176 A. P. COLEMAN DRY LAND IN GEOLOGY 



of Lake Bonneville, as read by a Gilbert, give more instruction in regard 

 to wave work than all the foam and tumult of the surf on the strand. 



The geologist is essentially a land animal, and yet until recently most 

 books on geology, especially text-books, have had surprisingly little to say 

 of the land and its conditions. The writers seemed all to belong to the 

 blue-water school, so much of their space has been given to the sea and 

 its inhabitants. It is true that continents were mentioned, almost apolo- 

 getically, when one came to the Cenozoic mammals, but even the Glacial 

 period did not lift geology above the sea for some of the older writers, 

 who preferred icebergs to glaciers for the manufacture of boulder-clay. 



This concentration on the sea and its life went to astonishing lengths 

 in the more ancient parts of geological history. Like most of our older 

 geologists, my first nourishment in the science was drawn from Dana's 

 "Manual." Unfortunately that earliest of text-books has been lost, but 

 curiosity led me to glance over his fourth edition (1895) to see how the 

 dry land fares in its pages. 



There is the usual fiery introduction to historical geology, dividing 

 Archean times alliteratively into Astral, Azoic, and Archeozoic eons, with 

 a lithic era beginning at 2,500° Fahrenheit and an oceanic era commenc- 

 ing when the earth had cooled to 500°, followed by eras of the earliest 

 plants and the earliest animals as the boiling ocean cooled to endurable 

 temperatures. When the streaming waters had permanently condensed 

 in the hollows of the original crust, there was left a V-shaped nucleus of 

 dry land about which the continent of North America Avas to be built up. 

 After this encouraging start with a quite respectable dry-land area as a 

 foundation, historical geology becomes submerged in seas, mostly shallow, 

 until the end of the Silurian. Out of 114 pages devoted to this part of 

 the world's history, the total number of lines referring to the land and its 

 inhabitants amount to only one page, while the Devonian land plants and 

 animals are given only 4 pages out of 46. It is true that most of the 

 Carboniferous chapter is devoted to the rank growths of the coal swamps, 

 but these amphibious plants have little to do with actual dry land. They 

 never rise far above sealevel and are frequently lowered beneath it to get a 

 fresh covering of mud or sand. The araucarias of the hills inland are 

 barely mentioned, and it is not till one gets well on into the Mesozoic that 

 the dinosaurs compel the student to depart a little from the seashore. 

 Even then there is a suggestion that at least some of the clumsy beasts 

 preferred splashing along the mud flats or paddling in the lagoons. 

 There is no hint of lean creatures hastening with long strides to the 

 shrinking water-holes of a semi-arid region. . 



Another stand-by of student days, this time in Germany, was Credner's 

 "Geologie/' which up to the end of the Devonian gives 2 pages out of 58 



