmark and 

 the Lofoten Islands. In the former case the two zones of life 

 are separated by the North Cape, and in the latter by the islands just 

 named. In each case, within a few miles of each other, we have the 

 Yoldia fauna and the Tapes fauna living quite happily at the very 

 same time, the one supplied by an Arctic current and the other by the 

 Gulf Stream. Not only so, but off the north-west of the Lofoten 

 Islands, the Yoldia occurs living, not as Brogger demands, at a depth 

 of 10 to 30 fathoms, but of 60 to 100 fathoms, as we should expect 

 with the change in the latitude. We naturally conclude that if 

 these conditions, but on a greater scale, were repeated in the latitude 

 of the Christiania Fjord by a sufficient depression of the sea bottom, 

 the Arctic water would necessarily find its way thither and the 

 Yoldia and their friends would thrive there, while at a higher level 

 quite close by, there would be living precisely the same fauna as 

 lives there at this moment. This is what is actually occurring on 

 some of the Norwegian fjords, where the great depth of water at 

 their lower end has induced a contrasted fauna between their upper 

 and lower reaches. 



Now it is quite certain that the molluscs in the raised Tapes beds 

 of the Trondhjem and Christiania Fjords were living several hundred 

 feet below the present raised beach levels, or rather at a greater 

 depth still, for we must add probably 90 feet to the level of the 

 latter in order to secure them a sufficient submergence. Inasmuch 

 as the difference in the present level between the rbWiV? beaches and 

 the Tapes beaches in the Christiania Fjord is very considerable, at 

 least 400 feet, it follows that the former must have been submerged 

 to a much greater depth than the latter, and in fact to a depth 

 approximating to 800 or 1,000 feet. In that case the necessary 

 conditions for the life of Yoldia must have existed there in 

 the same way that they exist in the North Lofoten waters now, 

 only at a greater depth. This seems to me to be an exceedingly 

 simple explanation, and it is conclusive for those who do not believe 

 in transcendental causes. It further dispenses with all the see-saw 

 and rocking-horse machinery of earth movements against which Suess 

 protests so strongly, which are incompatible with these movements, 

 having been caused by lateral thrusts, as now generally held, and 

 which the glacial theory requires to explain the facts. This is not 

 all, we can produce direct evidence of a very interesting kind that 

 the explanation here maintained is the true one. 



It is at all events a very remarkable fact that while the Yoldia 

 has become extinct in the Norwegian seas except in the north-west 

 corner of the Lofoten archipelago and perhaps the extreme north of 

 Finmark, the whole sea bottom along the coast of Norway is 



