The Birmingham age-herald., 1915-07-25
Diagram Bridge That Connected America with The Black
 Portions Are Those Now Submerged.

genus originated How did these genera or their successors disperse? If they could not fly or were not transported, then he insists. they must have dispersed by means of existing land bridges and occasionally by natural marine grass rafts. The distance between Farce Islands and Scotland and between tho latter and western Norway is 240 miles in each case. The water depths existing between them today and in the other spaces was caused, geologists assert, by tie weight of successive Ice caps, depressing the earth crust. Some geo1ogists figure as many as six successive ice caps The number has little bearing on the matter since the last one was sufficiently appall- ing to make off perfect navigation at the present time, where walking had former ly been good. I say appalling because there is no doubt that the last ice cap, still rece1ing, northward, pounded the earth crust down to stay where 1t is while the first ice caps did no such stunt. One or several times 1t is assumed, the earth arose several hundred or more feet after the first ice cap receded. ,
 Archibald Geikie accumulated a lot of data on the subject which remains in his still authoritative work on "The Great Ice Age" So, the geologist's data Is used by paleontologists to support hypotheti. cal land bridges in order to account for migrations of men, other mammals, fightless birds, reptiles, crustaceans, in- vertebrates, trees, and plants which had seeds too heavy to be borne by winds and which sank in water rather than swim for it.
 Just how invertebrates migrate long distances is a matter which it is to be hoped Professor Ingen or others will clear up. I have seen clans travel by suction, but only on the bottom of water areas. Stejneger sets up such Ataantic and Arctalantic biota as world girdlers on the land bridges, but without describ- ing the process. Among these he men, tions terrestrial molluscs, earti,worms, 1sopod crustaceans, noctuid moths, bum- ble bees and an entire series of insects of the orders of lepidoptera, hemiptera and coleoptera.
 Some of these are essentially slow travellers and probably required hun dreds, perhaps thousands of years to dis perse the tremendous distances across those land bridges and over the moun- talns and plains of tho mainlands. Give a pair of snails several millions of years and they and their descendants could no
 
 kind, however slow cartoonist might de- pict them
 Among the mammals common to the whole sectional circle are the variable hare, the lemming, the red-backed field mouse, the wild reindeer the red deer, very primitive horses and the extinct mammoth
 When one considers the several types or men, other animals ;nd plants that nave apparently endured continuously since early Pleistocene times, and some or them much longer, in the cold storage sectlon CT the world. there "annot be the slightest doubt that if land bridges ex- lsted, there wes ample travelling done over them in both directions The prlnceton expedition will at least have the satisfaction hat ali of the evidence collected supports the hypothesis of Ma.aoraaor-Scotlanl land bridge Even . been.