HAMILTON >SCIENTIFIC ASSOCIATION. 21 



cod. Reptilian life is on the decline, and only one type of dein- 

 osaurs is found in cretaceous rocks — iguanodon. Of this in recent 

 years a number of ahnost entire skeletons have been found. It was 

 a herbaceous and probably an amphibian creature, able, no doubt, 

 to walk along the shores with an unwieldy gait on its long hind 

 legs, balancing itself by its strong niassive tail. Several kinds of 

 crocodile also found in cretaceous rocks. From rocks in Western 

 America have been found a long, snake-like animal, 40 feet, with 

 swan-like neck, which it could raise 20 feet out of the water or 

 dart to the bottom to catch its pre3^ Sea serpents were also 

 especially numerous. 



Remains of true birds have been found in cretaceous rocks. 

 Chalk is presumably pure limestone, composed chieflj^ of crumbled 

 foraminifera, urchins, molluscs, and other marine organisms. It 

 must have been laid down in a sea singularly free from sediment, 

 but not necessarily in deep seas. Cretaceous rocks cover large 

 areas in America, commencing at the Eastern States with no great 

 thickness, but deepening to westward until in Texas, Colorado, 

 Utah, and Wyoming they attain gigantic proportions, with a maxi- 

 mum thickness of 11,000 to 13,000 feet. In their upper parts, 

 called the Laramie group, they contain many land plants, half of 

 which are allied to still living American trees, and in some places 

 these plants are aggregated into valuable seams of coal. In Can- 

 ada the interior continental plain contains these rocks largel5^ In 

 them 179 species of plants and 394 species of animals have been, 

 found. The coal-beds of Anthracite and Crow's Nest Pass are of 

 this age. It is believed that about the beginning of the cretaceous 

 period the Rocky Mountains began to be uplifted, whilst the plains 

 sank beneath the sea. Then were deposited on the gradually sink- 

 ing floor the sandstones and shales of this series in which occur the 

 remains of deinosaurs, fresh-water shells, land plants, with occa- 

 sional beds of coal. In the interior continental plain the sand- 

 stones and shale of the Laramie series are 5,000 or 6,000- feet thick. 



Cainozoic : During this period the continents began to take 

 their present shape. That great series of mountains extending 

 from the P3'renees across Europe and Asia to Japan were thrown 



