- 
  
  11- Nearly half of the valuable mineral deposits in the world occur in the rocks if this period.
23- Shelled brachiopods appear - 
  
  Geological Timescale
 - 
  
  7- some scientists believe that humans kind has caused mass extinctions of plant and animal species, polluted the oceans and altered the atmosphere.
38- environmental change cause mass extinction of sea invertibrates (trilobites & eurypterids) as the sea retreat - 
  
  14-There is argument as to when this epoch began, some scientists think it began with the industrial age in the early 1800's other with the atomic age in 1950's.
28- Small rodents evolve. - 
  
  31-Huge plants begin to develop , early amphibians form.
24- Eurypterids (sea scorpions), sea stars and coral became more common. - 
  
  1- There is very little plant life during the period.
37- Age of fishes, fish that can breath out of the water and spend time on land form. - 
  
  2- Swamps and forests cover the land.
10- The presence of stromatolites indicates that shallow seas covered much of the earth during intervals in this period. - 
  
  4- Giant cockroaches appear.
15- Coal deposits form. - 
  
  30- Colonies of tiny invertebrates call graptolites florished and vertibrates appear, fish did not have jaws or teeth and their bodies were covered with bony plates.
19-The last glacial period ended and sea levels rose, great lakes formed. - 
  
  16- Welcome to the world of the dinosaur! Enter the squirrel sized dinosaur & the first forest dwelling mammals appear.
8- Appalachian Mountains are created because of the collins of tectonic plates & savannahs form. - 
  
  3- Flying reptiles called pterosaurs are in the air now.
13- Whoa those dinos are getting big & dominate the land- lizard hipped and bird-hipped appear-carnivores and herbivores have arrived. - 
  
  33-Vascular land plants and animals, such as scorpion begin to evolve on land
37- Age of fishes, fish that can breath out of the water and spent time an land time. - 
  
  12- First primates evolve.
18- Various species migrated between continents across land bridges. - 
  
  17- Flying squirrels, whales and bats appear.
26- First modern horse appear. - 
  
  22- Trilobites appear.
19- The last glacial period ended and sea levels rose, Great Lakes formed. - 
  
  21- Early reptiles resembling large lizards appear.
25- World wide temperature drop about 4 degrees celsius (39.2 degrees fahrenheit) - 
  
  20- Species that did not evolve to survive extreme cold moved to warner climate areas of became extinct (dire wolf & giant ground sloth)
28- Morden human developed agriculture and used tools made of bronze and iron. - 
  
  32- Antarctic icecaps begin to form.
34- Ichthyosaurs are living in the ocean, new invertebrates call ammonite develop. - 
  
  6- Himalayas develop due to uplifting caused by the indian subcontinent and eurasian continents colliding.
9- Homosapien (modern humans) appeared & are hunters.